C# - .NET MASTERS BLOG ®

WPF

2012-01-05T08:40:00.001-08:00

Rendering Tier 0 directx 7 aşağısı

Rendering Tier 1 Directx 7-9

Rendering Tier 2 Direct x 9+

int renderingTier = (RenderCapability.Tier >> 16);

if (renderingTier == 0)
{ ... }
else if (renderingTier == 1)
{ ... }

milcore.dll media integration layer MIL

DWM Desktop Wİndow Manager

wpf ile herşey 3d render edilir 2 boyutlu şeyler bile üçgenlere çevrilip 3d pipeline dan geçer

The client profile is the subset of the .NET Framework that’s required for rich client applications
like WPF. It doesn’t include server-side features such as ASP.NET, debuggers, developer tools, code compilers.

Concurrent Bag

2012-01-05T06:07:00.001-08:00

    [Serializable]
    public class ConcurrentList<T> : ConcurrentBag<T> //where T : ICloneable
    {
        private object lockObject = new object();

        public ConcurrentList<T> CloneOnlyList()
        {
            lock (lockObject)
            {
                ConcurrentList<T> clone = new ConcurrentList<T>();
                foreach (T t in this)
                {
                    clone.Add(t);
                }
                return clone;
            }
        }

        public T this[int i]
        {
            get
            {
                return this.ElementAt(i);
            }
        }

        public void Clear()
        {
            T someItem;
            lock (lockObject)
            {
                while (!this.IsEmpty)
                {
                    this.TryTake(out someItem);
                }
            }
        }
    }

lock static objects

2012-01-05T01:26:00.001-08:00

// C#
lock(typeof(Foo)) { // BAD CODE! NO! NO! NO!
// statements;
}
' VB .NET
SyncLock GetType(MyClass) ' BAD CODE! NO! NO! NO!
' statements
End SyncLock
Ã‚Â…into the following good code:
// C#
lock(somePrivateStaticObject) { // Good code!
// statements;
}
' VB .NET
SyncLock GetType(somePrivateStaticObject) ' Good code!
' statements
End SyncLock

Cathing exceptions in pararlel for

2011-12-27T01:34:00.001-08:00

    private static void ProcessDataInParallel(byte[] data)
    {
        // Use ConcurrentQueue to enable safe enqueueing from multiple threads.
        var exceptions = new ConcurrentQueue<Exception>();

        // Execute the complete loop and capture all exceptions.
        Parallel.ForEach(data, d =>
        {
            try
            {
                // Cause a few exceptions, but not too many.
                if (d < 0x3)
                    throw new ArgumentException(String.Format("value is {0:x}. Elements must be greater than 0x3.", d));
                else
                    Console.Write(d + " ");
            }
            // Store the exception and continue with the loop.                    
            catch (Exception e) { exceptions.Enqueue(e); }
        });

        // Throw the exceptions here after the loop completes.
        if (exceptions.Count > 0) throw new AggregateException(exceptions);
    }

Parallel for

2011-12-27T00:56:00.001-08:00

    int[] nums = Enumerable.Range(0, 1000000).ToArray();
        int[] results = new int[nums.Length];
        Parallel.For(0, nums.Length, (i,loopsatate) =>
            {
                if (i < 100)

                    results[i] = 2 * nums[i];

                else
                {
                    loopsatate.Stop();
                    return;
                }
            }
            );

Struct larda aynı yere iki değişkenle bakmak

2011-12-27T00:19:00.001-08:00

[StructLayout(LayoutKind.Explicit)]
struct TestExplicit
{
    [FieldOffset(0)]
    public long lg;
    [FieldOffset(0)]
    public int i1;
    [FieldOffset(4)]
    public int i2;
}
  public  static void Main(string[] args)
    {
        TestExplicit t = new TestExplicit(); t.lg = long.MaxValue;
        int a = t.i1;
        int b = t.i2;
    }

Oracle Notes

2011-02-17T05:34:00.001-08:00

DML data manipulation language

Client -server uygulamalar direk client daki program database e erişir

Multitier application lar çok katmanlı yazılımlar presentation katmanı application katmanı database katmanı birbirlerinden farklı

raid 0 stripping sadece performans

raid 1 mirroring sadece veri güvenliği

raid 1+0 stripping +mirroring performans + güvenlik

raid 5 stripping with parity performans +güvenlik ama disk boyutunu ikiye katlamadan

Oracle Net protocol 1521 1526

MVC ile three tier application farkı mvc de her tier birbirine mesaj gönderir ama three tier da üst ile alt birbirini görmez

Oracle file extension

2011-02-17T04:52:00.001-08:00

-Oracle ın disk block boyutları sisteminki ile aynı veya kolay bölünebilir olmalı asla sistem bloklarının boyutundan küçük olmamalı

-Oracle data dosyalarının uzantısı .dbf data base file

-Archive log files has extension .log .arc .arch

Oracle Buffer cache state

2011-02-17T04:36:00.001-08:00

Free blocks

Pinned bloklar şu anda erişilen bloklar

Dirty bloklar değiştirilmiş olanlar

Dirty bloklar database kapatma komutu ile her 3 saniyede bir checkpoint oluşturulduğunda diske yazılır

Parsing Oracle Queries

2011-02-17T01:45:00.001-08:00

Oracle a bir query gittiği zaman sırayla

-Query nin imlasının (syntax) doğru olup olmadığı kontrol edilir

-Kullandığımız objeler kontrol edilir

-Yetkileriniz kontrol edilir

-Query database diline çevrilir(byte code p-code

-Oracle en optimum işletme planını yolunu çıkarır

BI

2011-02-17T01:23:00.001-08:00

DSS decision support system.

