FileSystemWatcher mywatch= new FileSystemWatcher(); mywatch.Path="f:\\";

//the file that is watched is what type
mywatch.Filter="*.doc";
//add event

mywatch.Changed+=new FileSystemEventHandler(this.change_do);

//start watch
mywatch.EnableRaisingEvents=true;
private void change_do(object sender, System.IO.FileSystemEventArgs e)
{
string s=e.Name.ToString();
s=s.Replace("~$","");
if(s=="新建文件夹.doc")
  MessageBox.Show(e.FullPath.ToString()+" 已改变! ","chang提示");
}