Question

I need to show a modeless dialog in .NET 1.1. The following code works in .NET 2.0 or higher:

[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
private static extern IntPtr GetActiveWindow();

private void ShowModelessOwnedDialog()
{
   IntPtr wHnd = GetActiveWindow();
   NativeWindow parent = NativeWindow.FromHandle(wHnd);
   MyForm f = new MyForm();
   f.Show(parent);
}

The call Show(IWin32Window) was introduced in .NET 2.0. Do you know how to trick this code to work in .NET 1.1? Maybe any unmanaged call?

Answer 1

This is the way to assign an owner to a managed form in .NET 1.1. I extracted the following code from @Dave Markle answer and the Show(IWin32Window) implemantation of .NET 2.0.

    private void AssignOwner()
    {
        AssignOwner(this, GetActiveWindow());
    }

    private void AssignOwner(Form f, IntPtr ownerHandle)
    {
        if (ownerHandle == IntPtr.Zero) return;

        NativeWindow parent = NativeWindow.FromHandle(ownerHandle);

        GetWindowLong(new HandleRef(f, f.Handle), -8);
        SetWindowLong(new HandleRef(f, f.Handle), -8, new HandleRef(parent, ownerHandle));
    }

    public static IntPtr GetWindowLong(HandleRef hWnd, int nIndex)
    {
        if (IntPtr.Size == 4)
        {
            return GetWindowLong32(hWnd, nIndex);
        }
        return GetWindowLongPtr64(hWnd, nIndex);
    }

    public static IntPtr SetWindowLong(HandleRef hWnd, int nIndex, HandleRef dwNewLong)
    {
        if (IntPtr.Size == 4)
        {
            return SetWindowLongPtr32(hWnd, nIndex, dwNewLong);
        }
        return SetWindowLongPtr64(hWnd, nIndex, dwNewLong);
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
    private static extern IntPtr GetActiveWindow();
    [DllImport("user32.dll", EntryPoint = "GetWindowLong", CharSet = CharSet.Auto)]
    public static extern IntPtr GetWindowLong32(HandleRef hWnd, int nIndex);
    [DllImport("user32.dll", EntryPoint = "GetWindowLongPtr", CharSet = CharSet.Auto)]
    public static extern IntPtr GetWindowLongPtr64(HandleRef hWnd, int nIndex);
    [DllImport("user32.dll", EntryPoint = "SetWindowLong", CharSet = CharSet.Auto)]
    public static extern IntPtr SetWindowLongPtr32(HandleRef hWnd, int nIndex, HandleRef dwNewLong);
    [DllImport("user32.dll", EntryPoint = "SetWindowLongPtr", CharSet = CharSet.Auto)]
    public static extern IntPtr SetWindowLongPtr64(HandleRef hWnd, int nIndex, HandleRef dwNewLong);