Debugging OnStart Method in .NET Service when Debbuger.Launch Doesn't Work

Introduction

A lot of workarounds exist to debug the OnStart method of a service. A straight way with Debugger.Launch() is described in How to Debug a Windows Service. But what if this wouldn't work, e.g. on Windows Vista x64? This sample shows a simple method to attach the debugger to the service process and debug the OnStart method.

How It Works

The service process should wait till you have attached the debugger. The service process should not timeout. Just look at the code, it's quite easy.

Using the Code

All you have to do, is to copy this code snippet in your Onstart method of your service class (derived from ServiceBase).

Using Directives

using System.Diagnostics;  // a quite useful namespace for debugging issues
using System.Threading;

OnStart Method

protected override void OnStart(string[] args)
{
#if DEBUG
    while (!Debugger.IsAttached)      // Waiting until debugger is attached
    {
        RequestAdditionalTime(1000);  // Prevents the service from timeout
        Thread.Sleep(1000);           // Gives you time to attach the debugger   
    }
    RequestAdditionalTime(20000);     // for Debugging the OnStart method,
                                      // increase as needed to prevent timeouts
#endif
    
    // here is your startup code with breakpoints
} 

Start the service as usual. The service will wait until you attach the debugger to the service process. You can set breakpoints in your start code and debug it.

History

• 12^th September, 2007: Initial version tested on Vista x64 / VS2005 with a x64 compiled C# project