moel@176: /*
moel@176:
moel@176: Version: MPL 1.1/GPL 2.0/LGPL 2.1
moel@176:
moel@176: The contents of this file are subject to the Mozilla Public License Version
moel@176: 1.1 (the "License"); you may not use this file except in compliance with
moel@176: the License. You may obtain a copy of the License at
moel@176:
moel@176: http://www.mozilla.org/MPL/
moel@176:
moel@176: Software distributed under the License is distributed on an "AS IS" basis,
moel@176: WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
moel@176: for the specific language governing rights and limitations under the License.
moel@176:
moel@176: The Original Code is the Open Hardware Monitor code.
moel@176:
moel@176: The Initial Developer of the Original Code is
moel@176: Michael Möller <m.moeller@gmx.ch>.
moel@176: Portions created by the Initial Developer are Copyright (C) 2010
moel@176: the Initial Developer. All Rights Reserved.
moel@176:
moel@176: Contributor(s):
moel@176:
moel@176: Alternatively, the contents of this file may be used under the terms of
moel@176: either the GNU General Public License Version 2 or later (the "GPL"), or
moel@176: the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
moel@176: in which case the provisions of the GPL or the LGPL are applicable instead
moel@176: of those above. If you wish to allow use of your version of this file only
moel@176: under the terms of either the GPL or the LGPL, and not to allow others to
moel@176: use your version of this file under the terms of the MPL, indicate your
moel@176: decision by deleting the provisions above and replace them with the notice
moel@176: and other provisions required by the GPL or the LGPL. If you do not delete
moel@176: the provisions above, a recipient may use your version of this file under
moel@176: the terms of any one of the MPL, the GPL or the LGPL.
moel@176:
moel@176: */
moel@176:
moel@176: using System;
moel@176: using System.Runtime.InteropServices;
moel@176: using System.Windows.Forms;
moel@176:
moel@176: namespace OpenHardwareMonitor.GUI {
moel@176: public class ShowDesktop {
moel@176: private static ShowDesktop instance = new ShowDesktop();
moel@176:
moel@176: public delegate void ShowDesktopChangedEventHandler(bool showDesktop);
moel@176:
moel@176: private event ShowDesktopChangedEventHandler ShowDesktopChangedEvent;
moel@176:
moel@176: private System.Threading.Timer timer;
moel@176: private bool showDesktop = false;
moel@176: private NativeWindow referenceWindow;
moel@176: private string referenceWindowCaption =
moel@176: "OpenHardwareMonitorShowDesktopReferenceWindow";
moel@176:
moel@176: private ShowDesktop() {
moel@176: // create a reference window to detect show desktop
moel@176: referenceWindow = new NativeWindow();
moel@176: CreateParams cp = new CreateParams();
moel@176: cp.ExStyle = GadgetWindow.WS_EX_TOOLWINDOW;
moel@176: cp.Caption = referenceWindowCaption;
moel@176: referenceWindow.CreateHandle(cp);
moel@176: NativeMethods.SetWindowPos(referenceWindow.Handle,
moel@176: GadgetWindow.HWND_BOTTOM, 0, 0, 0, 0, GadgetWindow.SWP_NOMOVE |
moel@176: GadgetWindow.SWP_NOSIZE | GadgetWindow.SWP_NOACTIVATE |
moel@176: GadgetWindow.SWP_NOSENDCHANGING);
moel@176:
moel@176: // start a repeated timer to detect "Show Desktop" events
moel@176: timer = new System.Threading.Timer(OnTimer, null,
moel@176: System.Threading.Timeout.Infinite, System.Threading.Timeout.Infinite);
moel@176: }
moel@176:
moel@176: private void StartTimer() {
moel@176: timer.Change(0, 200);
moel@176: }
moel@176:
moel@176: private void StopTimer() {
moel@176: timer.Change(System.Threading.Timeout.Infinite,
