CODEWITHSUNDEEP
c#.net-3.5multithreadingbegininvoke
Odys
Odys

Reputation: 9090

InvalidOperationException within BeginInvoke

I am getting an InvalidOperationException with message Cross-thread operation not valid..

The _waitForm is created in the constructor of the main form. The method in the screenshot gets called from another thread. I though this is what BeginInvoke solves. I know that I am accessing the form from another thread than the one created. Any ideas on how to solve this?

enter image description here

Here is the stacktrace:

   at System.Windows.Forms.Control.get_Handle()
   at System.Windows.Forms.Control.get_ContainsFocus()
   at System.Windows.Forms.Control.SelectNextIfFocused()
   at System.Windows.Forms.Control.SetVisibleCore(Boolean value)
   at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
   at System.Windows.Forms.Control.Hide()
   at YYYYYY.Boundary.ZzzzzForm.<HideWaitForm>b__c() in R:\Projects\XXXX\trunk\src\YYYYYY\Boundary\ZzzzzForm.cs:line 514
   at System.Windows.Forms.Control.InvokeMarshaledCallbackDo(ThreadMethodEntry tme)
   at System.Windows.Forms.Control.InvokeMarshaledCallbackHelper(Object obj)
   at System.Threading.ExecutionContext.runTryCode(Object userData)
   at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Windows.Forms.Control.InvokeMarshaledCallback(ThreadMethodEntry tme)
   at System.Windows.Forms.Control.InvokeMarshaledCallbacks()

sorry for the screenshot, I wanted to show the whole picture

Upvotes: 2

Views: 1212

Answers (2)

Odys
Odys

Reputation: 9090

I've found it. Of course it was my mistake!

The opposite of that method is the one showing the _waitForm. I had mistakenly called _waitForm.Show() from another than the UI thread without invokation. Strangely, this was able to succeed and caused this exception (that has the wrong message).

Upvotes: 0

e_ne
e_ne

Reputation: 8469

Have you tried to operate on _waitForm through:

_waitForm.Invoke(new MethodInvoker(_waitForm.Hide));

Alternatively, if the above doesn't work:

_waitForm.Invoke(new MethodInvoker(() => 
{
    _waitForm.Reset();
    _waitForm.Hide();
}));

Upvotes: 3

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