string filename= this.txtFilename.Text;      
            StreamReader sr = new StreamReader(filename,System.Text.Encoding.Default);    
    
            try     
            {      
                sr.BaseStream.Seek(0,SeekOrigin.Begin);  
                //     从数据流中读取每一行，直到文件的最后一行，并在richTextBox1中显示出内容    
                string strLine = sr.ReadLine();  
                this.txtContent.Clear();
                while(strLine != null) 
                {   
    
                    this.txtContent.Text += strLine + "\n"; //这个换行符好像不起作用。
                    strLine = sr.ReadLine();
                }   
                //关闭此StreamReader对象   
                sr.Close();         
    
            }     
            catch(IOException)     
            {     
              
            }     
            finally     
            {     
                if(sr!=null)     
                    sr.Close();     
            }