RogerB's MessageBoxEx from CODEPROJECT; an include-only extension for MessageBox, supporting a timeout timer

MessageBoxEx.cs

/*
* From author RogerB: https://www.codeproject.com/script/membership/view.aspx?mid=716667
* Code source article: https://www.codeproject.com/articles/7968/messagebox-with-a-timeout-for-net
* Licensing: https://www.codeproject.com/info/cpol10.aspx
*/

using System;
using System.Text;
using System.Runtime.InteropServices;
using System.Security.Permissions;

[assembly: SecurityPermission(SecurityAction.RequestMinimum, UnmanagedCode = true)]

namespace System.Windows.Forms
{
	public class MessageBoxEx
	{
		public static DialogResult Show(string text, uint uTimeout)
		{
			Setup("", uTimeout);
			return MessageBox.Show(text);
		}
		
		public static DialogResult Show(string text, string caption, uint uTimeout)
		{
			Setup(caption, uTimeout);
			return MessageBox.Show(text, caption);
		}
		
		public static DialogResult Show(string text, string caption, MessageBoxButtons buttons, uint uTimeout)
		{
			Setup(caption, uTimeout);
			return MessageBox.Show(text, caption, buttons);
		}
		
		public static DialogResult Show(string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, uint uTimeout)
		{
			Setup(caption, uTimeout);
			return MessageBox.Show(text, caption, buttons, icon);
		}
		
		public static DialogResult Show(string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton, uint uTimeout)
		{
			Setup(caption, uTimeout);
			return MessageBox.Show(text, caption, buttons, icon, defButton);
		}
		
		public static DialogResult Show(string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton, MessageBoxOptions options, uint uTimeout)
		{
			Setup(caption, uTimeout);
			return MessageBox.Show(text, caption, buttons, icon, defButton, options);
		}
		
		public static DialogResult Show(IWin32Window owner, string text, uint uTimeout)
		{
			Setup("", uTimeout);
			return MessageBox.Show(owner, text);
		}
		
		public static DialogResult Show(IWin32Window owner, string text, string caption, uint uTimeout)
		{
			Setup(caption, uTimeout);
			return MessageBox.Show(owner, text, caption);
		}
		
		public static DialogResult Show(IWin32Window owner, string text, string caption, MessageBoxButtons buttons, uint uTimeout)
		{
			Setup(caption, uTimeout);
			return MessageBox.Show(owner, text, caption, buttons);
		}
		
		public static DialogResult Show(IWin32Window owner, string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, uint uTimeout)
		{
			Setup(caption, uTimeout);
			return MessageBox.Show(owner, text, caption, buttons, icon);
		}
		
		public static DialogResult Show(IWin32Window owner, string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton, uint uTimeout)
		{
			Setup(caption, uTimeout);
			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, uint uTimeout)
		{
			Setup(caption, uTimeout);
			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 const int WM_DESTROY = 0x0002;
		public const int WM_INITDIALOG = 0x0110;
		public const int WM_TIMER = 0x0113;
		public const int WM_USER = 0x400;
		public const int DM_GETDEFID = WM_USER + 0;

		[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;
		};

		private const int TimerID = 42;
		private static HookProc hookProc;
		private static TimerProc hookTimer;
		private static uint hookTimeout;
		private static string hookCaption;
		private static IntPtr hHook;
		
		static MessageBoxEx()
		{
			hookProc = new HookProc(MessageBoxHookProc);
			hookTimer = new TimerProc(MessageBoxTimerProc);
			hookTimeout = 0;
			hookCaption = null;
			hHook = IntPtr.Zero;
		}
		
		private static void Setup(string caption, uint uTimeout)
		{
			if (hHook != IntPtr.Zero)
				throw new NotSupportedException("multiple calls are not supported");
			
			hookTimeout = uTimeout;
			hookCaption = caption != null ? caption : "";
			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 (hookCaption != null && msg.message == WM_INITDIALOG)
			{
				int nLength = GetWindowTextLength(msg.hwnd);
				StringBuilder text = new StringBuilder(nLength + 1);

				GetWindowText(msg.hwnd, text, text.Capacity);

				if (hookCaption == text.ToString())
				{
					hookCaption = null;
					SetTimer(msg.hwnd, (UIntPtr)TimerID, hookTimeout, hookTimer);
					UnhookWindowsHookEx(hHook);
					hHook = IntPtr.Zero;
				}
			}

			return CallNextHookEx(hook, nCode, wParam, lParam);
		}

		private static void MessageBoxTimerProc(IntPtr hWnd, uint uMsg, UIntPtr nIDEvent, uint dwTime)
		{
			if (nIDEvent == (UIntPtr)TimerID)
			{
				short dw = (short)SendMessage(hWnd, DM_GETDEFID, IntPtr.Zero, IntPtr.Zero);
			
				EndDialog(hWnd, (IntPtr)dw);
			}
		}
	}
}