Comments on: Taking WPF “Screenshots”

By: WPF UIElement extension methods for ’screenshot’ and location

WPF UIElement extension methods for ’screenshot’ and location — Tue, 20 Apr 2010 12:37:33 +0000

[...] a bunch of WPF pages. In WPF this is an easy task. Especially when somenone already has created an extension method for it:. The extension method is in C#, so i have converted it to VB.NET and added another extension method [...]

By: Kenneth

Kenneth — Mon, 05 Apr 2010 20:28:00 +0000

Excellent post! Solves what I needed to do (which is to screen capture the WPF window).
Thank you!

By: Aaron

Aaron — Wed, 03 Feb 2010 19:18:39 +0000

I used a style for the TabControl and set the TabPanel’s FlowDirection to RightToLeft to get the tabs on the right. Then I left the FlowDirection of the TabControl itself as LeftToRight. Here’s the TabPanel tag that I have within the ControlTemplate:

By: Aaron

Aaron — Wed, 03 Feb 2010 13:59:06 +0000

I gave that a try this morning, but didn’t have any luck with it. When I figure out a solution, I’ll be sure to post it. Thanks for your suggestion!

By: srobbins

srobbins — Tue, 02 Feb 2010 20:20:11 +0000

I haven’t tested it, but you could possibly create a grid (or another container), set the flow direction, add your user control to it and screenshot the grid. Then re-parent the user control back where it came from.

By: Aaron

Aaron — Tue, 02 Feb 2010 19:21:33 +0000

Thank you very much for the code sample – it’s excellent! One question – I’m loading a usercontrol into a tabcontrol with a FlowDirection of RightToLeft and when the code grabs the screenshot of the usercontrol, it’s always backwards as a result of the tabcontrol’s flow layout. Any ideas how to get around that?

By: srobbins

srobbins — Sun, 27 Dec 2009 08:44:44 +0000

Haven’t got a clue I’m afraid. If you put the sample code somewhere I can try it here to see if it’s a “your machine” issue if that’s any help.

By: Kess

Kess — Wed, 23 Dec 2009 15:35:59 +0000

I am getting the COMException as well. Does any one know of a solution? Thanks.

By: AAron

AAron — Tue, 24 Nov 2009 19:45:34 +0000

Very nice, thank you for posting. Saved lots of time here too.

By: Moritz

Moritz — Thu, 08 Oct 2009 10:56:13 +0000

Thanks a lot for this great piece of code! Saved me a lot of research.

Best regards from Germany

By: srobbins

srobbins — Mon, 20 Apr 2009 07:17:33 +0000

@cristi Good question, I have no idea If the Window itself is invisible, and isn’t rendering, then you could always render whatever “root” content you have in there (grid, stackpanel, canvas etc.)

By: cristi

cristi — Fri, 17 Apr 2009 13:13:55 +0000

Excelent post!

But how it works if the UIElement is not visible? Taking screenshot from a hidden windows

By: Prerak Sanghvi

Prerak Sanghvi — Fri, 20 Mar 2009 15:22:15 +0000

This repeatably causes low level exceptions on my machine (as you read the stack trace, know that I’ve ensured my code runs on UI thread). I’m using .NET 3.0 (I know I could update, but I have other constraints).

