将位图放置在C＃ [英] Placing Bitmap in Canvas in C#

问题描述

可能重复：

我想要的是简单的。我想把 BitmapImage 放入C＃中的 Canvas 中。我的应用程序是基于WPF。我搜索这个，我发现了类似的问题，但我找不到我要找的。

总之，我有这个：

  BitmapImage img = new BitmapImage（new Uri（c：\\xyz.jpg））; 
  

我想把这个放在画布上，意思不是那么重要，矩形等。

解决方案

A BitmapImage Canvas ，因为它不是控件。你可以做的是从 Canvas 中导出自己的类，并覆盖 OnRender（）方法来绘制位图。基本上像这样：

  class CanvasWithBitmap：Canvas 
 {
 public CanvasWithBitmap（）
 {
 _image = new BitmapImage（new Uri（@c：\xyz.jpg））; 
} 
 
 protected override void OnRender（DrawingContext dc）
 {
 dc.DrawImage（_image，
 new Rect（0，0，_image.PixelWidth ，_image.PixelHeight））; 
} 
 
 private BitmapImage _image; 
} 
  

当然，您可能需要公开文件路径和< c $ c> Canvas 通过属性。如果你不想声明自己的类只是为了绘制位图，那么你不能直接使用 BitmapImage 类。显示图片的控制是 Image ，让我们尝试这样：

  BitmapImage bitmap = new BitmapImage（）; 
 bitmap.BeginInit（）; 
 bitmap.UriSource = new Uri（@c：\xyz.jpg）; 
 bitmap.EndInit（）; 
 
 Image image = new Image（）; 
 image.Source = bitmap; 
  

现在你可以把 Image 你想在 Canvas 里面。

Possible Duplicate:
How to render bitmap into canvas in WPF?

What I want is simple. I want to place a BitmapImage into a Canvas in C#. My app is based on WPF. I searched for this and I found similar questions, but I could not find what I'm looking for.

In short, I have this:

BitmapImage img = new BitmapImage(new Uri("c:\\xyz.jpg"));

And I want to put this in the canvas, the mean is not that important, it can be a rectangle or whatever.

解决方案

A BitmapImage object cannot be positioned inside a Canvas because it's not a control. What you can do is to derive your own class from the Canvas and override the OnRender() method to draw your bitmap. Basically something like this:

class CanvasWithBitmap : Canvas
{
    public CanvasWithBitmap()
    {
        _image = new BitmapImage(new Uri(@"c:\xyz.jpg"));
    }

    protected override void OnRender(DrawingContext dc)
    {
        dc.DrawImage(_image,
            new Rect(0, 0, _image.PixelWidth, _image.PixelHeight));
    }

    private BitmapImage _image;
}

Of course you may need to expose the file path and coordinates inside the Canvas through properties. If you do not want to declare your own class just to draw a bitmap then you can't use the BitmapImage class directly. The control to display images is Image, let's try this:

BitmapImage bitmap = new BitmapImage();
bitmap.BeginInit();
bitmap.UriSource = new Uri(@"c:\xyz.jpg");
bitmap.EndInit();

Image image = new Image();
image.Source = bitmap;

Now you can put the Image control where you want inside the Canvas.

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