OLAP Online Analytical Procesing

OLTP Online Transactional Processing

System Global Area Bir oracle instanceının ramde kullandığı ortak alan

Shared Pool bu alandaki objeler sık kullanıldıkları için diske yazılmazlar

-Library Cache

-Dictionary Cache

-Quickest result Cache

-Sql result Cache

bunlar daha önceden hesaplanmış değerleri içerir birdaha birdaha hesaplanmaz.

Grid computing vs cluster computing

2011-02-17T00:46:00.001-08:00

Grid computing farklı domainlerdeki bilgisayarların ki çoğunlukla homojen bir dağılım söz konusu değildir ortak bir hedef için birleşik çalışmaları cluster computing ise tek süper güçlü bir bilgisayar yerine birçok bilgisayarın tek bir bilgisayar gibi çalışması.Oracle

Oracle 11 g- G deki G nedir

2011-02-17T00:37:00.001-08:00

Oracle 1990 larda internetin popülerleşmesi ile oracle 8i yi çıkardı I nin buradaki anlamı internetti.Şu sıralar popüler olan grid computing in g side oracle 11g ye ismini vermiştir

Chain of responsibility

2010-12-18T13:31:00.001-08:00

http://nchain.sourceforge.net/

class CheckAuthority {
 
    public static void main(String[] args) {
        ManagerPPower manager = new ManagerPPower();
        DirectorPPower director = new DirectorPPower();
        VicePresidentPPower vp = new VicePresidentPPower();
        PresidentPPower president = new PresidentPPower();
        manager.setSuccessor(director);
        director.setSuccessor(vp);
        vp.setSuccessor(president);
 
        //enter ctrl+c to kill.
        try{
            while (true) {
                System.out.println("Enter the amount to check who should approve your expenditure.");
                System.out.print(">");
                double d = Double.parseDouble(new BufferedReader(new InputStreamReader(System.in)).readLine());
                manager.processRequest(new PurchaseRequest(0, d, "General"));
           }
        }
        catch(Exception e){
            System.exit(1);
        }  
    }
 
}

Generator

2010-12-18T13:18:00.001-08:00

In short, a generator <I>looks like</I> a function but <I>behaves like</I> an iterator.

public static IEnumerable<int> GetEven(IEnumerable<int> numbers)
{
    foreach (int i in numbers)
    {
        if ((i % 2) == 0)
        {
            yield return i;
        }
    }
}

Lazy evaluation

2010-12-18T13:12:00.001-08:00

The benefits of lazy evaluation include: performance increases due to avoiding unnecessary calculations, avoiding error conditions in the evaluation of compound expressions, the capability of constructing potentially infinite data structures, and the capability of defining control structures as abstractions instead of as primitives.

In computer windowing systems, the painting of information to the screen is driven by "expose events" which drive the display code at the last possible moment. By doing this, they avoid the computation of unnecessary display content

The opposite of lazy actions is eager evaluation, sometimes known as <I>strict evaluation</I>. Eager evaluation is the evaluation behavior used in most programming languages.

Lazy evaluation refers to how expressions are evaluated when they are passed as arguments to functions and entails the following three points:

Private class data pattern

2010-12-18T13:06:00.001-08:00

 public class Circle
 {
   private double radius;
   private Color color;
   private Point origin;
   public Circle(double radius, Color color, Point origin)
   {
     this.radius = radius;
     this.color = color;
     this.origin = origin;
   }
   public double Circumference
   {
     get { return 2 * Math.PI * this.radius; }
   }
   public double Diameter
   {
     get { return 2 * this.radius; }
   }
   public void Draw(Graphics graphics)
   {
     //...
   }
 }

???

2010-06-03T02:04:00.001-07:00

        1: int result= 2;   

       2: result = result<<2 +1;    

       3: std::cout << "Result is " << result << '\n';

       4: return (0);

