This question should not be answered until it is clarified. What type of DLL? There are many types of DLLs. There are native DLLs and there are DLL files that have a type library (COM object or something like that) and there are .Net Class Libraries. If you need to make a native DLL or a COM object type of DLL then you cannot do that using C#. If you need to make a Class Library type of DLL then you should say Class Library instead of DLL.
Of course I understand that you might not know that it is a Class Library and that is why you are asking. So it is my opinion that when someone says DLL file, the specifics about what kind of DLL is important.
So what type of DLL do you need?
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