求救~~文本读写问题~~急急
文本内容如下: 
 aa 
 cc 
 vv 
 bb 
 (dd-ff-fdf) 
 ss   
 我想要把 "dd-ff "   读出来该怎么做?? 
 谢谢各位大虾们...急需~~
------解决方案--------------------try   
 using (StreamReader sr = new StreamReader(@ "e:\test.txt ", System.Text.Encoding.Default)) 
 { 
     bool flag = false; 
     while (sr.Peek() > = 0) 
     { 
         if (sr.ReadLine().IndexOf( "dd-ff ") >  -1) 
         { 
             MessageBox.Show( "存在 "); 
             flag = true; 
             break; 
         } 
     } 
     if (!flag) 
         MessageBox.Show( "不存在 "); 
 }