moel@176: System.Threading.Timeout.Infinite);
moel@176: }
moel@176:
moel@176: // the desktop worker window (if available) can hide the reference window
moel@176: private IntPtr GetDesktopWorkerWindow() {
moel@176: IntPtr shellWindow = NativeMethods.GetShellWindow();
moel@176: if (shellWindow == IntPtr.Zero)
moel@176: return IntPtr.Zero;
moel@176:
moel@176: int shellId;
moel@176: NativeMethods.GetWindowThreadProcessId(shellWindow, out shellId);
moel@176:
moel@176: IntPtr workerWindow = IntPtr.Zero;
moel@176: while ((workerWindow = NativeMethods.FindWindowEx(
moel@176: IntPtr.Zero, workerWindow, "WorkerW", null)) != IntPtr.Zero) {
moel@176:
moel@176: int workerId;
moel@176: NativeMethods.GetWindowThreadProcessId(workerWindow, out workerId);
moel@176: if (workerId == shellId) {
moel@176: IntPtr window = NativeMethods.FindWindowEx(
moel@176: workerWindow, IntPtr.Zero, "SHELLDLL_DefView", null);
moel@176: if (window != IntPtr.Zero) {
moel@176: IntPtr desktopWindow = NativeMethods.FindWindowEx(
moel@176: window, IntPtr.Zero, "SysListView32", null);
moel@176: if (desktopWindow != IntPtr.Zero)
moel@176: return workerWindow;
moel@176: }
moel@176: }
moel@176: }
moel@176: return IntPtr.Zero;
moel@176: }
moel@176:
moel@176: private void OnTimer(Object state) {
moel@176: bool showDesktopDetected;
moel@176:
moel@176: IntPtr workerWindow = GetDesktopWorkerWindow();
moel@176: if (workerWindow != IntPtr.Zero) {
moel@176: // search if the reference window is behind the worker window
moel@176: IntPtr reference = NativeMethods.FindWindowEx(
moel@176: IntPtr.Zero, workerWindow, null, referenceWindowCaption);
moel@179: showDesktopDetected = reference != IntPtr.Zero;
moel@176: } else {
moel@176: // if there is no worker window, then nothing can hide the reference
moel@176: showDesktopDetected = false;
moel@176: }
moel@176:
moel@176: if (showDesktop != showDesktopDetected) {
moel@176: showDesktop = showDesktopDetected;
moel@176: if (ShowDesktopChangedEvent != null) {
moel@176: ShowDesktopChangedEvent(showDesktop);
moel@176: }
moel@176: }
moel@176: }
moel@176:
moel@176: public static ShowDesktop Instance {
moel@176: get { return instance; }
moel@176: }
moel@176:
moel@176: // notify when the "show desktop" mode is changed
moel@176: public event ShowDesktopChangedEventHandler ShowDesktopChanged {
moel@176: add {
moel@176: // start the monitor timer when someone is listening
moel@176: if (ShowDesktopChangedEvent == null)
moel@176: StartTimer();
moel@176: ShowDesktopChangedEvent += value;
moel@176: }
moel@176: remove {
moel@176: ShowDesktopChangedEvent -= value;
moel@176: // stop the monitor timer if nobody is interested
moel@176: if (ShowDesktopChangedEvent == null)
moel@176: StopTimer();
moel@176: }
moel@176: }
moel@176:
moel@176: private static class NativeMethods {
moel@176: private const string USER = "user32.dll";
moel@176:
moel@176: [DllImport(USER, CallingConvention = CallingConvention.Winapi)]
moel@176: public static extern bool SetWindowPos(IntPtr hWnd,
moel@176: IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags);
moel@176:
moel@176: [DllImport(USER, CallingConvention = CallingConvention.Winapi)]
moel@176: public static extern IntPtr FindWindowEx(IntPtr hwndParent,
moel@176: IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
moel@176:
moel@176: [DllImport(USER, CallingConvention = CallingConvention.Winapi)]
moel@176: public static extern IntPtr GetShellWindow();
moel@176:
moel@176: [DllImport(USER, CallingConvention = CallingConvention.Winapi)]
moel@176: public static extern int GetWindowThreadProcessId(IntPtr hWnd,
moel@176: out int processId);
moel@176: }
moel@176: }
moel@176: }