C#'s scroll bar adornments?

Question

When writing a Visual Studio extension, is there any way to influence how it renders map-mode scroll bar for c#?

Answer 1

I don't have time for the full answer, but I will write the short one because there is next to zero info about it on the net:

1. Create VSIX solution.
2. Add Item and in the "Extensibility" category choose "Editor margin"

3. In the "[yourEditorMarginName]Factory.cs" file that was created alonside the margin file after you did step 2 set the following lines:

       [MarginContainer(PredefinedMarginNames.VerticalScrollBar)]
       [Order(Before = PredefinedMarginNames.LineNumber)]
   

4. Go back to the "[yourEditorMarginName].cs" file. Make sure that you remove the following lines in the constructor:

       this.Height = 20;
       this.ClipToBounds = true;
       this.Width = 200;
   

5. Now you received a reference to IWpfTextView inside the constructor, sign up to its OnLayoutChanged event (or use some other event that suits you):

       TextView.LayoutChanged += OnLayoutChanged;
   

6. In the OnLayoutChanged, you can do the following to add a rectangle adornment:

       var rect = new Rectangle();
       double bottom;
       double firstLineTop;
       MapLineToPixels([someLineYouNeedToHighlight], out firstLineTop, out bottom);
       SetTop(rect, firstLineTop);
       SetLeft(rect, 0);
       rect.Height = bottom - firstLineTop;
       rect.Width = [yourWidth];
       Color color = [your Color];
       rect.Fill = new SolidColorBrush(color);
   
       Children.Add(rect);
   

7. And here is MapLineToPixels():

       private void MapLineToPixels(ITextSnapshotLine line, out double top, out double bottom)
       {
       double mapTop = ScrollBar.Map.GetCoordinateAtBufferPosition(line.Start) - 0.5;
       double mapBottom = ScrollBar.Map.GetCoordinateAtBufferPosition(line.End) + 0.5;
       top = Math.Round(ScrollBar.GetYCoordinateOfScrollMapPosition(mapTop)) - 2.0;
       bottom = Math.Round(ScrollBar.GetYCoordinateOfScrollMapPosition(mapBottom)) + 2.0;
       }
   

8. Yeah the ScrollBar variable is something you can get this way:

   public ScrollbarMargin(IWpfTextView textView, IWpfTextViewMargin marginContainer/*, MarginCore marginCore*/)
   {
       ITextViewMargin scrollBarMargin = marginContainer.GetTextViewMargin(PredefinedMarginNames.VerticalScrollBar);
       ScrollBar = (IVerticalScrollBar)scrollBarMargin;