How to invoke WPF Dispatcher in Nunit?
I want to test an application which renders a text block with a data field value. I would like to get the actual width and actual height, once the rendering completes. Everything works fine. The problem came first, when I tried to test the application. I'm unable to invoke the dispatcher from the test project.
Following is the code.
this.Loaded += (s, e) =>
{
TextBlock textBlock1 = new TextBlock();
//// Text block value is assigned from data base field.
textBlock1.Text = strValueFromDataBaseField;
//// Setting the wrap behavior.
textBlock1.TextWrapping = TextWrapping.WrapWithOverflow;
//// Adding the text block to the layout canvas.
this.layoutCanvas.Children.Add(textBlock1);
this.Dispatcher.BeginInvoke(DispatcherPriority.Background,
(Action)(() =>
{
开发者_JS百科 //// After rendering the text block with the data base field value. Measuring the actual width and height.
this.TextBlockActualWidth = textBlock1.ActualWidth;
this.TextBlockActualHeight = textBlock1.ActualHeight;
//// Other calculations based on the actual widht and actual height.
}
));
};
I've just started using the NUnit. So, please help me.
Thanks
You might want to look at http://www.codeproject.com/KB/WPF/UnitTestDispatcherTimer.aspx
It deals with a DispatcherTimer
in WPF and NUnit which in turn uses the Dispatcher
.
Edit
From the link try and do this before your test:
Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Normal, testMethod);
// Start the worker thread's message pump
Dispatcher.Run(); // This will block until the dispatcher is shutdown
And stop it after the test.
Dispatcher disp = Dispatcher.CurrentDispatcher;
// Kill the worker thread's Dispatcher so that the
// message pump is shut down and the thread can die.
disp.BeginInvokeShutdown(DispatcherPriority.Normal);
I haven't used nUnit to write unit tests before, but this is a common problem with VS unit tests. What can end up happening is that each test uses a different dispatcher and WPF requires you to use the same dispatcher. To get around this, create a static class to cache the Dispatcher and then invoke everything through it.
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