C#: Marshalling a “pointer to an int array” from a SendMessage() lParam

Question

I\'m trying to subclass an unmanaged statusbar window from my managed COM server using a class inherited from NativeWindow, and am running into a wall trying to make sense of ho

Answer 1

Following the "dtb"'s comment, you can borrow some code from this SO entry.

The LPARAM you must supply is a pointer to the first element of the array. Then all you have to do is:

int[] parts = new int[]{ 1, 2, 3, 4 };
int nParts = parts.Length;
IntPtr pointer = Marshal.AllocHGlobal(nParts * Marshal.SizeOf(typeof(int)));
for (int i = 0; i < nParts; i++) {
    Marshal.WriteInt32(pointer, i * Marshal.SizeOf(typeof(int), parts[i]));
}
// Call SendMessage with WPARAM = nParts and LPARAM = Pointer
Marshal.FreeHGlobal(pointer);