Real Programmers

2010-06-03T02:03:00.001-07:00

Real Programmers Don't Write Specs

Real Programmers don't write specs -- users should consider themselves lucky to get any programs at all and take what they get.
Real Programmers don't comment their code. If it was hard to write, it should be hard to understand and even harder to modify.
Real Programmers don't write application programs; they program right down on the bare metal. Application programming is for feebs who can't do systems programming.
Real Programmers don't eat quiche. In fact, real programmers don't know how to SPELL quiche. They eat Twinkies, and Szechwan food.
Real Programmers don't write in COBOL. COBOL is for wimpy applications programmers.
Real Programmers' programs never work right the first time. But if you throw them on the machine they can be patched into working in "only a few" 30-hour debugging sessions.
Real Programmers don't write in FORTRAN. FORTRAN is for pipe stress freaks and crystallography weenies.
Real Programmers never work 9 to 5. If any real programmers are around at 9 AM, it's because they were up all night.
Real Programmers don't write in BASIC. Actually, no programmers write in BASIC, after the age of 12.
Real Programmers don't write in PL/I. PL/I is for programmers who can't decide whether to write in COBOL or FORTRAN.
Real Programmers don't play tennis, or any other sport that requires you to change clothes. Mountain climbing is OK, and real programmers wear their climbing boots to work in case a mountain should suddenly spring up in the middle of the machine room.
Real Programmers don't document. Documentation is for simps who can't read the listings or the object deck.
Real Programmers don't write in PASCAL, or BLISS, or ADA, or any of those pinko computer science languages. Strong typing is for people with weak memories.
Real Programmers only write specs for languages that might run on future hardware. Noboby trusts them to write specs for anything homo sapiens will ever be able to fit on a single planet.
Real Programmers spend 70\% of their work day fiddling around and then get more done in the other 30\% than a user could get done in a week.
Real Programmers are surprised when the odometers in their cars don't turn from 99999 to 9999A.
Real Programmers are concerned with the aesthetics of their craft; they will writhe in pain at shabby workmanship in a piece of code.
Real Programmers will defend to the death the virtues of a certain piece of peripheral equipment, especially their lifeline, the terminal.
Real Programmers never use hard copy terminals, they never use terminals that run at less than 9600 baud, they never use a terminal at less than its maximum practical speed.
Real Programmers think they know the answers to your problems, and will happily tell them to you rather than answer your questions.
Real Programmers never program in COBOL, money is no object.
Real Programmers never right justify text that will be read on a fixed-character-width medium.
Real Programmers wear hiking boots only when it's much too cold to wear sandals. When it's only too cold, they wear socks with their sandals.
Real Programmers don't think that they should get paid at all for their work, but they know that they're worth every penny that they do make.
Real Programmers log in first thing in the morning, last thing before they go to sleep, and stay logged in for lots of time in between.
Real programmers don't draw flowcharts. Flowcharts are after all, the illerate's form of documentation.
Real Programmers don't use Macs. Computers which draw cute little pictures are for wimps.
Real Programmers don't read manuals. Reliance on a reference is the hallmark of a novice and a coward.
Real Programmers don't write in COBOL. COBOL is for gum chewing twits who maintain ancient payroll programs.
Real Programmers don't write in FORTRAN. FORTRAN is for wimpy engineers who wear white socks. The get excited over finite state analysis and nuclear reactor simulations.
Real Programmers don't write in Modula-2. Modula-2 is for insecure analretentives who can't choose between Pascal and COBOL.
Real Programmers don't write in APL, unless the whole program can be written on one line.
Real Programmers don't write in Lisp. Only effeminate programmers use more parentheses than actual code.
Real Programmers distain structured programming. Structured programming is for compulsive neurotics who were prematurely toilet trained. They wear neckties and carefully line up sharp pencils on an otherwise clear desk.
Real Programmers scorn floating point arithmetic. The decimal point was invented for pansy bedwetters who are unable to think big.
Real Programmers know every nuance of every instruction and use them all in every Real Program. Some candyass architectures won't allow EXECUTE instructions to address another EXECUTE instruction as the target instruction. Real Programmers despise petty restrictions.
Real Programmers don't like the team programming concept. Unless, of course, they are the Chief Programmer.
Real Programmers have no use for managers. Managers are sometimes a necessary evil. Managers are good for dealing with personnel bozos, bean counters, senior planners and other mental defectives.
Real programmers ignore schedules.
Real Programmers don't bring brown bag lunches to work. If the vending machine sells it, they eat it. If the vending machine doesn't sell it, they don't eat it.
Real Programmers think better when playing Adventure or Rogue.
Real Programmers use C since it's the easiest language to spell.
Real Programmers don't use symbolic debuggers, who needs symbols.
Real Programmers only curse at inanimate objects.

Float integer

2010-06-03T01:45:00.001-07:00

        1: int main()

       2: {

       3:      float result;      

       4:  

       5:     result = 1/3;      

       6:  

       7:      std::cout << "Result is " << result << '\n';

       8:      std::cin>> result;

       9:      return (0);

      10: }

Sonuç ??

Static C++

2010-06-03T01:15:00.001-07:00

        1: #include <stdio.h>

       2: #include <iostream>

       3:  

       4: int first(void)

       5:   {

       6:       int i = 0; 

       7:  

       8:      return (i++);

       9:  }

int second(void)

{

    static int i = 0;

    return(i++);

}

  

  

int main()

{

int counter;

for(counter = 0;counter <3 ;counter++)

{

    printf("First %d \n", first());

  

}

for(counter = 0;counter <3 ;counter++)

{

    printf("Second %d \n", second());

  

}

std::cin>>counter;

    return (0);

  

}

sonuçlar

first 0 0 0

second 0 1 2

şeklinde.C# da bir fonksiyon içine static değişken tanımlanamazken c++ da tanımlabiliyor ve değer atansa bile sadece ilk oluşturur ken kullanıyor

Hata Nerede

2010-06-03T01:02:00.001-07:00

        1: #include <iostream>

       2:  

       3: void main()

       4: {

       5:     std::cout<<"Hello World \n";

       6:     return (0);

       7: }

Reflector on the job

2009-05-27T06:06:00.001-07:00

You have a list full of custom class items and want to find according to one property.Ok the best way is lambda functions(Or Not?).Other than lambda functions you can use reflection and use some code like:

     public NeuronList FindByProperty(string PropertyName, object Value)

     {

         try

         {

             NeuronList foundItems = new NeuronList();

             foreach (NeuronBase item in List)

             {

                 System.Type itemType = item.GetType();

                 PropertyInfo[] itemProperties = itemType.GetProperties();

                 foreach (PropertyInfo info in itemProperties)

                 {

                     if (info.Name == PropertyName)

                     {

                         object itemValue = info.GetValue(item, null);

                         if (Convert.ChangeType(itemValue, info.PropertyType).Equals(Value))

                         {

                             foundItems.Add(item);

                         }

                     }

                 }

             }

             return foundItems;

         }

         catch (Exception ex)

         {

             throw new Exception("Can not find property", ex);

         }

     }

Neural Networks

2009-05-27T06:01:00.001-07:00

Have written a basic ann app which can do anything known about neural networks and has a simple ui, of course it needs lots of improvements but to get the basic idea you can take a look.

