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Test and Debug a Visualizer

Important

Starting with Visual Studio 2022 version 17.9, visualizers can now be written in .NET 6.0+ that run out-of-process using the new VisualStudio.Extensibility model. For extensions created using the new model, see the documentation at Create Visual Studio debugger visualizers instead. If you need to support older versions of Visual Studio or want to ship your custom visualizers as part of a library DLL, then use the information in this article, which applies only to the older model of extension development (VSSDK).

Once you write a visualizer, debug and test it.

One way to test a visualizer is by installing it in Visual Studio and calling it from a debugger window. (See How to: Install a Visualizer.) If you do that, then use a second instance of Visual Studio to attach and debug the visualizer, which is running in the first instance of the debugger.

An easier way to debug a visualizer is to run the visualizer from a test driver. The visualizer APIs make it easy to create such a driver, which is called the visualizer development host.

Note

Currently, the test driver is supported only when calling the visualizer from a .NET Framework application.

To create a visualizer development host

  1. In your debugger-side class, include a static method that creates a VisualizerDevelopmentHost object and calls its show method:

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

    The parameters used to construct the host are the data object that will be shown in the visualizer (objectToVisualize) and the type of the debugger side class.

  2. To call TestShowVisualizer, add the following statement. If you created your visualizer in a class library, you need to create an executable to call the class library and place this statement in your executable:

    DebuggerSide.TestShowVisualizer(myString);

    For a more complete example, see Walkthrough: Writing a Visualizer in C#.

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