You can do this using COM interop if your own executable is capable of using COM objects. If you register the .NET assembly for interaction, then your own executable can use your .NET classes as "regular" COM objects, and when the first one is created, it will deploy the CLR inside its own process. Similary, if you can expose COM objects from your own executable, then you can use them from your .NET code if you create an interop assembly (or even without a type library if you use only IDispatch).
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