I am assuming you have some idea about neural networks

BaseNeuron is my neuron class which derives from user control. Input Neuron Middle Neuron and Output Neurons are derived from Base Neuron .Input Neuron is the neurons where you apply input output neurons are as name implies output :).Every neuron can be connected to another by synaps.A synaps becomes more powerful as it transmit signals

NeuralNetwork is our network and contains two collections inputneurons and neurons(middle and output).NeuralNetwork stores the fired neurons you can find all fired neurons in our network in nth turn.

NeuralPort is the ports where you can make connections(input and output) to ann.

NeuronList is our List that hold neurons and enables us to find desired neuron by neuronNo

NetworkVisualiser is the gui that shows our neural network connections and fired neurons.

Network builder is obsolete now network build her own.

I am uploading a copy in google code under hyacinth.

http://code.google.com/p/hyacinth/downloads/list

N-Depend

2009-05-20T06:12:00.001-07:00

I have been busy with artificial neural networks for some time so couldn’t post much.

NDepend is a static code analyzer it inspects your code and tells dependincies metrics code analysis. I found metrics very useful.It tell if you used boxing if your namings are wrong, if you used wrong access modifier, you have too many fields.You can also write your own queries it uses cql code query language very similar to sql, You can select methods which returns int.

http://www.ndepend.com/ is the web page.

Take a look

Hyacinth v1.1

2009-05-07T11:14:00.001-07:00

I added some missing things to hyacinth my jabber client.She can now encrypt messages .

Pollard’s Rho factoring algorithm in C#

2009-04-27T04:01:00.001-07:00

Pollard’s rho algorithm is used to factor composite integers. Suppose you have 8633, 89 *97 are the factors.

Here is the code:

     static void Main(string[] args)

            {

                Int64 a = p.PollardRho(12187823);

            }

            public Int64 customFunct(Int64 param, Int64 mod)//Custom number generator

            {

                return ((param * param + 1 )% mod);

            }

            public Int64 PollardRho(Int64 number)

            {

                Int64 a = 2, b = 2, tmp;//initail starting values

                while(true)

                {

                a = customFunct(a,number);//get first number

                b = customFunct(customFunct(b,number),number);//get second double run custom func

                tmp = GCD(Math.Abs(b-a), number);// if a =  b mod d(divisor one of the divisors of our number) then a-b is multiple of d and number is multiple of d 

                if (tmp > 1)

                    break;

                }

                return tmp;

            }

            public Int64 GCD(Int64 x, Int64 y)//Greatest Common Divisor

            {

                if (x == 0)//Find it? return

                    return y;

                if (y == 0)//Find it? return

                    return x;

                x = x % y;// take the mod of the large val to small one if the order is wrong in the next recursive loop it will be correct

                return GCD(y, x);//Parameters changed place

            }

I put comments on the code and included usage.The code includes a custom function you may experiment with and a greatest common divisor calculator.

Reflection

2009-04-26T05:55:00.000-07:00

This code is used to change all off one kind of controls one property to any value in a form.Hard to understand ? Ok let me give you an ex: you want to disable all text box in a form property is enabled value is false very easy.

     private static ArrayList controls = new ArrayList();

        public static Control[] LookControls(Form f,Type ctrlType,string property,object value)

        {

            foreach (Control c in f.Controls)

            {

                LookControls(c, ctrlType,property,value);

            }

            return (Control[])controls.ToArray(typeof(Control));

        }

        private static void LookControls(Control ctrl, Type ctrlType,string property,object value)

        {

            if (ctrl.GetType() == ctrlType)

            {

                controls.Add(ctrl);

                PropertyInfo p = ctrl.GetType().GetProperty(property);

                p.SetValue(ctrl, value, null);

            }

            if (ctrl.Controls != null)

            {

                foreach (Control ctrl1 in ctrl.Controls)

                {

                    LookControls(ctrl1,ctrlType,property,value);

                }

            }

        }

LU Decomposition and Linear Equation Solving in c#

2009-04-24T15:41:00.001-07:00

LU decomposition is used to write a matrix in Upper and Lower triangle forms which is used to solve linear equations.Here is my code for LU decomposition and Linear Equation Solving, it is based on some very old fortran code, i think lapack may have the original sources but they are hard to understand.I added a few comments but to really understand what is going on i can recommend using pen and paper and doing with hand.

     static void Main(string[] args)

    {

        double[,] lu = new double[3, 3] { { 2, 1, -1 }, { -3, -1, 2 }, { -2, 1, 2 } };

        double[] b = new double[] { 8, -11, -3 };

        double[] x = new double[3];

        int[] indx = new int[b.Length];

        Program p = new Program();

        p.LUDecompose(ref lu, ref indx);

        p.Solve(ref b, ref x, indx, lu);

    }

    private void LUDecompose(ref double[,] lu, ref int[] indx)

    {

        int i, imax = 0, j, k, n = lu.GetLength(0);

        double big, temp;

        double[] vv = new double[n];

