Center MessageBox C#

A

alex_f_il

The class centers MessageBox inside the parent rectangle.
Enjoy!

using System;
using System.Windows.Forms;
using System.Text;
using System.Drawing;
using System.Runtime.InteropServices;

namespace Utils {
public class MessageBoxEx {
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);
}
}
}
 

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