Get Rid of EXE/DLL Locks by using ShadowCopyFiles Appropriately

Introduction

Unfortunately, the .NET Framework does not support modifications on the existing AppDomains. Therefore a wrapper is necessary in case someone wants to configure AppDomain settings for an executable. This article gives a brief overview how such a wrapper might look like.

Background

With the release of .NET Framework 2.0, Microsoft introduced a new philosophy regarding the configuration of created AppDomains. The idea is that existing AppDomain configurations must not be altered anymore. Thus, if you use methods that affect the configuration (e.g. ShadowCopyFiles) of an existing AppDomain, Visual Studio shows a warning, informing that this method is marked obsolete.

So far so good, problems occur in case you want to change the configuration of the default AppDomain of an application. One might expect support from the app.config file. Unfortunately, the framework does not contain such settings yet.
That's where the wrapper described in this article comes in.

Using the Code

The wrapper class is a very small, independent console application. It hosts a custom AppDomain in which the configured application is executed with the given settings.

using System;
using System.Configuration;

namespace SmartSoft.ExecutableWrapper
{
    internal class ExecutableWrapper
    {
        private static void Main(string[] commandLineArguments)
        {
            AppDomainSetup executableDomainSetup;
            AppDomain executableDomain;

            // Create app domain setup
            executableDomainSetup = new AppDomainSetup();
            // Apply settings
            executableDomainSetup.ShadowCopyFiles = 
                ConfigurationManager.AppSettings["ShadowCopyFiles"];
            // Create new app domain
            executableDomain = AppDomain.CreateDomain
                ("", AppDomain.CurrentDomain.Evidence, executableDomainSetup);
            // Execute configured application in the newly created app domain
            executableDomain.ExecuteAssembly(ConfigurationManager.AppSettings
                ["ApplicationFullPath"], AppDomain.CurrentDomain.Evidence, 
                commandLineArguments);
        }
    }
}

The App.config file contains the following appSettings:

<appSettings>
    <add key="ShadowCopyFiles" value="true"/>
    <add key="ApplicationFullPath" value="C:\AnyPath\MyExecutable.exe"/>
</appSettings>

Points of Interest

As you might have recognized, command line arguments are directly passed through to the executed application. In some cases, this needs to be changed.

The example above covers only the ShadowCopyFiles property of the AppDomainSetup. However, this approach can be expanded with any property or method being part of the AppDomainSetup.

History

• 22^nd December, 2007 - Initial post