C#学习笔记---区分StringWriter(Reader)和StreamWriter(Reader)，TextWriter(Reader)，BinaryWriter(Reader)

1.TextWriter(Reader)分别是对连续字符系列处理的编写器（读写器），来自System.IO

2.StringWriter(Reader)继承TextWriter(Reader)，它主要是对字符串进行处理的类，样例如下：

            TextWriter stringwriter = new StringWriter();
            stringwriter.Write("你好，通过StringWriter写入，StringWriter继承TextWriter");
            TextReader stringreader = new StringReader(stringwriter.ToString());
            Console.WriteLine("从{0}——{1}", stringreader.GetType().Name, stringreader.ReadToEnd());
            Console.WriteLine();

3.StreamWriter(Reader)也继承TextWriter(Reader)，它主要是以流的形式处理数据，可以是记忆流，文件流，系列端口流以及媒体视频流等。例子：

            using (TextWriter streamwriter = new StreamWriter("mytext.txt"))
            {
                streamwriter.Write("你好，通过StreamWriter写入，StreamWriter继承TextWriter");
            }
            TextReader streamreader = new StreamReader("mytext.txt");
            Console.WriteLine("从{0}——{1}", streamreader.GetType().Name, streamreader.ReadToEnd());
            Console.ReadLine();

4.BinaryWriter(Reader)不继承TextWriter(Reader)，以二进制形式讲基元类型写入（读取），并支持特定的编码，其有广泛的支持形式，因为它以二进制方式读取写入。例子：

            //BinaryWriter(Reader)
            const string filename = "test.txt";
            if (File.Exists(filename))
            {
                Console.WriteLine("{0}文件已存在！", filename);
            }
            FileStream fs = new FileStream(filename, FileMode.Create);
            BinaryWriter bw = new BinaryWriter(fs);
            string str = Environment.CurrentDirectory + @"QQ.EXE.lnk";
            bw.Write(str);
            bw.Close();
            fs.Close();
            //现在开始读取
            fs = new FileStream(filename, FileMode.Open, FileAccess.Read);
            BinaryReader br = new BinaryReader(fs);
            long size = br.BaseStream.Length;
            byte[] bytesize = new byte[size];
            bytesize = br.ReadBytes((int)size);
            Console.WriteLine(bytesize.ToString());
            br.Close();
            fs.Close();
            Console.ReadLine();

下面再示一例BinaryWriter写入XML信息例子：

            const string filename = "XmlWriter1.xml";
            FileStream fs = new FileStream(filename, FileMode.Create);
            BinaryWriter bw = new BinaryWriter(fs);
            XmlElement ee = xdoc.DocumentElement;
            if (ee != null)
            {
                bw.Write(ee.OuterXml);
            }
            else
            {
                Console.WriteLine("获取对象失败！");
            }
            bw.Close();
            fs.Close();