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c#reflectionlate-binding

Release Late-Bound Object in C#

Is there a way to release an object that was accessed using late-binding (i.e. created by the Activator.CreateInstance() method)?

I have an application that transforms files from one format to another. The assemblies that perform these translations live in a folder in my application directory.

When the application first starts up, I can delete these assemblies from the translation folder without any errors. However, once I process a document through the application (and have bound to one of the translation assemblies using late-binding), I can no longer delete the translation assemblies. At this point, I'm receiving an error message stating that the file is "in use by another application".

Is there a way to "release" the late-bound object in my application once I'm finished using it?

Solution

  • Once an assembly is loaded into an application domain it'll remain until the app domain shuts down.

    To get around this load the assembly into it's own application domain, for example:

    AppDomain app = AppDomain.CreateDomain("PlugInDomain");
ObjectHandle objectHandle = app.CreateInstanceFrom(assemblyPath, 
             "MyNamespace.MyComponent");
MyComponent component = (MyComponent) objectHandle.Unwrap();

// do stuff

// Now kill app domain, assembly can be overwritten after this.
AppDomain.Unload(app);