初学者一个StreamWriter的问题哈,不知道该怎么写
一个TEXTBOX   一个BUTTON      在TEXTBOX里输入信息后,点BUTTON后把TEXTBOX里的信息保存在 
 D盘下的123文件的123.TXT里,   如果没有123.TXT的话,自动创建   
 在次输入信息的时候记录在123.TXT里的第二行   
 代码该如何写?各位前辈帮帮忙吧 
 private   void   button1_Click(object   sender,   System.EventArgs   e) 
 		{ 
 		   StreamWriter   sw   =new   StreamWriter(); 
                                                          ....................................    			 
 		}
------解决方案--------------------string path = @ "d:\123.txt "; 
 System.IO.StreamWriter sw = null; 
 if(!System.IO.File.Exists(path)) 
 	sw = System.IO.File.CreateText(path); 
 else 
 	sw = System.IO.File.AppendText(path);  			 
 sw.WriteLine(textBox1.Text); 
 sw.Close();
------解决方案--------------------不好意思没看清搂主意思  
    paths = Directory.GetCurrentDirectory()+ "\\ Bak.txt ";      
             FileStream sour=new FileStream(paths ,FileMode .OpenOrCreate  ,FileAccess .ReadWrite );// 如果没有就创建 
            StreamReader  Myfile= new StreamReader(sour ,false,Encoding .Default ); 
 myfile.writeline(textbox.txt); 
 myfile.close();
------解决方案--------------------writeline 
 就行了 
 给你一段参考一下 
         private void SaveListBox(ListBox listBox,string defaultSaveName) 
         { 
             SaveFileDialog saveScanResult = new SaveFileDialog(); 
             saveScanResult.Filter =  "txt|*.txt "; 
             saveScanResult.Title =  "Save the List "; 
             saveScanResult.FileName = defaultSaveName; 
             if (saveScanResult.ShowDialog() == DialogResult.OK) 
             //saveScanResult.ShowDialog(); 
             { 
                 if (saveScanResult.FileName !=  " ") 
                 { 
                     using (StreamWriter sw = new StreamWriter(saveScanResult.FileName)) 
                     { 
                         sw.WriteLine( "The content of list is: "); 
                         sw.WriteLine( "Save Date: "); 
                         sw.WriteLine(DateTime.Now); 
                         sw.WriteLine( "-------------------------- ");   
                         for (int i = 0; i  < listBox.Items.Count; i++) 
                         { 
                             sw.WriteLine(listBox.Items[i].ToString()); 
                         } 
                         sw.Close(); 
                         MessageBox.Show( "The result has been saved! "); 
                     }   
                 } 
             } 
         }   
 存完结果是这个模样的 
 The content of list is: 
 Save Date: 
 2007-3-26 21:51:58 
 -------------------------- 
 169.254.179.1::::::000000000000 
 169.254.179.2::::::000000000000 
 169.254.179.3::::::000000000000 
 169.254.179.4::::::000000000000 
 169.254.179.5::::::000000000000 
 169.254.179.6::::::000000000000