code for hiding the taskbar

USB Lockdown/taskbarController.cs

+/*
+ *	Copyright (c) 2008..11 by Simon Baer
+ * 
+ *  You may use this code for whatever you want.
+ */
+
+using System;
+using System.Text;
+using System.Runtime.InteropServices;
+using System.Diagnostics;
+
+namespace USB_Lockdown
+{
+	/// <summary>
+	/// Helper class for hiding/showing the taskbar and startmenu on
+	/// Windows XP and Vista.
+	/// </summary>
+	public static class Taskbar
+	{
+		[DllImport("user32.dll")]
+		private static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int count); 
+		[DllImport("user32.dll", CharSet = CharSet.Auto)]
+		private static extern bool EnumThreadWindows(int threadId, EnumThreadProc pfnEnum, IntPtr lParam);
+		[DllImport("user32.dll", SetLastError = true)]
+		private static extern System.IntPtr FindWindow(string lpClassName, string lpWindowName);
+		[DllImport("user32.dll", SetLastError = true)]
+		private static extern IntPtr FindWindowEx(IntPtr parentHandle, IntPtr childAfter, string className,  string windowTitle);
+        [DllImport("user32.dll")]
+        private static extern IntPtr FindWindowEx(IntPtr parentHwnd, IntPtr childAfterHwnd, IntPtr className, string windowText);
+        [DllImport("user32.dll")]
+		private static extern int ShowWindow(IntPtr hwnd, int nCmdShow);
+		[DllImport("user32.dll")]
+		private static extern uint GetWindowThreadProcessId(IntPtr hwnd, out int lpdwProcessId);
+
+		private const int SW_HIDE = 0;
+		private const int SW_SHOW = 5;
+
+		private const string VistaStartMenuCaption = "Start";
+		private static IntPtr vistaStartMenuWnd = IntPtr.Zero;
+		private delegate bool EnumThreadProc(IntPtr hwnd, IntPtr lParam);
+
+		/// <summary>
+		/// Show the taskbar.
+		/// </summary>
+		public static void Show()
+		{
+			SetVisibility(true);
+		}
+
+		/// <summary>
+		/// Hide the taskbar.
+		/// </summary>
+		public static void Hide()
+		{
+			SetVisibility(false);
+		}
+
+		/// <summary>
+		/// Sets the visibility of the taskbar.
+		/// </summary>
+		public static bool Visible
+		{
+			set { SetVisibility(value); }
+		}
+
+		/// <summary>
+		/// Hide or show the Windows taskbar and startmenu.
+		/// </summary>
+		/// <param name="show">true to show, false to hide</param>
+		private static void SetVisibility(bool show)
+		{
+			// get taskbar window
+			IntPtr taskBarWnd = FindWindow("Shell_TrayWnd", null);
+
+			// try it the WinXP way first...
+			IntPtr startWnd = FindWindowEx(taskBarWnd, IntPtr.Zero, "Button", "Start");
+
+            if (startWnd == IntPtr.Zero)
+            {
+                // try an alternate way, as mentioned on CodeProject by Earl Waylon Flinn
+                startWnd = FindWindowEx(IntPtr.Zero, IntPtr.Zero, (IntPtr)0xC017, "Start");
+            }
+
+			if (startWnd == IntPtr.Zero)
+			{
+				// ok, let's try the Vista easy way...
+				startWnd = FindWindow("Button", null);
+
+				if (startWnd == IntPtr.Zero)
+				{
+					// no chance, we need to to it the hard way...
+					startWnd = GetVistaStartMenuWnd(taskBarWnd);
+				}
+			}
+			
+			ShowWindow(taskBarWnd, show ? SW_SHOW : SW_HIDE);
+			ShowWindow(startWnd, show ? SW_SHOW : SW_HIDE);
+		}
+
+		/// <summary>
+		/// Returns the window handle of the Vista start menu orb.
+		/// </summary>
+		/// <param name="taskBarWnd">windo handle of taskbar</param>
+		/// <returns>window handle of start menu</returns>
+		private static IntPtr GetVistaStartMenuWnd(IntPtr taskBarWnd)
+		{
+			// get process that owns the taskbar window
+			int procId;
+			GetWindowThreadProcessId(taskBarWnd, out procId);
+
+			Process p = Process.GetProcessById(procId);
+			if (p != null)
+			{
+				// enumerate all threads of that process...
+				foreach (ProcessThread t in p.Threads)
+				{
+					EnumThreadWindows(t.Id, MyEnumThreadWindowsProc, IntPtr.Zero);
+				}
+			}
+			return vistaStartMenuWnd;
+		}
+
+		/// <summary>
+		/// Callback method that is called from 'EnumThreadWindows' in 'GetVistaStartMenuWnd'.
+		/// </summary>
+		/// <param name="hWnd">window handle</param>
+		/// <param name="lParam">parameter</param>
+		/// <returns>true to continue enumeration, false to stop it</returns>
+		private static bool MyEnumThreadWindowsProc(IntPtr hWnd, IntPtr lParam)
+		{
+			StringBuilder buffer = new StringBuilder(256);
+			if (GetWindowText(hWnd, buffer, buffer.Capacity) > 0)
+			{
+				Console.WriteLine(buffer);
+				if (buffer.ToString() == VistaStartMenuCaption)
+				{
+					vistaStartMenuWnd = hWnd;
+					return false;
+				}
+			}
+			return true;
+		}
+	}
+}