Get a image of a control even when a control is not visible.

dany_uru

21y3.2kGDI+

I'm looking for a way to get the the image of a control even when it is not visible in screen (for example, when the form is minimized, or the control is under another control). This clasical way to capture screen image is not good : Graphics g1 = myControl.CreateGraphics(); Image myImage = new Bitmap(myControl.Width, myControl.Height, g1); Graphics g2 = Graphics.FromImage(myImage); IntPtr dc1 = g1.GetHdc(); IntPtr dc2 = g2.GetHdc(); BitBlt(dc2, 0, 0, myControl.Width, myControl.Height, dc1, 0, 0, 13369376); g1.ReleaseHdc(dc1); g2.ReleaseHdc(dc2); myImage.Save("c:\\Captured.jpg", ImageFormat.Jpeg); Any idea?? Thanks Daniel

2 Replies

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psy4fun21y ago
Try to use GDI+. Create a new class, inherits the control and add the following method to the new class: public Bitmap GetBitmap() { Bitmap b = new Bitmap(this.ClientRectangle.Width, this.ClientRectangle.Height); Graphics g = Graphics.FromImage(b); PaintEventArgs pe = new PaintEventArgs(g,this.ClientRectangle); base.OnPaint(pe); return b; }
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Tati0821y ago
Hi Daniel, I would also be interested in this isue. I want to keep updating the control, even if it is not visible, or at least save the last controlimage before miminized by the user. I think one of the ways is to use BitBlt, but I have no idea how to give the parameters of the control I want to capture. [DllImport("gdi32.dll",EntryPoint="BitBlt")] public static extern bool BitBlt(IntPtr hdcDest,int xDest, int yDest,int wDest,int hDest,IntPtr hdcSource, int xSrc,int ySrc,int RasterOp); If you found out the solution by now, please let me know, too. Tati
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