VB.NET Bitmap.Save Works Once

Question

I have a function that gets a screenshot, saves it, and returns the file name to the image. I'm using the Bitmap.Save method and I think I'm cleaning up after myself. It, however, works only once--if the user calls the routine another time I get a external exception with a very helpful "A generic error occurred in GDI+" message.

It can save to the directory that one time (permissions don't seem to be the problem). And, if I change the file name (with, say, a simple counter) it works all the time--just leaves a mess in the temp directory in my opinion.

I've read some MSDN articles that lead me to believe I think I'm leaving a lock on the file, but 'no idea what I'm doing incorrectly.

Here's the code:

Function GetImage()

    Dim tempFile As String = Path.GetTempPath() & "Screen_Log.jpg"

    Me.WindowState = FormWindowState.Normal
    Me.Activate()
    Me.Refresh()

    Dim bmpScreenshot As Bitmap = New Bitmap(Width, Height, PixelFormat.Format32bppArgb)
    Dim gfxScreenshot As Graphics = Graphics.FromImage(bmpScreenshot)

    gfxScreenshot.CopyFromScreen(Me.Location.X, Me.Location.Y, 0, 0, Me.Size, CopyPixelOperation.SourceCopy)

    ' *** Works once, then crashes here.
    bmpScreenshot.Save(tempFile, ImageFormat.Jpeg)

    bmpScreenshot.Dispose()
    gfxScreenshot.Dispose()

    Return tempFile

End Function

Any suggestions?

-Gnerf

Answer 1

Bitmaps can be very sticky. Try this and see if it fixes the issue. Try without the GC part and see if the using block are enough - otherwise add the garbage collection calls.

Function GetImage() As String
 Dim tempFile As String = Path.GetTempPath() & "Screen_Log.jpg"
 Using bmpScreenshot As Bitmap = New Bitmap(Width, Height, PixelFormat.Format32bppArgb)
  Using gfxScreenshot As Graphics = Graphics.FromImage(bmpScreenshot)
   gfxScreenshot.CopyFromScreen(Me.Location.X, Me.Location.Y, 0, 0, Me.Size, CopyPixelOperation.SourceCopy)
   bmpScreenshot.Save(tempFile, ImageFormat.Jpeg)
  End Using
 End Using
 GC.Collect()
 GC.WaitForPendingFinalizers()
 GC.Collect()
 Return tempFile
End Function