        //preChecks

        if (lu.GetLength(0) != lu.GetLength(1) || lu.GetLength(0) != indx.Length)

            throw new Exception("matrix dimension problem only use square matrices");

        //for each row find the absolute value of the greatest cell and store in vv

        for (i = 0; i < n; i++)

        {

            big = 0.0;

            for (j = 0; j < n; j++)

                if ((temp = Math.Abs(lu[i, j])) > big) big = temp;

            if (big == 0.0)

            throw new Exception("singular matrix");

            vv[i] = 1.0 / big;//calculate scaling and save

        }

        //k is for colums start with the left look for the columns under the diagonal for the biggest value want to move the largest over diagonal

        for (k = 0; k < n; k++)//find the largest pivot element 

        {

            big = 0.0;

            for (i = k; i < n; i++)

            {

                temp = vv[i] * Math.Abs(lu[i, k]);

                if (temp > big)

                {

                    big = temp;

                    imax = i;

                }

            }

            if (k != imax)//do we need a row change 

            {

                for (j = 0; j < n; j++)// counter for the colums

                {

                    temp = lu[imax, j];// change the rows

                    lu[imax, j] = lu[k, j];

                    lu[k, j] = temp;

                }

                vv[imax] = vv[k];

            }

            indx[k] = imax;

            for (i = k + 1; i < n; i++)

            {

                temp = lu[i, k] /= lu[k, k];//divide pilot element

                for (j = k + 1; j < n; j++)

                    lu[i, j] -= temp * lu[k, j];

            }

        }

    }

    private void Solve(ref double[] b, ref double[] x, int[] indx, double[,] lu)

    {

        if (b.Length != lu.GetLength(0) || x.Length != lu.GetLength(0))

            throw new Exception("vector dimension problem");

        int n = lu.GetLength(0);

        int i, ii = 0, ip, j;

        double sum = 0;

        for (i = 0; i < n; i++) x[i] = b[i];

        for (i = 0; i < n; i++)

        {

            ip = indx[i];

            sum = x[ip];

            x[ip] = x[i];

            if (ii != 0)

                for (j = ii - 1; j < i; j++) sum -= lu[i, j] * x[j];

            else if (sum != 0.0)

                ii = i + 1;

            x[i] = sum;

        }

        for (i = n - 1; i >= 0; i--)

        {

            sum = x[i];

            for (j = i + 1; j < n; j++) sum -= lu[i, j] * x[j];

            x[i] = sum / lu[i, i];

        }

    }

The code also has an example how to use b is the vector right hand side of the equation x is the solution vector, lu is the matrix.

tricky or idiomatic

2009-04-23T23:50:00.001-07:00

Ok have written all this page and windows live writer stopped working when i was posting, i hate programs when they do that (dont get backup) i will tell about backing up in another post.I will not write all the stuff back i have things to do, please tell your best wishes to live writer group .

     int x = 2;

    int y = x << 1 | 1;

    int z = x << 1 + 1;

ok these are not same y = 5 and z is 8 because of order of evaluation.

    //x   y

    //0   2   

    //1   0

    //2   1

    int x, y = 1; ;

    x = (2 - y) * (1 + 3 * y) / 2;

    x = y + 1;

    if (x == 3) x = 0;

    switch (y)

    {

        case 2:

            x = 0;

            break;

        case 0:

            x = 1;

            break;

        case 1:

            x = 2;

            break;

        default:

            {

               throw new Exception("incorrect parameter");

            }

    }

ok here is 3 different codes that do the same thing : return values associated in table above code like 0 if 2 is given as parameter.

the first one is tricky and bad the second is good idiomatic and the last one is suboptimal and slow only may be used if algorith should be broken with future numbers.

Ok i know i didn’t told anything but i am sure codes will be explanatory enough.

Mixin ins in c# or code extensions

2009-04-22T12:31:00.001-07:00

Technorati Tags: mixin,mixin in,code extension,extension,c#,interface

      
        public interface IExtension

        {

        }

        public static class Extensions

        {

            public static string GetTypeInfo(this IExtension ext)

            {

                return String.Format("{0} {1}", ext.GetType().FullName, ext.GetHashCode().ToString());

            }

        }

        public static class Test

        {

            public static string GetTest(this IExtension debug)

            {

                return "Test string";

            }

        }

        class Program

        {

            static void Main()

            {

                var myObj = new MyClass();

                Console.WriteLine(myObj.GetTypeInfo());

                Console.WriteLine(myObj.GetTest());

                Console.Read();

            }

        }

        class MyClass : IExtension

        {

        }

C# does not support mixins ; mixins are like prewritten codes functions to be implemented by subclasses, it is different from interfaces interfaces are only signature does not contain functions mixins does. We can use code extensions to add extra functions to a class.It is pretty easy to use code extensions like above.

