Problem in acquiring screenshot from Clipboard

[Penzium]

Hi,

for an application I need to acquire timed screenshot. I wrote a VI based on the example that I found at this link: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019NdrSAE&l=it-IT the VI is attacched in this post.

The problem is that I have success in triggering the event keybd_event so I have the image in the clipboard (if I copy the image in paint the screenshot is acquired correctly) but when I call the Invoke Node Clipboard->GetImage this returns an empty reference and so I have an error in saving file. It seems that clipboard is empty but it is not true.

Someone could help me? Why do I have this behavior?

Thank you very much. 

[StevenD · Accepted solution]

I think the dll and the .NET calls have to run in the UI thread. Go to the VI properties -> Execution and change "Preferred Execution System" to "User Interface"

[Penzium]

It works! Thank you very much for your feedback!