Question

I am trying to implement Windows Messaging in C# in order to communicate a HTML page with a regular exe. What I need to do is to create a new window with a specific class name and window name, so that other processes can send Windows Messages to my Activex application.

[DllImport("user32.dll", SetLastError = true)]
        static extern IntPtr CreateWindowEx(
           WindowStylesEx dwExStyle,
           string lpClassName,
           string lpWindowName,
           WindowStyles dwStyle,
           int x,
           int y,
           int nWidth,
           int nHeight,
           IntPtr hWndParent,
           IntPtr hMenu,
           IntPtr hInstance,
           IntPtr lpParam);


            IntPtr temp = CreateWindowEx(0, "privateclassname", "privatewindowname",
                WindowStyles.WS_CHILD | WindowStyles.WS_VISIBLE, 0, 0, 1, 1,
                IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero);

This is what I’ ve been trying but temp always get 0 instead of a proper window handle. What is wrong with this piece of code? I suspect hWndParent parameter. A give it 0 because I don’ t know the parent’ s handle, or it even exists. Thanks in advance

Answer 1

You are passing in WS_CHILD for a window style flag, but you are not passing a parent window handle (you are passing 0/NULL). Try removing the WS_CHILD style.

Also, see my comment about calling RegisterClass above (if that applies).