VSIX how to get current snapshot document name? - visual-studio-2017

Question

I have been trying to to create an extension that highlights specific line numbers for me in Visual Studio in the margins.
I manged to get my marking in the margins using predefined line number but for it to work properly I need to know what the current document FullName is (Path and filename)
After much googling I figured out how to do it with the sample code (which is not ideal)
DTE2 dte = (DTE2)System.Runtime.InteropServices.Marshal.GetActiveObject("VisualStudio.DTE.15.0");
var activeDocument = dte.ActiveDocument;
var docName = activeDocument.Name;
var docFullName = activeDocument.FullName;
Now I know the problems here
is that is for specific version bases on the text
there is no way to select which instance (when running more than one VS)
It seems to be very slow
I have a feeling I should be doing this with MEF Attributes but the MS docs examples are so simple that they do not work for me. I scanned a few SO questions too and I just cannot get them to work. They mostly talk about Services.. which I do not have and have no idea how to get.
The rest of my code uses SnapshotSpans as in the example Extension of Todo_Classification examples which is great if you do NOT need to know the file name.
I have never done any extensions development. Please can somebody help me do this correctly.

Answer 1

You can use following code to get a file from a snapshot without any dependencies.
public string GetDocumentPath(Microsoft.VisualStudio.Text.ITextSnapshot ts)
{
Microsoft.VisualStudio.Text.ITextDocument textDoc;
bool rc = ts.TextBuffer.Properties.TryGetProperty(
typeof(Microsoft.VisualStudio.Text.ITextDocument), out textDoc);
if (rc && textDoc != null)
return textDoc.FilePath;
return null;
}
If you don't mind adding Microsoft.CodeAnalysis.EditorFeatures.Text to your project it will provide you with an extension method Document GetOpenDocumentInCurrentContextWithChanges() on the Microsoft.VisualStudio.Text.Snapshot class. (Plus many other Rosyln based helpers)
using Microsoft.CodeAnalysis.Text;
Document doc = span.Snapshot.GetOpenDocumentInCurrentContextWithChanges();