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c#.netapplicationdomain

Common uses and best practices for application domains in .NET?

What are some guidelines and best practices for when to create new application domains within an application?

Also, what are some common uses and examples of how multiple application domains are used whithin an application?

Solution

  • The most common scenario I've seen is to be able to provide extensibility with a different security model than the main program.

    Loading a plugin in a separate AppDomain allows two things:

    1. You can implement a more restricted security model
    2. You can prevent the plugin from tearing down your application if it's buggy

    Another nice use of AppDomains are to load and inspect an assembly. Doing this in a separate AppDomain allows you to glean information (or run code) from a separate assembly, then unload the entire assembly from your process's space. If you load the assembly directly, there is no way to unload it. This is also useful if you want to be able to, at runtime, "upgrade" a type to a new version (ie: load a remote assembly, and reload it later).