我們曾經想過能夠在我們的計算機上將窗口隱蔽起來，不想被從身邊走過的老板看見。嘗試便捷的Windows隱藏并定義熱鍵來控制它們。下面我們將演示如何通過熱鍵，我們將會用到DllImports of Win32 API、CallBacks/Delegates，定制事件與事件的句柄。

using System;
using System.Text;
using System.Collections;
using System.Runtime.InteropServices;

namespace WindowHider
{
    /// <summary>
    /// Object used to control a Windows Form.
    /// </summary>
    public class Window
    {
        /// <summary>
        /// Win32 API Imports
        /// </summary>
        [DllImport("user32.dll")] private static extern  
            bool ShowWindowAsync(IntPtr hWnd, int nCmdShow);
        [DllImport("user32.dll")] private static extern  
            bool SetForegroundWindow(IntPtr hWnd);
        [DllImport("user32.dll")] private static extern  
            bool IsIconic(IntPtr hWnd);
        [DllImport("user32.dll")] private static extern  
            bool IsZoomed(IntPtr hWnd);
        [DllImport("user32.dll")] private static extern  
            IntPtr GetForegroundWindow();
        [DllImport("user32.dll")] private static extern  
            IntPtr GetWindowThreadProcessId(IntPtr hWnd, IntPtr ProcessId);
        [DllImport("user32.dll")] private static extern  
            IntPtr AttachThreadInput(IntPtr idAttach, IntPtr idAttachTo, int fAttach);

        /// <summary>
        /// Win32 API Constants for ShowWindowAsync()
        /// </summary>
        private const int SW_HIDE = 0;
        private const int SW_SHOWNORMAL = 1;
        private const int SW_SHOWMINIMIZED = 2;
        private const int SW_SHOWMAXIMIZED = 3;
        private const int SW_SHOWNOACTIVATE = 4;
        private const int SW_RESTORE = 9;
        private const int SW_SHOWDEFAULT = 10;

        /// <summary>
        /// Private Fields
        /// </summary>
        private IntPtr m_hWnd;
        private string m_Title;
        private bool m_Visible = true;
        private string m_Process;
        private bool m_WasMax = false;

        /// <summary>
        /// Window Object's Public Properties
        /// </summary>
        public IntPtr hWnd
        {
            get{return m_hWnd;}
        }
        public string Title
        {
            get{return m_Title;}
        }
        public string Process
        {
            get{return m_Process;}
        }

        /// <summary>
        /// Sets this Window Object's visibility
        /// </summary>
        public bool Visible
        {
            get{return m_Visible;}
            set
            {
                //show the window
                if(value == true)
                {
                    if(m_WasMax)
                    {
                        if(ShowWindowAsync(m_hWnd,SW_SHOWMAXIMIZED))
                            m_Visible = true;
                    }
                    else
                    {
                        if(ShowWindowAsync(m_hWnd,SW_SHOWNORMAL))
                            m_Visible = true;
                    }
                }
                //hide the window
                if(value == false)
                {
                    m_WasMax = IsZoomed(m_hWnd);
                    if(ShowWindowAsync(m_hWnd,SW_HIDE))
                        m_Visible = false;
                }
            }
        }

        /// <summary>
        /// Constructs a Window Object
        /// </summary>
        /// <param name="Title">Title Caption</param>
        /// <param name="hWnd">Handle</param>
        /// <param name="Process">Owning Process</param>
        public Window(string Title, IntPtr hWnd, string Process)
        {
            m_Title = Title;
            m_hWnd = hWnd;
            m_Process = Process;
        }

        //Override ToString()  
        public override string ToString()
        {
            //return the title if it has one, if not return the process name
            if (m_Title.Length > 0)
            {
                return m_Title;
            }
            else
            {
                return m_Process;
            }
        }

        /// <summary>
        /// Sets focus to this Window Object
        /// </summary>
        public void Activate()
        {
            if(m_hWnd == GetForegroundWindow())
                return;

            IntPtr ThreadID1 = GetWindowThreadProcessId(GetForegroundWindow(),
                                                        IntPtr.Zero);
            IntPtr ThreadID2 = GetWindowThreadProcessId(m_hWnd,IntPtr.Zero);
             
            if (ThreadID1 != ThreadID2)
            {
                AttachThreadInput(ThreadID1,ThreadID2,1);
                SetForegroundWindow(m_hWnd);
                AttachThreadInput(ThreadID1,ThreadID2,0);
            }
            else
            {
                SetForegroundWindow(m_hWnd);
            }

            if (IsIconic(m_hWnd))
            {
                ShowWindowAsync(m_hWnd,SW_RESTORE);
            }
            else
            {
                ShowWindowAsync(m_hWnd,SW_SHOWNORMAL);
            }
        }
    }

    /// <summary>
    /// Collection used to enumerate Window Objects
    /// </summary>
    public class Windows : IEnumerable, IEnumerator
    {
        /// <summary>
        /// Win32 API Imports
        /// </summary>
        [DllImport("user32.dll")] private static extern  
              int GetWindowText(int hWnd, StringBuilder title, int size);
        [DllImport("user32.dll")] private static extern  
              int GetWindowModuleFileName(int hWnd, StringBuilder title, int size);
        [DllImport("user32.dll")] private static extern  
              int EnumWindows(EnumWindowsProc ewp, int lParam);  
        [DllImport("user32.dll")] private static extern  
              bool IsWindowVisible(int hWnd);

        //delegate used for EnumWindows() callback function
        public delegate bool EnumWindowsProc(int hWnd, int lParam);

        private int m_Position = -1; // holds current index of wndArray,  
                                     // necessary for IEnumerable
         
        ArrayList wndArray = new ArrayList(); //array of windows
         
        //Object's private fields
        private bool m_invisible = false;
        private bool m_notitle = false;

        /// <summary>
        /// Collection Constructor with additional options
        /// </summary>
        /// <param name="Invisible">Include invisible Windows</param>
        /// <param name="Untitled">Include untitled Windows</param>
        public Windows(bool Invisible, bool Untitled)
        {
            m_invisible = Invisible;
            m_notitle = Untitled;

            //Declare a callback delegate for EnumWindows() API call
            EnumWindowsProc ewp = new EnumWindowsProc(EvalWindow);
            //Enumerate all Windows
            EnumWindows(ewp, 0);
        }
        /// <summary>
        /// Collection Constructor
        /// </summary>
        public Windows()
        {
            //Declare a callback delegate for EnumWindows() API call
            EnumWindowsProc ewp = new EnumWindowsProc(EvalWindow);
            //Enumerate all Windows
            EnumWindows(ewp, 0);
        }
        //EnumWindows CALLBACK function
        private bool EvalWindow(int hWnd, int lParam)
        {
            if (m_invisible == false && !IsWindowVisible(hWnd))
                return(true);

            StringBuilder title = new StringBuilder(256);
            StringBuilder module = new StringBuilder(256);

            GetWindowModuleFileName(hWnd, module, 256);
            GetWindowText(hWnd, title, 256);

            if (m_notitle == false && title.Length == 0)
                return(true);

            wndArray.Add(new Window(title.ToString(), (IntPtr)hWnd,  
                                    module.ToString()));

            return(true);
        }
         
        //implement IEnumerable
        public IEnumerator GetEnumerator()
        {
            return (IEnumerator)this;
        }
        //implement IEnumerator
        public bool MoveNext()
        {
            m_Position++;
            if (m_Position < wndArray.Count)
{
return true;
}
else
{
return false;
}
}
public void Reset()
{
m_Position = -1;
}
public object Current
{
get
{
return wndArray[m_Position];
}
}
}
}