A generic error occured in GDI+

[lidds]

I have some code that takes a screen capture of my monitor. This code seems to work perfectly OK and can take multiple screen captures, apart from when I do a Print Screen using the keyboard or open SnagIT 8, when I then try to run my code again I get an error "A generic error occured in GDI+"

I am at a bit of a loss, I have had a look on the internet, but everything I seem to find appears to be related to web apps. and access permissions. This is a window based application and therefore can not seem to find an answer.

Below is the code I am running:

Public Function CaptureWindow(ByVal handle As IntPtr) As Image
        Dim SRCCOPY As Integer = &HCC0020
        ' get te hDC of the target window
        Dim hdcSrc As IntPtr = User32.GetWindowDC(handle)
        ' get the size
        Dim windowRect As New User32.RECT
        User32.GetWindowRect(handle, windowRect)
        Dim width As Integer = windowRect.right - windowRect.left
        Dim height As Integer = windowRect.bottom - windowRect.top
        ' create a device context we can copy to
        Dim hdcDest As IntPtr = GDI32.CreateCompatibleDC(hdcSrc)
        ' create a bitmap we can copy it to,
        ' using GetDeviceCaps to get the width/height
        Dim hBitmap As IntPtr = GDI32.CreateCompatibleBitmap(hdcSrc, width, height)
        ' select the bitmap object
        Dim hOld As IntPtr = GDI32.SelectObject(hdcDest, hBitmap)
        ' bitblt over
        GDI32.BitBlt(hdcDest, 0, 0, width, height, hdcSrc, 0, 0, SRCCOPY)
        ' restore selection
        GDI32.SelectObject(hdcDest, hOld)
        ' clean up 
        GDI32.DeleteDC(hdcDest)
        User32.ReleaseDC(handle, hdcSrc)
 
        ' get a .NET image object for it
        Dim img As Image = Image.FromHbitmap(hBitmap)
        ' free up the Bitmap object
        GDI32.DeleteObject(hBitmap)
 
        Return img
    End Function 'CaptureWindow

The line of code that gives the error is:

Dim img As Image = Image.FromHbitmap(hBitmap)

Below is also the stack trace:

at System.Drawing.Image.FromHbitmap(IntPtr hbitmap, IntPtr hpalette)
at System.Drawing.Image.FromHbitmap(IntPtr hbitmap)
at ReviewInsight.ScreenCapture.CaptureWindow(IntPtr handle) in E:\Ticodi Software\ReviewInSight\ScreenCapture.vb:line 38
at ReviewInsight.ScreenCapture.CaptureScreen() in E:\Ticodi Software\ReviewInSight\ScreenCapture.vb:line 10
at ReviewInsight.ScreenCapture.CaptureDeskTopRectangle(Rectangle CapRect, Int32 CapRectWidth, Int32 CapRectHeight) in E:\Ticodi Software\ReviewInSight\ScreenCapture.vb:line 59
at ReviewInsight.frmCommManager.captureScreen() in E:\Ticodi Software\ReviewInSight\frmCommManager.vb:line 2824
at ReviewInsight.frmMain.btnCapture_Click(Object sender, EventArgs e) in E:\Ticodi Software\ReviewInSight\frmMain.vb:line 1963
at DevComponents.DotNetBar.BaseItem.RaiseClick(eEventSource source)
at DevComponents.DotNetBar.BaseItem.InternalMouseUp(MouseEventArgs objArg)
at DevComponents.DotNetBar.PopupItem.InternalMouseUp(MouseEventArgs objArg)
at DevComponents.DotNetBar.ButtonItem.InternalMouseUp(MouseEventArgs objArg)
at DevComponents.DotNetBar.BaseItem.InternalMouseUp(MouseEventArgs objArg)
at DevComponents.DotNetBar.ItemContainer.InternalMouseUp(MouseEventArgs objArg)
at DevComponents.DotNetBar.ItemControl.OnMouseUp(MouseEventArgs e)
at DevComponents.DotNetBar.RibbonBar.OnMouseUp(MouseEventArgs e)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.ContainerControl.WndProc(Message& m)
at DevComponents.DotNetBar.ItemControl.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.Run(ApplicationContext context)
at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)
at ReviewInsight.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

Any help that anyone can give me would be really apreshiated

Thanks in advance

Simon

 

[Haxaro]

I dont want to come off as harsh, but if you are going to distribute this program, i dont think that many people will take a screen shot, or open SnagIt 8.

If you have just made this for personal use, then yes it may be a problem, and no i do not have an answer.

Sorry

 

[JohnH]

see my reply in this thread about how you can get rid of most of the problematic API calls: http://www.vbdotnetforums.com/graphics-gdi/32938-including-mouse-screenshot.html

 

[thirteentwenty]

The code that is mentioned in JohnH's post had/has that same issue I found that it was due to a timer issue. I'm not sure how you're firing your function (via button or if it's a timed thing) but if it is the later heres how I figured it out

First I modified my clean up routine, specifically commented the line where I remove the temp image (I'm going out on a limb here and guessing that your app for doing screenshots and mine are for totally different purposes).

Second I stepped back my timer by 100ms increments.

EDIT: it seems that we have stumbled upon the same tutorial for doing screen captures, please take JohnH's advice and look at this post, then try what I did... mind you that my code gets the active window.