绘图图形在VB.net中消失 [英] Drawing Graphics Disappear in VB.net

问题描述

我有一个简单的程序，可以用FillEllipse和FillRectangle在屏幕上绘制。我的问题是，当您将另一个窗口拖过屏幕的一小部分时，该部分将被擦除。当您拖动另一个窗口时，发生这种情况，松手并将其拖回。有什么方法可以解决这个问题？

  Dim MyFormObject As Graphics = Me.CreateGraphics 
选择案例形状
 CaseEllipse
 MyFormObject.FillEllipse（brush，eX  -  CInt（brushWidth / 2），eY  -  CInt（brushHeight / 2），brushWidth，brushHeight）
 CaseRectangle
 MyFormObject .FillRectangle（刷子，eX-CInt（brushWidth / 2），eY-CInt（brushHeight / 2），brushWidth，brushHeight）
结束选择
  

解决方案

您可以将一个PictureBox控件放在窗体上并绘制到该窗体上，并且在其他窗口绘制时不会被删除：

在form_load上执行一次操作：

  pictureBox1。图片=新的位图（宽度，高度）; b 
 
 
 
 
 
  Graphics.FromImage（pictureBox1.Image）.FillRectangle（Brushes.Black，0，0，100，100）; 
 pictureBox1.Refresh（）; 
  




I have a simple program that you can draw on the screen with FillEllipse and FillRectangle. My problem is that when you drag another window over even a small portion of the screen, that part will be erased. This happens when you drag the other window over, let go, and drag it back off. Is there any way to fix this?

Dim MyFormObject As Graphics = Me.CreateGraphics
        Select Case shape
            Case "Ellipse"
                MyFormObject.FillEllipse(brush, e.X - CInt(brushWidth / 2), e.Y - CInt(brushHeight / 2), brushWidth, brushHeight)
            Case "Rectangle"
                MyFormObject.FillRectangle(brush, e.X - CInt(brushWidth / 2), e.Y - CInt(brushHeight / 2), brushWidth, brushHeight)
        End Select

解决方案

You can put a PictureBox control on your form and draw to that instead and it won't be erased when other windows paint over it:

do this once, on form_load or something:

pictureBox1.Image = new Bitmap(Width, Height);

to draw:

Graphics.FromImage(pictureBox1.Image).FillRectangle(Brushes.Black, 0, 0, 100, 100);
pictureBox1.Refresh();

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