In. Net, the Winform program displays MessageBox. Show in the middle of the parent form.

Source: Internet
Author: User

The following statement is displayed in the middle of the screen by default.

DialogResult dr = MessageBox. Show ("Do you want to delete this data? "," Confirm deletion ", MessageBoxButtons. OKCancel, MessageBoxIcon. Information, MessageBoxDefaultButton. Button2); if (dr = DialogResult. Cancel) {return ;}

To display MessageBoxEx. Show in the middle of the parent form, you need to re-write the following class and call the WINAPI function.

using System;using System.Windows.Forms;using System.Text;using System.Drawing;using System.Runtime.InteropServices;public class MessageBoxEx{    private static IWin32Window _owner;    private static HookProc _hookProc;    private static IntPtr _hHook;    public static DialogResult Show(string text)    {        Initialize();        return MessageBox.Show(text);    }    public static DialogResult Show(string text, string caption)    {        Initialize();        return MessageBox.Show(text, caption);    }    public static DialogResult Show(string text, string caption, MessageBoxButtons buttons)    {        Initialize();        return MessageBox.Show(text, caption, buttons);    }    public static DialogResult Show(string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon)    {        Initialize();        return MessageBox.Show(text, caption, buttons, icon);    }    public static DialogResult Show(string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton)    {        Initialize();        return MessageBox.Show(text, caption, buttons, icon, defButton);    }    public static DialogResult Show(string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton, MessageBoxOptions options)    {        Initialize();        return MessageBox.Show(text, caption, buttons, icon, defButton, options);    }    public static DialogResult Show(IWin32Window owner, string text)    {        _owner = owner;        Initialize();        return MessageBox.Show(owner, text);    }    public static DialogResult Show(IWin32Window owner, string text, string caption)    {        _owner = owner;        Initialize();        return MessageBox.Show(owner, text, caption);    }    public static DialogResult Show(IWin32Window owner, string text, string caption, MessageBoxButtons buttons)    {        _owner = owner;        Initialize();        return MessageBox.Show(owner, text, caption, buttons);    }    public static DialogResult Show(IWin32Window owner, string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon)    {        _owner = owner;        Initialize();        return MessageBox.Show(owner, text, caption, buttons, icon);    }    public static DialogResult Show(IWin32Window owner, string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton)    {        _owner = owner;        Initialize();        return MessageBox.Show(owner, text, caption, buttons, icon, defButton);    }    public static DialogResult Show(IWin32Window owner, string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton, MessageBoxOptions options)    {        _owner = owner;        Initialize();        return MessageBox.Show(owner, text, caption, buttons, icon,                               defButton, 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.Handle, ref recParent);        Point ptCenter = new Point(0, 0);        ptCenter.X = recParent.X + ((recParent.Width - recParent.X) / 2);        ptCenter.Y = recParent.Y + ((recParent.Height - recParent.Y) / 2);        Point ptStart = new 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);    }}
Call Method
DialogResult dr = MessageBoxEx. Show (this, "Do you want to delete this data? "," Confirm deletion ", MessageBoxButtons. OKCancel, MessageBoxIcon. Information, MessageBoxDefaultButton. Button2); if (dr = DialogResult. Cancel) {return ;}



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