c# - Dynamically generate code for DllImport depending on application version -

i write .net-extension can loaded different versions of unmanaged application.

below imported some_func_v01, some_func_v02, , some_func_v03 functions:

[dllimport("some_library_v1.0.dll", callingconvention = callingconvention.cdecl,      charset = charset.unicode, entrypoint = "func_name")] extern static private void some_func_v01(string msg);  [dllimport("some_library_v2.0.dll", callingconvention = callingconvention.cdecl,      charset = charset.unicode, entrypoint = "func_name")] extern static private void some_func_v02(string msg);  [dllimport("some_library_v3.0.dll", callingconvention = callingconvention.cdecl,      charset = charset.unicode, entrypoint = "func_name")] extern static private void some_func_v03(string msg);  ...  public void some_func(string msg)  {   switch (application.version.major)   {     case 1: some_func_v01(msg); break;     case 2: some_func_v02(msg); break;     case 3: some_func_v03(msg); break;   } } 

the some_library library part of target application , has same version application.

the problem edit code of extension when new versions of application appear. dynamically generate code depending of application version. example, application version 1:

[dllimport("some_library_v1.0.dll", callingconvention = callingconvention.cdecl,      charset = charset.unicode, entrypoint = "func_name")] extern static private void some_func(string msg); 

i can through powershell hosting using, maybe more simple way exists... wouldn't want create powershell hosting carry out task.

is exist simple way it?

i think best solution load dlls dynamically.

use winapi loadlibrary , getprocaddress address of function. use marshal.getdelegateforfunctionpointer .net delegate.

example:

//skipping winapi native definitions //you need define delegate type: [unmanagedfunctionpointer(callingconvention.stdcall, charset = charset.unicode, setlasterror = true)] delegate void myfunctype(string msg);   //how delegate object:  var library = loadlibrary(librarynamechosenatruntime); var funcptr = getprocaddress(library, funcname); var func = marshal.getdelegateforfunctionpointer<myfunctype>(funcptr);  // can use func delegate // can store delegate object somewhere , reuse. func("msg");