[原]c# 读取文本文件(txt)

public void writeText(string txt)
  {
   StreamWriter sw=File.AppendText(fileName); 
   sw.WriteLine(txt+"\n");     
   sw.Close();
   
  }

  public string readText()
  {
   StreamReader sr=new StreamReader(fileName);  
   string sLine="";  
   StringBuilder sb=new StringBuilder();
   while(sLine   !=   null)  
   {  
    sLine=sr.ReadLine();  
    if(sLine!=null)  
     sb.Append(sLine+"\n");
   }  
   sr.Close();
   return sb.ToString();
  }