需求：为控制会议时间，采取ppt幻灯片播放倒计时的办法，倒计时5分钟。
分析：用EnumWindows枚举窗口，发现PPT窗口类名有三种：PP12FrameClass、MS-SDIb、screenClass。其中screenClass代表全屏播放窗口。
设计思路：在timer控件中用FindWindow检查有无screenClass的窗口，用TimeSpan倒计时。
设计成一个托盘程序，用一个notifyIcon和contextMenuStrip关联。
代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms;
using System.Text.RegularExpressions;
using System.IO; namespace pptClock
{ //使用说明：用于ＰＰＴ倒计时的winform。将播放的ＰＰＴ文件名最后加上数字，表示播放限时的分钟数。若数字为０或无数字表示不限时。
public partial class Form1 : Form
{
//相关的win32 api
[DllImport("user32.dll")]
private static extern int GetWindowTextW(IntPtr hWnd, [MarshalAs(UnmanagedType.LPWStr)]StringBuilder lpString, int nMaxCount);
[DllImport("user32.dll")]
private static extern int GetClassNameW(IntPtr hWnd, [MarshalAs(UnmanagedType.LPWStr)]StringBuilder lpString, int nMaxCount);
[DllImport("user32.dll", EntryPoint = "FindWindow")]
private extern static IntPtr FindWindow(string lpClassName, string lpWindowName);
public const int WM_CLOSE = 0x10;
[DllImport("user32.dll", EntryPoint = "SendMessageA")]
public static extern int SendMessage(IntPtr hwnd, int wMsg, int wParam, int lParam); //全屏播放ＰＰＴ窗口信息
public struct WindowInfo
{
public IntPtr hWnd; //ppt窗口句柄
public string szWindowName;//窗口标题
public string szClassName;//类名：screenClass ,实际没有用。
public int timeL; //播放限时，从文件名中获取
} public bool hasscreenClass() //是否有全屏播放ＰＰＴ
{
bool yn = false;
IntPtr hwnd = FindWindow("screenClass", null);
if (hwnd != IntPtr.Zero)//有全屏的ＰＰＴ
{
yn = true;
//则将窗口信息保存到wndfullscreen中
StringBuilder sb = new StringBuilder();
//get hwnd
wndfullscreen.hWnd = hwnd;
//get window name
GetWindowTextW(hwnd, sb, sb.Capacity);
wndfullscreen.szWindowName = sb.ToString();
//get window class
GetClassNameW(hwnd, sb, sb.Capacity);
wndfullscreen.szClassName = sb.ToString();
Match result = Regex.Match(wndfullscreen.szWindowName.ToLower(), @"\d{1,2}(?=.ppt)", RegexOptions.RightToLeft);
string r = result.Value;
int timeL;
if (r != "")
{
timeL = int.Parse(r);
}else
{
timeL = ;
}
wndfullscreen.timeL = timeL; }
return yn;
} WindowInfo wndfullscreen = new WindowInfo();//用于保存正在全屏播放的窗口信息
TimeSpan ts = new TimeSpan(); //保存播放倒计时
bool playflag = false; //播放flag;
bool rtimeflag = false; //是否对播放的ppt限时的flag; public Form1()
{
InitializeComponent();
} private void 退出ToolStripMenuItem_Click(object sender, EventArgs e)
{
this.Close();
} private void Form1_Load(object sender, EventArgs e)
{
//this.Hide = true;
this.ShowInTaskbar = false;
timer1.Interval = ;
this.Top = ;
Rectangle ScreenArea = System.Windows.Forms.Screen.GetBounds(this);
int width1 = ScreenArea.Width; //屏幕宽度
int width2 = this.Width;
this.Left = width1 - width2-;//定位到屏幕右上角
timer1.Enabled = true; //开始计时
this.TopMost = true;//显示在最前 } private void timer1_Tick(object sender, EventArgs e)
{
if (playflag == false && hasscreenClass())//说明是刚开始播放
{
playflag = true;
int timeL = wndfullscreen.timeL;
if(timeL > )
{
rtimeflag = true; //表明要对本ppt进行倒计时
ts = new TimeSpan(, wndfullscreen.timeL,); //设定倒计时时间
}
}
if (playflag == true && rtimeflag == true) //正在播放且需要进行限时
{
ts = ts.Subtract(new TimeSpan(, , ));//倒计时，每隔一秒减去一秒
String str = ts.Minutes.ToString() + ":" + ts.Seconds.ToString();
this.label1.Text = str;
}else //不限时，则显示时钟
{
String str = DateTime.Now.Hour.ToString() + ":"+ DateTime.Now.Minute.ToString() + ":" + DateTime.Now.Second.ToString();
this.label1.Text = str; }
//用户提前退出ppt
if (playflag == true && !hasscreenClass())
{
playflag = false;
rtimeflag = false; }
//倒计时结束
if (ts.TotalSeconds < 0.0 && hasscreenClass())//当倒计时完毕
{
IntPtr hwnd_win = wndfullscreen.hWnd;
SendMessage(hwnd_win, WM_CLOSE, , );//发送退出消息
playflag = false;
rtimeflag = false; } } private void 设置ToolStripMenuItem_Click(object sender, EventArgs e)
{
//选择播放目录
string fullfname, extension;
string path = string.Empty;
System.Windows.Forms.FolderBrowserDialog fbd = new System.Windows.Forms.FolderBrowserDialog();
if (fbd.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
path = fbd.SelectedPath;
} if (path != string.Empty)
{
DirectoryInfo di = new DirectoryInfo(path);
foreach (var fi in di.GetFiles())
{
extension =fi.Extension.ToLower();
if(extension == ".ppt" || extension == ".pptx")
{
try
{
fullfname = fi.FullName;
//修改文件名加上“限时”
if (fullfname.Contains("安全环保部"))
{
fi.MoveTo(fullfname + "_限时8" + extension);
}
else
{
fi.MoveTo(fullfname + "_限时5" + extension);
}
//打开目录
System.Diagnostics.Process.Start(fi.DirectoryName);
}
catch { } } } } } }
}
补充：增加了可拖动窗口的代码如下：
//处理拖动
protected override void WndProc(ref Message m)
{
if(m.Msg == 0x0201){//鼠标左键按下
m.Msg = 0x00A1; //更改消息为非客户区按下鼠标
m.LParam = IntPtr.Zero; //默认值
m.WParam = new IntPtr(); //鼠标放在标题栏内 }
base.WndProc(ref m);
}