[C#]统计文本文件txt中的行数，快速读取

快速统计文本文件中的行数( StreamReader.ReadLine() ):

测试代码如下：

 1 　　     //读取txt文件中总行数的方法
 2         public static int requestMethod(String _fileName)
 3         {
 4             Stopwatch sw = new Stopwatch();
 5             var path = _fileName;
 6             int lines = 0;
 7 
 8             //按行读取
 9             sw.Restart();
10             using (var sr = new StreamReader(path))
11             {
12                 var ls = "";
13                 while ((ls = sr.ReadLine()) != null)
14                 {
15                     lines++;
16                 }
17             }
18             sw.Stop();
19             return lines;
20         }