问题
The extension I am writing started life from the Walkthrough: Creating a Margin Glyph example provided by Microsoft: https://msdn.microsoft.com/en-us/library/ee361745.aspx
Everything works fine, except I am trying to trigger the redrawing or updating of the margin glyphs whenever the data I use for deciding which line to draw a glyph on changes.
Basically I have a button in a tool window, when the user clicks the button, I want a glyph to appear in the margin. Right now, it does not appear until you scroll away and back, or obviously close and reload the document.
I have researched this, and have seen some code samples that use IViewTaggerProvider instead of ITaggerProvider. In those cases it appeared that a handler for a LayoutChanged event is able to be added to the ITagger derived class which also contains the GetTags method. However I was unable to successfully switch the code from using ITaggerProvider to IViewTaggerProvider, the extension crashed when run. I don't know if this is a change that will lead to the solution, or if it's unnecessary.
How can I force the glyph to get rendered? Can I raise an event of some kind to force the GetTags code to be exercised? How would I raise that event from outside of the class? From the tool window for example?
回答1:
You were on the right path, changing from ITaggerProvider to IViewTaggerProvider allowed me to redraw the glyphs. I used the Implementing a Brace Matching Tagger Provider section in Walkthrough: Displaying Matching Braces example to make these changes.
Using the IViewTaggerProvider, you can then call
TagsChanged?.Invoke(this, new SnapshotSpanEventArgs(
new SnapshotSpan(
SourceBuffer.CurrentSnapshot,
0,
SourceBuffer.CurrentSnapshot.Length)));
in your functions to explicitly call GetTags and go over the spans in the current snapshot.
来源：https://stackoverflow.com/questions/36760891/visual-studio-mef-extension-force-margin-glyphs-to-be-updated-or-redraw