Code Analysis CA1060 Fix

You have detailed information about this warning here: http://msdn.microsoft.com/en-us/library/ms182161.aspx. In short:

For most applications, moving P/Invokes to a new class that is named NativeMethods is enough.

Try moving them all into a NativeMethod class, it will solve the problem

Your code should look like this after fixing it

public class NativeMethods {
[DllImport("user32.dll")]
private static extern int GetWindowLong(IntPtr hwnd, int index);

[DllImport("user32.dll")]
private static extern int SetWindowLong(IntPtr hwnd, int index, int newStyle);

[DllImport("user32.dll")]
private static extern bool SetWindowPos(IntPtr hwnd, IntPtr hwndInsertAfter,
               int x, int y, int width, int height, uint flags);

[DllImport("user32.dll")]
private static extern IntPtr SendMessage(IntPtr hwnd, uint msg,
               IntPtr wParam, IntPtr lParam);
}

Remember to change all the places where you are calling these methods

Before change

SendMessage(IntPtr hwnd, uint msg,IntPtr wParam, IntPtr lParam)

should be

NativeMethods.SendMessage(IntPtr hwnd, uint msg,IntPtr wParam, IntPtr lParam)