你如何延长Bitmap类 [英] How can you extend the Bitmap class

问题描述

我试图扩展位图类，这样我能将我自己的效果的图像。当我用这个code：

I am trying to extend the Bitmap class so that I can apply my own effects to an image. When I use this code:

namespace ImageEditor
{
    public class Effects : System.Drawing.Bitmap

    {
        public void toBlackAndWhite()
        {
            System.Drawing.Bitmap image = (Bitmap)this;
            AForge.Imaging.Filters.Grayscale filter = new AForge.Imaging.Filters.Grayscale();
            this = filter.Apply(this);
        }
    }
}

我收到以下错误：

I get the following error:

'ImageEditor.Effects': cannot derive from sealed type 'System.Drawing.Bitmap'

那么，有没有办法来解决这个问题或者是它根本不可能扩展类？

So is there a way to get around this or is it simply not possible to extend the class?

感谢。

推荐答案

您不能从位图，因为它是密封的派生。

You can't derive from Bitmap because it's sealed.

如果你想添加一个方法Bitmap类，写一个扩展方法：

If you want to add a method to the Bitmap class, write an extension method:

// Class containing our Bitmap extension methods.
public static class BitmapExtension
{
    public void ToBlackAndWhite(this Bitmap bitmap)
    {
        ...
    }
}

然后使用它是这样的：

Then use it like this:

Bitmap bitmap = ...;
bitmap.ToBlackAndWhite();

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