How to export all methods in an unmanaged dll to managed c#?

I have a c++ dll with 10 methods and 12 properties, is there any way or any application to export the p/invoke format of the methods to be used in c# ? I have use OLE Viewer to inspect all the methods, for example :

[id(0x00000013)]
BSTR GetCPUID(
short BeginAddress,
short EndAddress);

but i dont know how to use this function in c#.

Probably this article may help you

http://www.codeproject.com/Articles/18032/How-to-Marshal-a-C-Class

Let me know if this helps.