Creating a Visual Studio debug visualizer

Note: This post was written a while back but sat in draft. I’ve published this now, but I’m not sure it’s relevant to the latest versions etc. so please bear this in mind.

A Visualizer is a feature where, if you run an app. and whilst debugging you put the mouse over a variable a little debugger popup appears. You have a drop down to display the value in the variable as XML, HTML etc.

  1. Create class lib project
  2. Add references to Microsoft.VisualStudio.DebuggerVisualizers.dll and System.Windows.Forms
using Microsoft.VisualStudio.DebuggerVisualizers;
using System.Windows.Forms;

[
    assembly: System.Diagnostics.DebuggerVisualizer(
        typeof(MyFirstVisualizer.DebuggerSide),
        typeof(VisualizerObjectSource),
        Target = typeof(System.String),
        Description = "My First Visualizer")
]
namespace MyFirstVisualizer
{
    public class DebuggerSide : DialogDebuggerVisualizer
    {
        protected override void Show(IDialogVisualizerService windowService, IVisualizerObjectProvider objectProvider)
        {
            MessageBox.Show(objectProvider.GetObject().ToString());
        }

        public static void TestShowVisualizer(object objectToVisualize)
        {
            var visualizerHost = new VisualizerDevelopmentHost(objectToVisualize, typeof(DebuggerSide));
            visualizerHost.ShowVisualizer();
        }
    }
}

TestShowVisualizer allows us to test from a console app

  1. Create console app
  2. Add reference to Microsoft.VisualStudio.DebuggerVisualizers.dll and our project reference
class TestConsole
{
   static void Main(string[] args)
   {
      var myString = "Hello, World";
      DebuggerSide.TestShowVisualizer(myString);
   }
}

To install, copy to 

{visual studio deployment folder};\Common7\Packages\Debugger\Visualizers

i.e. C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\Packages\Debugger\Visualizers

and

MyDocuments\Visual Studio 2015\Visualizers