I summarized some best practice rules in writing a COM-visible assembly according to my recent work.
1. In AssemblyInfo.cs, I wrote two attributes:
They indicated I didn't want all public classes to be COM-visible and I didn't want Visual Studio to implicitly generate a random GUID as my library ID.
2. I unchecked the "Register for COM interop" box in the project's Build option because I didn't want Visual Studio to register the assembly on the build machine.
3. I wrote each COM-visible class like the following example:
public class MyClass
Here I explicitly declared the class as COM-visible and gave it a GUID as the class ID. Visual Studio would generate a random GUID if I didn't specify one. I used ClassInterfaceType.None to prevent Visual Studio from generating an interface for the class automatically. The automatic behavior would expose methods which I didn't want to expose and could introduce unwanted method declarations.
4. I declared an interface for each COM-visible class explicitly like the following example:
public interface IMyClass
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