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Expression Tree Visualizer Sample

.NET Framework 3.5

The Expression Tree Visualizer sample is a working implementation of a visualizer that can be run inside the Visual Studio debugger to view the contents of an expression tree.

To get samples and instructions for installing them

  • Do one or more of the following:

    • On the Help menu, click Samples.

      The Readme displays information about samples.

    • Visit the Visual Studio 2008 Samples Web site. The most recent versions of samples are available there.

    • Locate samples on the computer on which Visual Studio is installed. By default, samples and a Readme file are installed in drive:\Program Files\Microsoft Visual Studio 9.0\Samples\lcid. For Express editions of Visual Studio, all samples are located online.

For more information, see Visual Studio Samples.


The Expression Tree Visualizer can be used in a debug environment to visualize expressions. To use the visualizer, the dll that is generated by the ExpressionTreeVisualizer project must be copied to ...\Documents\Visual Studio 2008\Visualizers. You may have to create the Visualizers directory. In Windows XP and earlier versions, use the My Documents directory rather than Documents. If you have permissions, you can also copy the file to the following directory: ...\Program Files\Microsoft Visual Studio 9.0\Common7\Packages\Debugger\Visualizers.

Security noteSecurity Note:

This sample code is intended to illustrate a concept, and it shows only the code that is relevant to that concept. It may not meet the security requirements for a specific environment, and it should not be used exactly as shown. We recommend that you add security and error-handling code to make your projects more secure and robust. Microsoft provides this sample code "AS IS" with no warranties.

To run this sample

  • Press F5.

    To use the Visualizer, copy the .dll that is generated by the ExpressionTreeVisualizer project to the following location:

    • On Windows XP: My Documents\Visual Studio 2008\Visualizers

    • On Windows Vista: Documents\Visual Studio 2008\Visualizers

The Expression Tree Visualizer can be used in a debug environment to visualize expressions.

This console program provides the ability to host the visualizer outside Visual Studio without having to copy the DLL.

The visualizer window sometimes becomes hidden if you run this program in console mode. Try by using the GuiHost instead of the ExpressionTreeVisualizerApplication.


Many LINQ samples require XML files and/or the version of the Northwind sample database that is located in the Data sample. If you install the Data Sample in the same parent folder as the other LINQ samples, the path for the XML files and database file will be resolved automatically. Many sample files also require the Object Dumper Sample project.