Question

I know the title is bit confusing for my question.

Let me explain:-
There are some DLLs written by my seniors and I use them in C# as follows:

Say, Existing DLL name is SeniorDLL and I want to use function SeniorFunc from that DLL.
What I do is:-

private delegate int SeniorFunc(IntPtr Blah);

[DllImport("kernel32")]
public extern static IntPtr LoadLibrary(string lpFileName);

[DllImport("kernel32", CharSet = CharSet.Ansi)]
public extern static IntPtr GetProcAddress(IntPtr hModule, string lpProcName);

SeniorFunc fp_Senior;

and in function where I want to use this function, Before first function call I write:

IntPtr handle;

    handle = IntPtr.Zero;
    handle = LoadLibrary("<DLL Path>");

    IntPtr fPtr = GetProcAddress(handle, "SeniorFunc");
    fp_Senior = (SeniorFunc)Marshal.GetDelegateForFunctionPointer(fPtr, typeof(SeniorFunc));

and then I use this function via fp_Senior(<Parameter>);

Now I want to create such DLL for me in C# by which I’ll be able to call functions from DLL.
Currently I created a DLL but I have create an instance of class in DLL and then have to access like ClassInstance.MyFunction(<Parameters>);

How can I get directly function calls without creating an instance?
In other words, (I don’t know I am correct or wrong) How can I create APIs??

Thanks!!

Answer 1

There is no such a thing as a method outside a class in C#. So if you must call a method, you have to specify the class name.

The difference with the DLLs you are currently using is that those DLLs are written in C/C++ or other non-.NET language which does not enforce a strict object-oriented approach like C# does.

Thus, nothing forces you to create an instance of a class when calling a method from a .NET library. If a method is declared as static, you can call it directly through ClassName.MethodName().