How to get MessageBox.Show() to pop up in the middle of my WPF application?

Question

I have a 700w x 300h WPF applciation and can drag it anywhere on my large screen.

When my application executes:

MessageBox.Show("Sorry, this function is not yet implemented."); 

the mesage box appears in the middle of my screen, which may or may not even be near the application itself.

How can I get my MessageBox to appear in the middle of my application instead?

Answer 1

Here's a version of the MessageBoxEx helper class posted in the other thread that uses WPF style message boxes (Note that you still need to reference System.Drawing):

using System; using System.Text; using System.Runtime.InteropServices; using System.Windows; using System.Windows.Interop; using System.Drawing;  public class MessageBoxEx {     private static IntPtr _owner;     private static HookProc _hookProc;     private static IntPtr _hHook;      public static MessageBoxResult Show(string text)     {         Initialize();         return MessageBox.Show(text);     }      public static MessageBoxResult Show(string text, string caption)     {         Initialize();         return MessageBox.Show(text, caption);     }      public static MessageBoxResult Show(string text, string caption, MessageBoxButton buttons)     {         Initialize();         return MessageBox.Show(text, caption, buttons);     }      public static MessageBoxResult Show(string text, string caption, MessageBoxButton buttons, MessageBoxImage icon)     {         Initialize();         return MessageBox.Show(text, caption, buttons, icon);     }      public static MessageBoxResult Show(string text, string caption, MessageBoxButton buttons, MessageBoxImage icon, MessageBoxResult defResult)     {         Initialize();         return MessageBox.Show(text, caption, buttons, icon, defResult);     }      public static MessageBoxResult Show(string text, string caption, MessageBoxButton buttons, MessageBoxImage icon, MessageBoxResult defResult, MessageBoxOptions options)     {         Initialize();                     return MessageBox.Show(text, caption, buttons, icon, defResult, options);     }      public static MessageBoxResult Show(Window owner, string text)     {         _owner = new WindowInteropHelper(owner).Handle;         Initialize();         return MessageBox.Show(owner, text);     }      public static MessageBoxResult Show(Window owner, string text, string caption)     {         _owner = new WindowInteropHelper(owner).Handle;         Initialize();         return MessageBox.Show(owner, text, caption);     }      public static MessageBoxResult Show(Window owner, string text, string caption, MessageBoxButton buttons)     {         _owner = new WindowInteropHelper(owner).Handle;         Initialize();         return MessageBox.Show(owner, text, caption, buttons);     }      public static MessageBoxResult Show(Window owner, string text, string caption, MessageBoxButton buttons, MessageBoxImage icon)     {         _owner = new WindowInteropHelper(owner).Handle;         Initialize();         return MessageBox.Show(owner, text, caption, buttons, icon);     }      public static MessageBoxResult Show(Window owner, string text, string caption, MessageBoxButton buttons, MessageBoxImage icon, MessageBoxResult defResult)     {         _owner = new WindowInteropHelper(owner).Handle;         Initialize();         return MessageBox.Show(owner, text, caption, buttons, icon, defResult);     }      public static MessageBoxResult Show(Window owner, string text, string caption, MessageBoxButton buttons, MessageBoxImage icon, MessageBoxResult defResult, MessageBoxOptions options)     {         _owner = new WindowInteropHelper(owner).Handle;         Initialize();         return MessageBox.Show(owner, text, caption, buttons, icon,                                 defResult, options);     }      public delegate IntPtr HookProc(int nCode, IntPtr wParam, IntPtr lParam);      public delegate void TimerProc(IntPtr hWnd, uint uMsg, UIntPtr nIDEvent, uint dwTime);      public const int WH_CALLWNDPROCRET = 12;      public enum CbtHookAction : int     {         HCBT_MOVESIZE = 0,         HCBT_MINMAX = 1,         HCBT_QS = 2,         HCBT_CREATEWND = 3,         HCBT_DESTROYWND = 4,         HCBT_ACTIVATE = 5,         