在C＃代碼中實現線程

Question

我想創建兩個線程，因爲我想先將循環分成兩部分。而不是for (var row = 0; row < area.Height; row++)我想爲我想要線程的每個循環制作for (var row = 0; row < area.Height/2; row++)和for (var row = area.Height/2; row < area.Height; row++)。我不知道如何實現這個東西。你可以幫我嗎 ？

using System; 
using System.Diagnostics; 
using System.Drawing; 
using System.Threading; 

namespace MandelbrotGenerator { 
    public class SyncImageGenerator : IImageGenerator { 
    public void GenerateImage(Area area) { 
     var sw = Stopwatch.StartNew(); 
     var bitmap = SyncImageGenerator.GenerateSyncroniously(area); 
     GenerationDone(area, bitmap, sw.Elapsed); 
    } 

    public static Bitmap GenerateSyncroniously(Area area) { 
     int maxIterations; 
     double zBorder; 
     double cReal, cImg, zReal, zImg, zNewReal, zNewImg; 

     maxIterations = Settings.DefaultSettings.MaxIterations; 
     zBorder = Settings.DefaultSettings.ZBorder * Settings.DefaultSettings.ZBorder; 

     Bitmap bitmap = new Bitmap(area.Width, area.Height); 

     for (var row = 0; row < area.Height; row++) { 
     for (var col = 0; col < area.Width; col++) { 
      var pixelWidth = (area.MaxReal - area.MinReal)/area.Width; 
      cReal = area.MinReal + col * pixelWidth; 
      var pixelHeight = (area.MaxImg - area.MinImg)/area.Height; 
      cImg = area.MinImg + row * pixelHeight; 
      zReal = 0.0; 
      zImg = 0.0; 
      var iter = 0; 
      while (zReal*zReal+zImg*zImg<zBorder && iter<maxIterations) { 
      zNewReal = zReal * zReal - zImg * zImg; 
      zNewImg = zImg * zReal + zReal * zImg; 
      zNewReal = zNewReal + cReal; 
      zNewImg = zNewImg + cImg; 
      zReal = zNewReal; 
      zImg = zNewImg; 
      iter++; 
      } 
      bitmap.SetPixel(col, row, ColorSchema.GetColor(iter)); 
     } 
     } 

     return bitmap; 
    } 
    public event EventHandler<EventArgs<Tuple<Area, Bitmap, TimeSpan>>> ImageGenerated; 
    private void GenerationDone(Area area, Bitmap bitmap, TimeSpan time) { 
     if (ImageGenerated != null) { 
     ImageGenerated(this, new EventArgs<Tuple<Area, Bitmap, TimeSpan>>(Tuple.Create(area, bitmap, time))); 
     } 
    } 
    } 
} 

其實，我不知道如何使用所有這些變量以及如何使用2個線程共享所有這些變量。

Answer 1

當有足夠多的抽象可供選擇時，不要直接使用線程。 TPL是其中之一，但我更喜歡微軟的Reactive Framework（NuGet「Rx-Main」）。有了它，你可以這樣做：

public static IObservable<Bitmap> GenerateAsynchronously(Area area) 
{ 
    int maxIterations = 100; 
    double zBorder = 1.0; 

    var compute = 
     from row in Observable.Range(0, area.Height) 
     from col in Observable.Range(0, area.Width) 
     from iter in Observable.Start(() => 
     { 
      var pixelWidth = (area.MaxReal - area.MinReal)/area.Width; 
      double cReal = area.MinReal + col * pixelWidth; 
      var pixelHeight = (area.MaxImg - area.MinImg)/area.Height; 
      double cImg = area.MinImg + row * pixelHeight; 
      double zReal = 0.0; 
      double zImg = 0.0; 
      var i = 0; 
      while (zReal * zReal + zImg * zImg < zBorder && i < maxIterations) 
      { 
       double zNewReal = zReal * zReal - zImg * zImg; 
       double zNewImg = zImg * zReal + zReal * zImg; 
       zNewReal = zNewReal + cReal; 
       zNewImg = zNewImg + cImg; 
       zReal = zNewReal; 
       zImg = zNewImg; 
       i++; 
      } 
      return i; 
     }) 
     select new { row, col, iter }; 

    var query = 
     from xs in compute.ToArray() 
     from bm in Observable.Start(() => 
     { 
      Bitmap bitmap = new Bitmap(area.Width, area.Height); 
      foreach (var x in xs) 
      { 
       bitmap.SetPixel(x.col, x.row, ColorSchema.GetColor(x.iter)); 
      } 
      return bitmap; 
     }) 
     select bm; 

    return query; 
} 

您現在正在返回一個IObservable<Bitmap>，而不是Bitmap。你這樣消費：

var bitmapObservable = SyncImageGenerator.GenerateAsynchronously(area); 
    bitmapObservable 
     .Subscribe(bitmap => 
     { 
      GenerationDone(area, bitmap); 
     }); 

根本沒有必要管理線程，但你得到最大的併發性。