why 'Windows.UI.Xaml.Markup.XamlParseException' happens when XAML is valid

Question

An exception of type 'Windows.UI.Xaml.Markup.XamlParseException' occurred in myproj.UWP.McgInterop.dll but was not handled in user code

Additional information: The text associated with this error code could not be found.

Cannot find a Resource with the Name/Key category [Line: 0 Position: 0]

Answer 1

You are setting the resource key either from Page.Resources/App.Resources or Standard Resources that has a spelling mistake. Check where you are setting the resources and make sure the spelling is correct. Unfortunately XAML Designer does not show squiggly error when the spelling of resource is incorrect