private   void  pictureBox1_Click（  object  sender，EventArgs e）
 {
 Point topLeft = PointToScreen（ new  Point （pictureBox1.Left，pictureBox1.Top））; 
 int  x = MousePosition.X  -  topLeft.X; 
 int  y = MousePosition.Y  -  topLeft.Y; 

 MessageBox.Show（ string  .Format（  X {0} Y {1}，x，y））; 
} 

因此，请使用PointToScreen在屏幕内查找图片框的坐标。

问题在于：你提到位图坐标，并没有提到要点击的内容。如果我们假设这是点击 PictureBox ，则像素坐标与此控件的坐标完全相同。就这样。



（如果您的控件不同（但为什么？），您可以重新计算坐标平移投影屏幕坐标或考虑控件的位置。）



现在，使用 PictureBox 是值得怀疑的。它可能有用，也可能没有用，但通常不会：它会在没有任何帮助的情况下造成麻烦，只会占用额外的资源，甚至会花费更多的开发时间。请查看我过去的答案：

在其中附加图片图片框 [ ^ ]，

画一个矩形C＃ [ ^ ]，

如何从旧图纸中清除面板 [ ^ ]。

-SA

I have a picturebox,I could get the mouse's (x,y) from mouse double click event ,but how to conver the (x,y) to bitmap's real (x,y)?

private void pictureBox1_Click(object sender, EventArgs e)
{
  Point topLeft = PointToScreen(new Point(pictureBox1.Left, pictureBox1.Top));
  int x = MousePosition.X - topLeft.X;
  int y = MousePosition.Y - topLeft.Y;

  MessageBox.Show(string.Format("X{0} Y{1}", x, y));
}

So use PointToScreen to find the coordinates of the picturebox within the screen.

Here is the problem: you mention "bitmap coordinates", and don't mention what to click on. If we assume that this is a click on a PictureBox, the pixel coordinates are exactly the same as the coordinates of this control. That's all.

(If your control is different (but why?), you can re-calculate the coordinate translation throw screen coordinates or taking into account control's locations.)

Now, using PictureBox is questionable. It may or may not be useful, but usually not: it creates hassles without any help, only eats additional resources and even more of your development time to be spent for nothing. Please see my past answers:
Append a picture within picturebox[^],
draw a rectangle in C#[^],
How do I clear a panel from old drawing[^].

—SA