HCBT_CLICKSKIPPED = 6,         HCBT_KEYSKIPPED = 7,         HCBT_SYSCOMMAND = 8,         HCBT_SETFOCUS = 9     }      [DllImport("user32.dll")]     private static extern bool GetWindowRect(IntPtr hWnd, ref Rectangle lpRect);      [DllImport("user32.dll")]     private static extern int MoveWindow(IntPtr hWnd, int X, int Y, int nWidth, int nHeight, bool bRepaint);      [DllImport("User32.dll")]     public static extern UIntPtr SetTimer(IntPtr hWnd, UIntPtr nIDEvent, uint uElapse, TimerProc lpTimerFunc);      [DllImport("User32.dll")]     public static extern IntPtr SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, IntPtr lParam);      [DllImport("user32.dll")]     public static extern IntPtr SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);      [DllImport("user32.dll")]     public static extern int UnhookWindowsHookEx(IntPtr idHook);      [DllImport("user32.dll")]     public static extern IntPtr CallNextHookEx(IntPtr idHook, int nCode, IntPtr wParam, IntPtr lParam);      [DllImport("user32.dll")]     public static extern int GetWindowTextLength(IntPtr hWnd);      [DllImport("user32.dll")]     public static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int maxLength);      [DllImport("user32.dll")]     public static extern int EndDialog(IntPtr hDlg, IntPtr nResult);      [StructLayout(LayoutKind.Sequential)]     public struct CWPRETSTRUCT     {         public IntPtr lResult;         public IntPtr lParam;         public IntPtr wParam;         public uint message;         public IntPtr hwnd;     } ;      static MessageBoxEx()     {         _hookProc = new HookProc(MessageBoxHookProc);         _hHook = IntPtr.Zero;     }      private static void Initialize()     {         if (_hHook != IntPtr.Zero)         {             throw new NotSupportedException("multiple calls are not supported");         }          if (_owner != null)         {             _hHook = SetWindowsHookEx(WH_CALLWNDPROCRET, _hookProc, IntPtr.Zero, AppDomain.GetCurrentThreadId());         }     }      private static IntPtr MessageBoxHookProc(int nCode, IntPtr wParam, IntPtr lParam)     {         if (nCode < 0)         {             return CallNextHookEx(_hHook, nCode, wParam, lParam);         }          CWPRETSTRUCT msg = (CWPRETSTRUCT)Marshal.PtrToStructure(lParam, typeof(CWPRETSTRUCT));         IntPtr hook = _hHook;          if (msg.message == (int)CbtHookAction.HCBT_ACTIVATE)         {             try             {                 CenterWindow(msg.hwnd);             }             finally             {                 UnhookWindowsHookEx(_hHook);                 _hHook = IntPtr.Zero;             }         }          return CallNextHookEx(hook, nCode, wParam, lParam);     }      private static void CenterWindow(IntPtr hChildWnd)     {         Rectangle recChild = new Rectangle(0, 0, 0, 0);         bool success = GetWindowRect(hChildWnd, ref recChild);          int width = recChild.Width - recChild.X;         int height = recChild.Height - recChild.Y;          Rectangle recParent = new Rectangle(0, 0, 0, 0);         success = GetWindowRect(_owner, ref recParent);          System.Drawing.Point ptCenter = new System.Drawing.Point(0, 0);         ptCenter.X = recParent.X + ((recParent.Width - recParent.X) / 2);         ptCenter.Y = recParent.Y + ((recParent.Height - recParent.Y) / 2);           System.Drawing.Point ptStart = new System.Drawing.Point(0, 0);         ptStart.X = (ptCenter.X - (width / 2));         ptStart.Y = (ptCenter.Y - (height / 2));          ptStart.X = (ptStart.X < 0) ? 0 : ptStart.X;         ptStart.Y = (ptStart.Y < 0) ? 0 : ptStart.Y;          int result = MoveWindow(hChildWnd, ptStart.X, ptStart.Y, width,                                 height, false);     } } 

Answer 2

This was answered here for Windows.Forms but with the following added to your class, you can get it to work in WPF.

You have to add a reference to System.Windows.Forms & System.Drawing for the class above to work and to do the following.

public partial class YourWPFWindow : Window, System.Windows.Forms.IWin32Window {     public IntPtr Handle     {         get { return new WindowInteropHelper(this).Handle; }     } } 

Then you can call MessageBoxEx with:

MessageBoxEx.Show(this, "Message"); 

It should show up in the middle of your window.