C#認識/理解/運用 StreamReader,StreamWriter,StringReader,StringWriter[轉]

題記

StreamReader,StreamWriter,StringReader,StringWriter每次看到這幾個詞的時候，就會混淆（理解不夠深刻），在使用過程中也經常犯渾，為了能更好的理解，寫下此文章。

正文

概念

首先，從字面可以看出，StreamReader,StringReader是用來讀操作，StreamWriter,StringWriter是用來寫操作。

接下來看這幾個類在類庫中的層次

上圖中，StreamReader,StringReader都派生自TextReader類（TextReader：表示可讀取連續字符序列的讀取器。抽象基類）

StreamReader從流中讀取字符

StringReader從字符串讀取字符

上圖中，StreamWriter,StringWriter派生自TextWriter類（TextWriter：表示可以編寫一個有序字符序列的編寫器。該類為抽象類。）

StreamWriter將字符寫入流

StringWriter將字符寫入字符串

代碼

reader操作

        private static void StringRead()
        {
            string in_str ="流操作，字符操作，io操作";
            string read_str, aParagraph = null;
            StringReader sr = new StringReader(in_str);
            while (true)
            {
                read_str = sr.ReadLine();
                if (read_str != null)
                {
                    aParagraph = aParagraph + in_str + " ";
                }
                else
                {
                    aParagraph = aParagraph + "\n";
                    break;
                }
            }
        }

        private static void StreamRead()
        {
            Stream rStream = new FileStream(@"E:/20120214.txt", FileMode.Open);
            StreamReader sr = new StreamReader(rStream, Encoding.UTF8);
            //從流中讀取字符
            string result = sr.ReadToEnd();
            //釋放資源
            sr.Close();
            rStream.Close();
        }

 

writer操作

        private static void StreamWriter()
        {
            string in_str = DateTime.Now.ToString("MM-dd HH:mm:ss:fff");
            //第二個參數  是否追加
            StreamWriter sw = new StreamWriter(@"E:/20120214.txt",true,Encoding.Default);
            sw.Write(in_str);
            sw.Flush();
            sw.Close();
        }
        
        private static void StringWriter()
        {            
            StringWriter sw = new StringWriter();
            sw.Write("文字，學習，文字，c#");
            sw.Close();
        }