How to call win32 dll in windows 7

Question

From within a C# application(Visual Studio 2008) i am calling a win32 dll using DllImport. Everything works fine in Windows XP. However when i use the same exe and dll in Windows 7, the win32 dll fails to get loaded. Do i need to write any extra code to invoke a win32 dll from Windows 7 ?

Answer 1

Before building the C# program, make sure that in Visual studio Configuration Manager you choose "x86" and not "any CPU" as the platform. If any CPU is selected, your C# application runs as a 64bit process in Windows 7 and tries to load the 32-bit win32 dll in to the 64-bit process which would fail as explained here and here .

Answer 2

Is your windows 7 64 bit?

Is you .NET exe marked as AnyCPU?

If the answer is yes to the above then you need to mark you .exe as x86 via the Configuration manager in Visual Studio.