Lock

2009-04-22T04:29:00.001-07:00

Lock actually is the short for Monitor.Enter and Monitor.Exit

Here is the code

     class Program

        {

            static void Main(string[] args)

            {

                for (int i = 0; i < 100; i++)

                {

                    new Thread(Go).Start();

                }

                Thread.Sleep(1000);

                Console.Read();

            }

            static int val1 = 90, val2 = 10;

            static object locker = new object();

            static void Go()

            {

                lock (locker)

                {

                    if (val2 != 0)

                    {

                        Thread.Sleep(20);

                        Console.WriteLine(val1 / val2);

                        val2 = 0;

                    }

                    else

                    {

                        Console.WriteLine("attempted to divide by zero");

                    }

                }

                }

        }

lets look what happens when you start 100 threads of Go function starts and if you don’t lock gives a attempted to divide by zero exception.When you lock problem is solved, lets look at the il code:

    .method private hidebysig static void  Go() cil managed

    {

      // Code size       88 (0x58)

      .maxstack  2

      .locals init ([0] object CS$2$0000,

               [1] bool CS$4$0001)

      IL_0000:  nop

      IL_0001:  ldsfld     object ConsoleApplication12.Program::locker

      IL_0006:  dup

      IL_0007:  stloc.0

      IL_0008:  call       void [mscorlib]System.Threading.Monitor::Enter(object)

      IL_000d:  nop

      .try

      {

        IL_000e:  nop

        IL_000f:  ldsfld     int32 ConsoleApplication12.Program::val2

        IL_0014:  ldc.i4.0

        IL_0015:  ceq

        IL_0017:  stloc.1

        IL_0018:  ldloc.1

        IL_0019:  brtrue.s   IL_003e

        IL_001b:  nop

        IL_001c:  ldc.i4.s   20

        IL_001e:  call       void [mscorlib]System.Threading.Thread::Sleep(int32)

        IL_0023:  nop

        IL_0024:  ldsfld     int32 ConsoleApplication12.Program::val1

        IL_0029:  ldsfld     int32 ConsoleApplication12.Program::val2

        IL_002e:  div

        IL_002f:  call       void [mscorlib]System.Console::WriteLine(int32)

        IL_0034:  nop

        IL_0035:  ldc.i4.0

        IL_0036:  stsfld     int32 ConsoleApplication12.Program::val2

        IL_003b:  nop

        IL_003c:  br.s       IL_004b

        IL_003e:  nop

        IL_003f:  ldstr      "attempted to divide by zero"

        IL_0044:  call       void [mscorlib]System.Console::WriteLine(string)

        IL_0049:  nop

        IL_004a:  nop

        IL_004b:  nop

        IL_004c:  leave.s    IL_0056

      }  // end .try

      finally

      {

        IL_004e:  ldloc.0

        IL_004f:  call       void [mscorlib]System.Threading.Monitor::Exit(object)

        IL_0054:  nop

        IL_0055:  endfinally

      }  // end handler

      IL_0056:  nop

      IL_0057:  ret

    } // end of method Program::Go

As you can see it is a try finally block and monitor.enter and monitor.exit methods.If you replace lock with monitor codes given below il code will be same

     
        class Program

        {

            static void Main(string[] args)

            {

                for (int i = 0; i < 100; i++)

                {

                    new Thread(Go).Start();

                }

                Thread.Sleep(1000);

                Console.Read();

            }

            static int val1 = 90, val2 = 10;

            static object locker = new object();

            static void Go()

            {

                Monitor.Enter(locker);

                try

                {

                    if (val2 != 0)

                    {

                        Thread.Sleep(20);

                        Console.WriteLine(val1 / val2);

                        val2 = 0;

                    }

                    else

                    {

                        Console.WriteLine("attempted to divide by zero");

                    }

                }

                finally

                {

                    Monitor.Exit(locker);

                }

            }

        }

lock(this) is not a good programming example i will tell more about it another time but for now don’t use it. You must lock a reference variable (please remember structs are value and classes are reference types),

Threading Made Easy

2009-04-21T09:11:00.001-07:00

In the times when all the programming world was not writing database applications; there was an important concept “THREADING”.It may sound hard but actually not that hard.

Firstly a threat is an execution path able to run simultaneously with other threads.

This is how you create a basic thread

 new Thread (TestMethod).Start();

this runs the TestMethodmethod in a new thread.

Thread t = new Thread (TestMethod);

t.Start();

is another way of starting a thread.You can name your thread with t.Name also.

You can stop a thread with Thread.Sleep();

    class ThreadTest

    {

        static void Main()

        {

            Thread t = new Thread(Go);

            Thread b = new Thread(No);

            t.Start();

            t.Join();

            b.Start();

            Console.Read();

        }

        static void Go()

        {

            for (int i = 0; i < 1000; i++)

                Console.Write("X");

        }

        static void No()

        {

            for (int i = 0; i < 1000; i++)

                Console.Write("Y");

        }

    }

thread.join(); waits for the thread to continue

A thread is said to be preempted when its execution is interrupted due to an external factor such as time-slicing. In most situations, a thread has no control over when and where it's preempted.Threads have their own stack but share heap

Passing Data to Threads ;If you want to pass just a single parameter to a thread you can use parameterizedThreadStart

public delegate void ParameterizedThreadStart (object obj);

     
    static void Main()

    {

        Thread t = new Thread(Go);

        Thread b = new Thread(No);

        t.Start("Hi");

        t.Join();

        b.Start();

        Console.Read();

    }

    static void Go(object o)

    {

        for (int i = 0; i < 1000; i++)

            Console.Write(o.ToString());

    }

    static void No()

    {

        for (int i = 0; i < 1000; i++)

            Console.Write("Y");

    }

        }

Ok this is the basics.I will continue with another post.

Hyacinth yet another messenger program

2009-04-21T08:05:00.001-07:00

I started writing another messenger program which in future will have the ability to automatic answering and chating but first version can be used like gtalk.I have a project page at

http://code.google.com/p/hyacinth/

Check it out.