Unhandled Exception on Dispatcher (System.Windows.Threading.Dispatcher). Handled=False, Exception=System.Runtime.InteropServices.COMException (0x8000FFFF): Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))
at MS.Internal.HRESULT.Check(Int32 hr)
at System.Windows.Media.Composition.DUCE.Channel.SendCommand(Byte* pCommandData, Int32 cSize)
at System.Windows.Media.Composition.DUCE.CompositionNode.SetAlpha(ResourceHandle hCompositionNode, Double alpha, Channel channel)
at System.Windows.Media.Visual.DisconnectBitmapEffectPropertiesOnAllChannels()
at System.Windows.Media.Visual.set_VisualBitmapEffect(BitmapEffect value)
at System.Windows.UIElement.OnBitmapEffectChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
at System.Windows.DependencyObject.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, OperationType operationType)
at System.Windows.DependencyObject.InvalidateProperty(DependencyProperty dp)
at System.Windows.StyleHelper.InvalidateDependents(Style ownerStyle, FrameworkTemplate frameworkTemplate, DependencyObject container, DependencyProperty dp, FrugalStructList`1& dependents, Boolean invalidateOnlyContainer)
at System.Windows.StyleHelper.OnTriggerSourcePropertyInvalidated(Style ownerStyle, FrameworkTemplate frameworkTemplate, DependencyObject container, DependencyProperty dp, DependencyPropertyChangedEventArgs changedArgs, Boolean invalidateOnlyContainer, FrugalStructList`1& triggerSourceRecordFromChildIndex, FrugalMap& propertyTriggersWithActions, Int32 sourceChildIndex)
at System.Windows.FrameworkElement.OnPropertyChanged(DependencyPropertyChangedEventArgs e)
at System.Windows.DependencyObject.NotifyPropertyChange(DependencyPropertyChangedEventArgs args)
at System.Windows.DependencyObject.UpdateEffectiveValue(EntryIndex entryIndex, DependencyProperty dp, PropertyMetadata metadata, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, Boolean coerceWithDeferredReference, OperationType operationType)
at System.Windows.DependencyObject.SetValueCommon(DependencyProperty dp, Object value, PropertyMetadata metadata, Boolean coerceWithDeferredReference, OperationType operationType, Boolean isInternal)
at System.Windows.DependencyObject.SetValue(DependencyPropertyKey key, Object value)
at System.Windows.DependencyObject.SetValue(DependencyPropertyKey dp, Boolean value)
at System.Windows.ReverseInheritProperty.FirePropertyChangeInAncestry(DependencyObject element, Boolean oldValue, DeferredElementTreeState treeState)
at System.Windows.ReverseInheritProperty.FirePropertyChangeInAncestry(DependencyObject element, Boolean oldValue, DeferredElementTreeState treeState)
at System.Windows.ReverseInheritProperty.FirePropertyChangeInAncestry(DependencyObject element, Boolean oldValue, DeferredElementTreeState treeState)
at System.Windows.ReverseInheritProperty.FirePropertyChangeInAncestry(DependencyObject element, Boolean oldValue, DeferredElementTreeState treeState)
at System.Windows.ReverseInheritProperty.OnOriginValueChanged(DependencyObject oldOrigin, DependencyObject newOrigin, DeferredElementTreeState& oldTreeState)
at System.Windows.Input.MouseDevice.ChangeMouseOver(IInputElement mouseOver, Int32 timestamp)
at System.Windows.Input.MouseDevice.PreNotifyInput(Object sender, NotifyInputEventArgs e)
at System.Windows.Input.InputManager.ProcessStagingArea()
at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)

By: srobbins

srobbins — Fri, 16 Jan 2009 19:10:30 +0000

The only other suggestion I can think of is to render to a WritableBitmap (WriteableBitmap rb = new WriteableBitmap(renderTarget);) then try grabbing the pixels from that. You will need to find another library to encode the data though, unless you want to move it around in a raw format.

By: abi

abi — Fri, 16 Jan 2009 06:50:58 +0000

Thanks srobbins for the reply , Encoders wont work in partial trust, do you have any suggetions to take the bytes of RenderTargetBitmap, im really stuck here.

Thanks

By: srobbins

srobbins — Thu, 15 Jan 2009 20:03:50 +0000

@abi I’ve just had a look through, and it won’t work in partial trust because of the JpegBitmapEncoder – it’s not supported in that situatation. I guess it’s to stop you creating a bitmap on the fly and bypassing the security for where you can and can’t grab images from.

By: abi

abi — Thu, 15 Jan 2009 08:10:57 +0000

Very good post, i too had the same problem, however when i published my xbap application under partial trust, it throw a Security Exception, Is DrawingVisual and DrawingContext will work only on full trust,

Thank Your