Sample Mdbg extension

Here is a template for playing around with an extension for the MDbg sample (Mdbg is the managed debuggeer written in C#). It adds an "Addition" command to MDbg that adds two numbers. Not very exciting, but it shows the plumbing.  You can download the MDbg sample here.  I'll likely update this if I think of a better sample command than just "addition".

These extensions target the MDbg sample, and not Mdbg in the SDK.

Please note that the MDbg sample is just a sample. We don't consider it a real production debugger (use VS2005 for that). The main goal for extensions is to let hobbyists play around with prototyping debugging ideas and exploring our APIs.

// Template for an MDbg extension
// You can build this in Visual Studio 2005 by adding a new Class Library project
// to the Mdbg sample, and then adding the proper references.
// More about Mdbg here:
// This must have a reference to the other Mdbg dlls (corapi, corapi2, mdbgeng, mdbgext)
// Assuming this is caled "myfile.cs", compile like:
// csc /t:library /debug+ myfile.cs /r:corapi.dll /r:corapi2.dll /r:mdbgeng.dll /r:mdbgext.dll
// You must then load this extension into Mdbg via the "load" command before
// you can use the commands in this extension. For example, at an Mdbg prompt, type:
// load C:\fullpath\subdir\MyFile.dll

using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;

using Microsoft.Samples.Tools.Mdbg;
using Microsoft.Samples.Debugging.MdbgEngine;
using Microsoft.Samples.Debugging.CorDebug;
using System.Globalization;

// extension class name must have [MDbgExtensionEntryPointClass] attribute on it
// and implement a LoadExtension()
Url =
"", // put your URL here
ShortDescription = "Eventing test extension." // your "help" description for group of commands
public class MyMdbgExt : CommandBase
// This is called when the extension is first loaded.
// Extensions are loaded via MDbg's "Load" command.
public static void LoadExtension()
// Add all the commands from this class
MDbgAttributeDefinedCommand.AddCommandsFromType(Shell.Commands, typeof(MyMdbgExt));

// You can do other initialization here, or write out to the MDbg console.
// Use WriteOutput instead of "Console.WriteLine", because the Mdbg console may be redirected
// (to a GUI or logfile, etc).
WriteOutput("My mdbg Extension loaded");

// Commands are identified by the "CommandDescription" attribute on a method.
CommandName =
"addition", // name of your command in the shell.

// How many characters does the shell need to match? This can be used
// as a "shortcut" to your command
MinimumAbbrev = 3,

// Short help string that appears next to this command in the "Help" list.
ShortHelp = "adds two numbers",

// Longer help string for when we explicitly ask about this command.
// It can include sample usage.
LongHelp = @"Adds two numbers.
add 2 4 // returns 6
public static void MyCommand(string argString)
// This is a trivial command to add two numbers.
// For more complex commands, see mdbgCommands.cs in the Mdbg project.
ArgParser args = new ArgParser(argString);
if (args.Count != 2)
throw new MDbgShellException("Expected 2 arguments");
int a = args.AsInt(0); // throws if not int
int b = args.AsInt(1);
String.Format(CultureInfo.InvariantCulture, "Adding {0} + {1} = {2}", a, b, a+b));

} // end class for my extensions.


Comments (4)

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    re: Sample Mdbg extension

  2. Jan Stranik is on MSDN TV talking about MDbg, the managed-debugging sample written in C#.  See the…

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