Threading

2009-04-20T07:33:00.001-07:00

A statement is atomic if it executes as a single indivisible instruction.In a 32 bit cpu reading and writing a less than(or equal) 32 bit field is atomic,which can be executed in one instruction,

Reading or writing a 64 bit field is non atomic,the cpu writes the first 32 bit memory and then the second 32 bit memory,if a program reads the first 32 bit while another is writing the second,there can be a bitwise combination of the new and old values.

Lets try if it happens,

     public partial class Form1 : Form

        {

            delegate void SetTextDelegate(string text);

            Int64 number =100000000;

            public Form1()

            {

                InitializeComponent();

            }

            private void AdRichTextBox(string value)

            {

                richTextBox1.Text += value + "\n";

            }

            private void Form1_Load(object sender, EventArgs e)

            {

                Thread j = new Thread(Jam);

                j.Start();

                for (int i = 0; i < 10; i++)

                {

                    Thread t = new Thread(Go);

                    t.Name = "thread" + i.ToString();

                    t.Start();

                    richTextBox1.Text += "thread" + i.ToString() + "started" + "\n";

                }

                richTextBox1.Text += number.ToString();

            }

            public void Go()

            {

                SetTextDelegate spd = new SetTextDelegate(AdRichTextBox);

                    for (int cycles = 0; cycles < 100; cycles++)

                    {

                        number-- ;

                         this.Invoke(spd, new object[] { Thread.CurrentThread.Name + " " + number.ToString()});

                    }

                    doJam = false;

            }

            public bool doJam = true;

            public void Jam()

            {

                while (doJam)

                {

                    Int64 temp = number;

                    number = 0;

                    number = temp;

                }

            }

        }

this is a basic demo Jam method reads the number writes it to a buffer assignes 0 and rewrites buffet to the number, when you run the code we see while the jam writes 0 the go reads the number so it fails.

So here is another example which is famous and good so i will stick with it

Think you write a banking program or an atm program if the same user acceses his account from multiple places and wants to withdraw some money from multiple clients at the same time the first block reads the initial value of bank account the second reads the first takes all money the second thinks money is there the second takes all money too. Lets see in action :

    class Account

        {

            int balance;

            Random r = new Random();

            public Account(int initial)

            {

                balance = initial;

            }

            int Withdraw(int amount)

            {

                if (balance < 0)

                {

                    Console.WriteLine("Negative");

                }

                lock (this)

                {

                if (balance >= amount)

                {

                    Console.WriteLine("Balance before Withdrawal :  " + balance);

                    Console.WriteLine("Amount to Withdraw        : -" + amount);

                    balance = balance - amount;

                    Console.WriteLine("Balance after Withdrawal  :  " + balance);

                    return amount;

                }

                else

                {

                    Console.WriteLine("Not Enough Credit");

                    return 0; // transaction rejected

                }

                }

            }

            public void DoTransactions()

            {

                for (int i = 0; i < 20; i++)

                {

                    Withdraw(r.Next(10, 1000));

                }

            }

        }

        class Test

        {

            public static void Main()

            {

                Thread[] threads = new Thread[10];

                Account acc = new Account(1000);

                for (int i = 0; i < 10; i++)

                {

                    Thread t = new Thread(new ThreadStart(acc.DoTransactions));

                    threads[i] = t;

                }

                for (int i = 0; i < 10; i++)

                {

                    threads[i].Start();

                }

                Console.Read();

            }

        }

if you comment the lock statement you can see how the balance drops to negative values.

I Want a Parliament Blue Gradient ToolStrip

2009-04-18T17:09:00.001-07:00

Actually it is easy make a new Professional Color table like

     class CustomProfessionalColors : ProfessionalColorTable

    {

        public override Color ToolStripGradientBegin

        { get { return Color.SteelBlue; } }

        public override Color ToolStripGradientMiddle

        { get { return Color.DarkBlue; } }

        public override Color ToolStripGradientEnd

        { get { return Color.Black; } }

        public override Color MenuStripGradientBegin

        { get { return Color.Transparent; } }

        public override Color MenuStripGradientEnd

        { get { return Color.Transparent; } }

        public override Color ToolStripBorder

        { get { return Color.Transparent; } }

    }

and use the line

    ToolStripManager.Renderer = new ToolStripProfessionalRenderer(new CustomProfessionalColors());

to make your beatiful tool strip

C# Secret Command

2009-04-18T02:03:00.001-07:00

Yes C# has secret commands which microsoft do not tell us.Here is on of them

     int x = 13;

    TypedReference tRef = __makeref(x);

    int g = __refvalue(tRef,int);

typed references are objects that contain both a managed pointer to a location and a runtime representation of the type that may be stored at that location.

Tips

2009-04-17T01:55:00.000-07:00

Press Ctrl+Space or Alt+RightArrow to auto-complete the word You can use Alt to make vertical selections Ctrl K-C Comment Ctrl K-U uncomment Press Shift+ALT+Enter to use full screen.(Don’t tell me we know all these why are you telling such basic stuff, there is much written here you are only seeing the tip of the iceberg :))

