How does the Visual Studio debugger decide what values ​​can be viewed using the Text / XML / HTML Visualizer?

Question

I noticed that when I look at variables of certain types, for example XElement , in the viewport in Visual Studio, if I click on the magnifying glass of Debug Visualizer, the same visualizers will appear that apply to strings (text, XML, HTML). I have not seen this before. How did the debugger decide to do this?

EDIT: here is a screenshot from the Clock window demonstrating that XElement will be displayed using Text Visualizer, and System.Version (which also implements ToString) will not.

Answer 1

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http://msdn.microsoft.com/en-us/library/vstudio/bb162331 (v = vs .100).aspx http://msdn.microsoft.com/en-us/library/vstudio/bb146621 (v = vs .100).aspx

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Answer 2

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