C#

[DllImport("user32.dll")]
private extern static IntPtr SetActiveWindow(IntPtr handle);
private const int WM_ACTIVATE = 6;
private const int WA_INACTIVE = 0;


protected override void WndProc(ref Message m)
{
    if (m.Msg == WM_ACTIVATE)
    {
        if (((int)m.WParam & 0xFFFF) != WA_INACTIVE)
        {
            if (m.LParam != IntPtr.Zero)
            {
                SetActiveWindow(m.LParam);
            }
            else
            {
                SetActiveWindow(IntPtr.Zero);
            }
        }
    }

    base.WndProc(ref m);
}

  [DllImport("user32", CharSet = CharSet.Auto)]<br />
        private extern static int SendMessage(<br />
           IntPtr handle, int msg, int wParam, IntPtr lParam);<br />
<br />
        [DllImport("user32", CharSet = CharSet.Auto)]<br />
        private extern static int PostMessage(<br />
            IntPtr handle, int msg, int wParam, IntPtr lParam);<br />
<br />
        private const int WM_ACTIVATE = 0x006;<br />
        private const int WM_ACTIVATEAPP = 0x01C;<br />
        private const int WM_NCACTIVATE = 0x086;<br />
<br />
<br />
        /// <summary><br />
        /// Subclasses the owning form's existing Window Procedure to enables the <br />
        /// title bar to remain active when a popup is show, and to detect if<br />
        /// the user clicks onto another application whilst the popup is visible.<br />
        /// </summary><br />
        /// <param name="m">Window Procedure Message</param><br />
        protected override void WndProc(ref Message m)<br />
        {<br />
            <br />
                // check for WM_ACTIVATEAPP and WM_NCACTIVATE<br />
                if (m.Msg == WM_NCACTIVATE)<br />
                {<br />
                    <br />
                    // Check if the title bar will made inactive:<br />
                    if (((int)m.WParam) == 0)<br />
                    {<br />
                        xyz += m.Msg + " ";<br />
                        // If so reactivate it.<br />
                        SendMessage(this.Handle, WM_NCACTIVATE, 1, IntPtr.Zero);<br />
<br />
                        // Note it's no good to try and consume this message;<br />
                        // if you try to do that you'll end up with windows<br />
                        // that don't respond.<br />
                    }<br />
<br />
                }<br />
                else if (m.Msg == WM_ACTIVATEAPP)<br />
                {<br />
                   <br />
                    // Check if the application is being deactivated.<br />
                    if ((int)m.WParam == 0)<br />
                    {<br />
                        xyz += m.Msg + " ";<br />
                        // And put the title bar into the inactive state:<br />
                        PostMessage(this.Handle, WM_NCACTIVATE, 0, IntPtr.Zero);<br />
                    }<br />
                }<br />
                <br />
                base.WndProc(ref m);<br />
        } 

Zeokat wrote:

I´m using System.Configuration but only could read/write into the default section named <appsettings>...