this bloq helps you to write better C# code, I will tell you about c# .net and visual studio performance and optimization also will put a lot of c# articles and algorithms I will write a data service postgre, firebird sql and oracle c# even to string fuctions.This bloq will include image recognition directx xna like topics.But mainly it will be about .net visual studio and c# application applications arraylist asp asp c# aspx c sharp c# c# "classes c# & c# contract c# .net framework c# 2008 c# 3 c# 3.5 c# 4 c# 4.0 c# ado.net c# and c# app.config c# application c# array c# as c# asp.net c# assembly c# basics c# blog c# book c# boxing c# break c# button c# c c# career c# careers c# class c# com c# combobox c# console c# console application c# continue c# controls c# converter c# course c# courses c# database c# datagrid c# dataset c# datetime.now c# define c# development c# dictionary c# dispose c# dll c# dot net c# dotnet c# download c# dropdownlist c# event c# events c# example c# file c# file.exists c# fixed c# for c# for dummies c# form c# forms c# forum c# games c# gettype c# global c# help c# http c# in depth c# indexer c# installer c# interface c# is c# job c# jobs c# keywords c# left c# library c# list find c# listbox c# lists c# listview c# main c# map c# message box c# messagebox c# method c# minor c# mod c# monitor c# namespace c# net c# new c# not c# object c# or c# out c# override c# pdf c# performance c# process.start c# programming c# project c# properties c# property c# readonly c# recruitment c# reference c# regex.replace c# region c# remoting c# right c# samples c# short c# sortedlist c# string c# string.format c# test c# textbox c# this c# thread c# torrent c# training c# treeview c# tuning c# tutorials c# type c# typeof c# types c# using c# var c# vb c# video c# web service c# where c# while c# wiki c# winforms c# work c# xml c#.net c class combobox component csharp database datagrid datalist dataset delegate delegates dll dotnet drop c# dropdownlist foreach hashtable isnumeric learning c# listbox listview mcad mcsd messagebox microsoft .net msdn msdn c# namespace net net framework c# nets programming remoting sample code serializable serialization serialize source code system c# textbox tostring treeview vb vb.net vb.net c# visual basic visual basic .net visual c# visual c# 2008 visual studio visual studio .net visual studio c# winforms xml

Performance Issues

2009-04-16T06:29:00.001-07:00

First of all Microsoft Performance Explorer must not be used to measure execution times or performance comprasion.

I wanted to check the boxing and unboxing performance and tried to use Microsoft Performance Explorer result it sucks try it,you can’t trust its execution times.So i used this code

        1: public static class PerformanceTimer

       2: {

       3:     [DllImport("Kernel32.dll")]

       4:     public static extern void QueryPerformanceCounter(ref long ticks);

       5:  

       6:     static long startTime = 0;

       7:     static long stopTime = 0;

       8:  

       9:     public static void Start()

      10:     {

      11:         QueryPerformanceCounter(ref startTime);

      12:     }

      13:  

      14:     public static void Stop()

      15:     {

      16:         QueryPerformanceCounter(ref stopTime);

      17:     }

      18:  

      19:     public static long Time

      20:     {

      21:         get

      22:         {

      23:             return stopTime - startTime;

      24:         }

      25:     }

      26: }

and got real results,

1-Never use microsoft performance explorer

2-Don’t use boxing it is really 20 times slower

here are my execution times

1636417 ticks used boxing

82530 ticks did not use boxing

       1: class Program

       2: {

       3:  

       4:     static void Main(string[] args)

       5:     {

       6:         Stopwatch sw = new Stopwatch();

       7:         sw.Start();

       8:         PerformanceTimer.Start();

       9:         //ArrayList aList = new ArrayList(1000001);

        //aList.Add(0);

        //for (int i = 0; i < 999999; i++)

        //{

        //    aList.Add(i);

        //    int a = Convert.ToInt32(aList[i]) + 2;

        //    aList[i] = a;

        //}

        List<int> gList = new List<int>(999999);

        for (int i = 0; i < 999999; i++)

        {

            gList.Add(i);

            int a = gList[i] + 2;

            gList[i] = a;

        }

        PerformanceTimer.Stop();

        sw.Stop();

        double ms = (sw.ElapsedTicks * 1000.0) / Stopwatch.Frequency;

        Console.WriteLine(PerformanceTimer.Time.ToString());

        Console.WriteLine(sw.ElapsedMilliseconds.ToString());

        Console.WriteLine(ms.ToString());

        Console.Read();

    }

}

used upper code to test performances, used arraylist as boxing example and used generic list as non boxing.

U can also use System.Diagnostics.Stopwatch;

3- Use Convert to it is better than implicit cast.

4-Use String builder instead of + to build large strings.

5-Use String.Equals instead of == and String.IsNullorEmpty instead of !=.

6-I tested for vs foreach i think there is no difference in execution times.(tested summing an array of 10000 random number previously generated).

CONDITIONAL ATTRIBUTE

2009-04-16T01:03:00.001-07:00

In c# you may need methods which will run when in curtain situations(not like if like when you are testing or in debug mode or in release mode) we use a conditional attribute for this situations.Maybe you have an opening screen in your application and like me you hate losing time,

        1: using System;

       2: using System.Text;

       3: using System.Diagnostics;

       4:  

       5: namespace Master

       6: {

       7:     class Program

       8:     {

       9:         static void Main(string[] args)

        {

            Test t = new Test();

            t.TestA();

            t.TestB();

            t.TestC();

            Console.Read();

        }

    }

     class Test

    {

         public void TestA()

         {

             Console.WriteLine("AAAAA");

         }

         [Conditional("DEBUG")]

         public void TestB()

         {

             Console.WriteLine("BBBBB");

         }

         [Conditional("TEST")]

         public void TestC()

         {

             Console.WriteLine("CCCCC");

         }

  

    }

}

In this example TestA method will always work if you are in debug mode TestB will run and if you add “TEST” to conditional compilation symbols TestC will run.