Question

I am trying to use threadsafe calls to UI controls from a C# form. For some reason the BackgroundWorkerHelper is not available, might be because of the version of C# or becuase I am deploying to a “Window CE 5.0 Device”.

I have this

    //For ThreadSafe called to edit components
    private delegate void SetControlPropertyThreadSafeDelegate(Control control, string propertyName, object propertyValue);
    public static void SetControlPropertyThreadSafe(Control control, string propertyName, object propertyValue)
    {
        if (control.InvokeRequired)
        {
            control.Invoke(new SetControlPropertyThreadSafeDelegate(SetControlPropertyThreadSafe), new object[] { control, propertyName, propertyValue });
        }
        else
        {
            control.GetType().InvokeMember(propertyName, BindingFlags.SetProperty, null, control, new object[] { propertyValue });
        }

    }

And am calling the Thread like this

private Thread workerThread = new Thread(new ThreadStart(this.remoteRequestBackgroundTask));

workerThread.Start();

Then inside the remoteRequestBackgroundTask() function I change controls like this

        //enable the cancel button
        SetControlPropertyThreadSafe(btnCancel, "Enabled", true);

The problem is that when it runs, debugging stops here

control.GetType().InvokeMember(propertyName, BindingFlags.SetProperty, null, control, new object[] { propertyValue });

and I get “NotSupportedException”

Answer 1

Have a look at the MSDN Documentation for .InvokeMember, under Exceptions. Next to NotSupportedException, you’ll see:

The .NET Compact Framework does not currently support this method.

In that else block, I believe you could do something like this instead. This is shortened from some very similar .NET Compact Framework code I have:

PropertyInfo propertyInfo = control.GetType().GetProperty(propertyName);
propertyInfo.SetValue(control, propertyValue, null);