Silverlight 3: No change, but now I get "Page not found"

Question

There was a page that worked fine. The only change I made was to add a datagrid to the page (which also added xmlns), and suddenly I get the page not found. Check out UriMappings. Tried the default link by default. There is no joy.

Ideas?

UPDATE: the answer was that I had a mock class that did not initialize the collection. See Byrant's answer for some time.

Answer 1

To find out what the problem is, you need to make one change to your MainPage.xaml.cs:

// If an error occurs during navigation, show an error window
private void ContentFrame_NavigationFailed(object sender, NavigationFailedEventArgs e)
{
    Exception ex = e.Exception;

    while (ex.InnerException != null)
    {
        ex = ex.InnerException;
    }

    e.Handled = true;
    ChildWindow errorWin = new ErrorWindow(ex);
    errorWin.Show();
}

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Answer 2

Firebug , , ... devServer ,