private static IntPtr MessageBoxHookProc(Int32 nCode, IntPtr wParam, IntPtr lParam)
{
if (nCode < 0)
{
return(CenteredDialogBox.CallNextHookEx(windowHook, nCode, wParam, lParam));
}
CWPRETSTRUCT msg = (CWPRETSTRUCT)Marshal.PtrToStructure(lParam, typeof(CWPRETSTRUCT));
IntPtr hook = windowHook;
if (msg.Message == (Int32)CbtHookAction.HCBT_ACTIVATE)
{
try
{
CenteredDialogBox.CenterWindow(msg.Hwnd);
}
finally
{
CenteredDialogBox.UnhookWindowsHookEx(windowHook);
windowHook = IntPtr.Zero;
}
}
return(CenteredDialogBox.CallNextHookEx(hook, nCode, wParam, lParam));
}
private static void CenterWindow(IntPtr childWindowHandle)
{
Rectangle recChild = new Rectangle(0, 0, 0, 0);
Boolean success = GetWindowRect(childWindowHandle, ref recChild);
Int32 width = recChild.Width - recChild.X;
Int32 height = recChild.Height - recChild.Y;
Rectangle parentRectangle = new Rectangle(0, 0, 0, 0);
success = CenteredDialogBox.GetWindowRect(ownerPtr, ref parentRectangle);
System.Drawing.Point centerPoint = new System.Drawing.Point(0, 0);
centerPoint.X = parentRectangle.X + ((parentRectangle.Width - parentRectangle.X) / 2);
centerPoint.Y = parentRectangle.Y + ((parentRectangle.Height - parentRectangle.Y) / 2);
System.Drawing.Point startPoint = new System.Drawing.Point(0, 0);
startPoint.X = centerPoint.X - (width / 2);
startPoint.Y = centerPoint.Y - (height / 2);
startPoint.X = (startPoint.X < 0) ? 0 : startPoint.X;
startPoint.Y = (startPoint.Y < 0) ? 0 : startPoint.Y;
Int32 result = CenteredDialogBox.MoveWindow(childWindowHandle, startPoint.X, startPoint.Y, width, height, false);
}
private static void Initialize()
{
if (windowHook != IntPtr.Zero)
{
throw new NotSupportedException("Multiple calls are not supported.");
}
if (ownerPtr != null)
{
ProcessThread processThread = Process.GetCurrentProcess().Threads
.OfType <ProcessThread>()
.FirstOrDefault(thread => thread.ThreadState == ThreadState.Running);
if (processThread != null)
{
windowHook = CenteredDialogBox.SetWindowsHookEx(WH_CALLWNDPROCRET, hookProc, IntPtr.Zero, processThread.Id);
}
}
}
/// <summary>
/// Shows a dialog box with the specified parameters.
/// </summary>
/// <param name="owner">The creator of this messagebox, on which we will center this.</param>
/// <param name="text">The body text.</param>
/// <param name="caption">The window caption.</param>
/// <param name="buttons">The buttons choices to display</param>
/// <param name="icon">The icon to display.</param>
/// <returns>The result based on the button pressed.</returns>
public static MessageBoxResult Show(Window owner, String text, String caption, MessageBoxButton buttons, MessageBoxImage icon)
{
ownerPtr = new WindowInteropHelper(owner).Handle;
CenteredDialogBox.Initialize();
return(MessageBox.Show(owner, text, caption, buttons, icon));
}
