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Callbacks problems

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Join Date: Dec 2004

Posts: 489

Reputation: Acidburn is an unknown quantity at this point

Solved Threads: 5

Acidburn

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Posting Pro in Training

Callbacks problems

Apr 8th, 2009

Hey guys,

I've got a multithreaded application. The GUI runs on its own thread whilst a background worker thread will get invovked later on. Now the problem occurs when the bakground thread trys to manipulate the GUI thread.

Solution is a callback using invokeRequired.

 Help with Code Tags 
 C# Syntax (Toggle Plain Text) 
public void ThreadProcSafe2(String text)
        {
            if (this.m_AllKnownDevicesFrm.InvokeRequired)
            {
                // It's on a different thread, so use Invoke.
                SetTextCallback3 d = new SetTextCallback3(switchPanels);
                this.Invoke(d, new object[] {1} );
 
            }
            else
            {
                switchPanels(1);
            }
        }
public void ThreadProcSafe2(String text)
        {
            if (this.m_AllKnownDevicesFrm.InvokeRequired)
            {
                // It's on a different thread, so use Invoke.
                SetTextCallback3 d = new SetTextCallback3(switchPanels);
                this.Invoke(d, new object[] {1} );
                
            }
            else
            {
                switchPanels(1);
            }
        }

But this fails when its running... With error of

•

"invalid parameter"

switchPanels is a method declared to take an int has an agrument.

Confused. Can anyone shread any light onto this problem?

Thanks guys...

•

Join Date: Aug 2008

Posts: 1,160

Reputation: dickersonka will become famous soon enough

Solved Threads: 137

dickersonka dickersonka is offline

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Veteran Poster

Re: Callbacks problems

Apr 8th, 2009

try this

its unclear why you are using string text as a parameter if its not being passed on, but here it is

 Help with Code Tags 
 C# Syntax (Toggle Plain Text) 
void delegate textCallback(string text);
public void ThreadProcSafe2(String text)
        {
            if (this.m_AllKnownDevicesFrm.InvokeRequired)
            {
                this.m_AllKnownDevicesFrm.Invoke(new textCallback(ThreadProcSafe2), text);                
            }
            else
            {
                switchPanels(1);
            }
        }
void delegate textCallback(string text);
public void ThreadProcSafe2(String text)
        {
            if (this.m_AllKnownDevicesFrm.InvokeRequired)
            {
                this.m_AllKnownDevicesFrm.Invoke(new textCallback(ThreadProcSafe2), text);                
            }
            else
            {
                switchPanels(1);
            }
        }