Visualized expression in custom data visualizer

8
votes

When I choose one of the built-in visualizers:

Choosing a visualizer

I can see the original expression being visualized:

Text visualizer, with circled visualized expression

How can I get this information from within my own custom visualizer?

I've looked through the API reference, without finding anything.

(If you haven't found an answer, please upvote the request to support this on Developer Community.)

Update

The linked Developer Community request has been closed for reasons.

1
c#.netvb.netvisual-studiovisualizer
A few years ago, I asked the PM of the Visual Studio Debugger the same question in the comments in of one of his blog posts - his answer was "It's not possible to retrieve this information in a custom visualizer". So, it is quite probable that this has not changed - even in VS2019 where the mechanism was modified to work with .Net Core. - frank koch
@frankkoch Do you have a link to this back-and-forth? - Zev Spitz

1 Answers

2
votes

Because you were interested in a hyperlink, I searched my email archive and found a mail from February 04, 2006 (well, this is bit more than 'a few years ago'):

My question was:

... I also would like to know how the Visualizers provided by VS2005 manage to display the expression (topmost textbox in the Visualizer form).

And the answer:

... The reason the string visualizers can display the original expression is that they are built into Visual Studio at a lower level than the Visualizers interface we provide. They are written in native code and work when debugging native code, while the visualizers architecture we provide is limited to managed code.

Sorry! Let me know if you have any more questions.

Scott Nonnenberg Program Manager Visual C# Team

This was on http://blogs.msdn.com/scottno/default.aspx but I think Scott is no longer a Microsoft employee and the posting won't be available online...