Get the current filename from a Visual Studio text adornment extension

Question

I'm new to VS extension development. I'm currently working with the text adornment sample in VS 2015 and have been able to get coloured boxes showing correctly. Now I want to extend the sample so the adornment only appears on certain file names.

Googling has said I can use ITextDocumentFactoryService.TryGetTextDocument interface with the IWpfTextView.TextBuffer property to get a filename. This sounds great. But I can't seem to actually get the interface.

In my class I have:

    [Import]
    public ITextDocumentFactoryService TextDocumentFactoryService = null;

But it is always NULL.

How can I get ITextDocumentFactoryService?

namespace Test
{
    internal sealed class TestAdornment
    {
        [Import]
        public ITextDocumentFactoryService TextDocumentFactoryService = null;

        public TestAdornment(IWpfTextView view)
        {
        }

        /// <summary>
        /// Adds the scarlet box behind the 'a' characters within the given line
        /// </summary>
        /// <param name="line">Line to add the adornments</param>
        private void CreateVisuals(ITextViewLine line)
        {
            // TextDocumentFactoryService is NULL
        }
    }
}

Hudak

Answer 1

TextAdornmentTextViewCreationListener.cs

[Export(typeof(IWpfTextViewCreationListener))]
[ContentType("text")]
[TextViewRole(PredefinedTextViewRoles.Document)]
internal sealed class TextAdornmentTextViewCreationListener : IWpfTextViewCreationListener
{
    [Import]
    public ITextDocumentFactoryService textDocumentFactory { get; set; }

    //...

    public void TextViewCreated(IWpfTextView textView)
    {
        new TextAdornment(textView, textDocumentFactory);
    }
}

TextAdornment.cs

internal sealed class TextAdornment
    {
        private readonly ITextDocumentFactoryService textDocumentFactory;
        private ITextDocument TextDocument;

        //...    

        public TextAdornment(IWpfTextView view, ITextDocumentFactoryService textDocumentFactory)
        {
            //...

            this.textDocumentFactory = textDocumentFactory;

            //...
        }

     internal void OnLayoutChanged(object sender, TextViewLayoutChangedEventArgs e)
        {
            var res = this.textDocumentFactory.TryGetTextDocument(this.view.TextBuffer, out this.TextDocument);
            if (res)
            {
                //this.TextDocument.FilePath;
            }
            else
            {
                //ERROR
            }
        }
    }

Aldis

You should add some explanation. – Karlee

Thanks! It worked for me. Is there any way to get path, relative to the project root (solution)? – Sukiyaki

Answer 2

You got it via dependency injection.

As you only submitted 2 lines of code I suppose your context is set up, either explicitly by you, either implicitly by some environment who calls your code.

• You should declare property instead of field
• It should be public

Then automagically big brother will set it for you before you first access to it.

...or...

You can use constructor injection instead. Note: It is not you who will create your class.

private readonly ITextDocumentFactoryService _textDocumentFactoryService;

[ImportingConstructor]
internal YourClass(ITextDocumentFactoryService textDocumentFactoryService)
{
    _textDocumentFactoryService = textDocumentFactoryService;
}

Solatium

It looks like it is declared properly but it doesn't get set. My member call (CreateVisuals) states that it is null. Therefore my context must not be set up right. – Hudak

Answer 3

So in my case I needed to put the import statement into the AdornmentTextViewCreationListener. This implements IWpfTextViewCreationListener and is the one with the following decorating the class.

[Export(typeof(IWpfTextViewCreationListener))]
[ContentType("text")]
[TextViewRole(PredefinedTextViewRoles.Document)]

Then I can add

private readonly ITextDocumentFactoryService _textDocumentFactoryService;
[ImportingConstructor]

to my class

Hudak