//有关数字格式化隐性使用IFomatProvider的例子#if true            //货币            Console.WriteLine(string.Format("显示货币格式{0:c3}",12));            //十进制            Console.WriteLine("显示货币十进制格式{0:d10}", 12);            //科学计数法            Console.WriteLine("科学计数法{0:e5}",12);            //固定点格式            Console.WriteLine("固定点格式 {0:f10}",12);            //常规格式            Console.WriteLine("常规格式{0:g10}",12);            //数字格式(用分号隔开)            Console.WriteLine("数字格式 {0:n5}:",666666666);            //百分号格式            Console.WriteLine("百分号格式(不保留小数){0:p0}",0.55);            //16进制            Console.WriteLine("16进制{0:x0}", 12);           // 0定位器  此示例保留5位小数，如果小数部分小于5位，用0填充            Console.WriteLine("0定位器{0:000.00000}",1222.133);            //数字定位器            Console.WriteLine("数字定位器{0:(#).###}", 0200.0233000);             //小数            Console.WriteLine("小数保留一位{0:0.0}", 12.222);            //百分号的另一种写法，注意小数的四舍五入            Console.WriteLine("百分号的另一种写法，注意小数的四舍五入{0:0%.00}", 0.12345);            Console.WriteLine("\n\n"); #endif

#if true            //显性使用IFomatProvider            Console.WriteLine("显性使用IFomatProvider的例子");            //实例化numberFomatProvider对象            NumberFormatInfo numberFomatProvider = new NumberFormatInfo();            //设置该provider对于货币小数的显示长度            numberFomatProvider.CurrencyDecimalDigits = 10;            //注意：我们可以使用C+数字形式来改变provider提供的格式            Console.WriteLine(string.Format(numberFomatProvider, "provider设置的货币格式{0:C}", 12));            Console.WriteLine(string.Format(numberFomatProvider, "provider设置的货币格式被更改了：{0:C2}", 12));            Console.WriteLine(string.Format(numberFomatProvider, "默认百分号和小数形式{0:p2}", 0.12));            //将小数 “.”换成"?"              numberFomatProvider.PercentDecimalSeparator = "?";             Console.WriteLine(string.Format(numberFomatProvider, "provider设置的百分号和小数形式{0:p2}", 0.12));            Console.ReadLine();#endif

  const string txtFilePath = "D:\\TextWriter.txt";

        static void Main(string[] args)        {

            NumberFormatInfo numberFomatProvider = new NumberFormatInfo();            //将小数 “.”换成"?"             numberFomatProvider.PercentDecimalSeparator = "?";            StreamWriterTest test = new StreamWriterTest(Encoding.Default, txtFilePath, numberFomatProvider);            //StreamWriter            test.WriteSomthingToFile();            //TextWriter            test.WriteSomthingToFileByUsingTextWriter();            Console.ReadLine();        }    }

    /// <summary>    ///  TextWriter和StreamWriter的举例    /// </summary>    public class StreamWriterTest    {        /// <summary>        /// 编码        /// </summary>        private Encoding _encoding;

        /// <summary>        /// IFomatProvider        /// </summary>        private IFormatProvider _provider;

        /// <summary>        /// 文件路径        /// </summary>        private string _textFilePath;

        public StreamWriterTest(Encoding encoding, string textFilePath)            : this(encoding, textFilePath, null)        {

        }

        public StreamWriterTest(Encoding encoding, string textFilePath, IFormatProvider provider)        {            this._encoding = encoding;            this._textFilePath = textFilePath;            this._provider = provider;        }

        /// <summary>        ///  我们可以通过FileStream 或者 文件路径直接对该文件进行写操作        /// </summary>        public void WriteSomthingToFile()        {            //获取FileStream            using (FileStream stream = File.OpenWrite(_textFilePath))            {                //获取StreamWriter                using (StreamWriter writer = new StreamWriter(stream, this._encoding))                {                    this.WriteSomthingToFile(writer);                }

                //也可以通过文件路径和设置bool append，编码和缓冲区来构建一个StreamWriter对象                using (StreamWriter writer = new StreamWriter(_textFilePath, true, this._encoding, 20))                {                    this.WriteSomthingToFile(writer);                }            }        }

        /// <summary>        ///  具体写入文件的逻辑        /// </summary>        /// <param name="writer">StreamWriter对象</param>        public void WriteSomthingToFile(StreamWriter writer)        {            //需要写入的数据            string[] writeMethodOverloadType =           {              "1.Write(bool);",              "2.Write(char);",              "3.Write(Char[])",              "4.Write(Decimal)",              "5.Write(Double)",              "6.Write(Int32)",              "7.Write(Int64)",              "8.Write(Object)",              "9.Write(Char[])",              "10.Write(Single)",              "11.Write(Char[])",              "12.Write(String)",              "13Write(UInt32)",              "14.Write(string format,obj)",              "15.Write(Char[])"           };

            //定义writer的AutoFlush属性，如果定义了该属性，就不必使用writer.Flush方法            writer.AutoFlush = true;            writer.WriteLine("这个StreamWriter使用了{0}编码", writer.Encoding.HeaderName);            //这里重新定位流的位置会导致一系列的问题            //writer.BaseStream.Seek(1, SeekOrigin.Current);            writer.WriteLine("这里简单演示下StreamWriter.Writer方法的各种重载版本");

            writeMethodOverloadType.ToList().ForEach                (                    (name) => { writer.WriteLine(name); }                );            writer.WriteLine("StreamWriter.WriteLine()方法就是在加上行结束符，其余和上述方法是用一致");            //writer.Flush();            writer.Close();        }

        public void WriteSomthingToFileByUsingTextWriter()        {            using (TextWriter writer = new StringWriter(_provider))            {                writer.WriteLine("这里简单介绍下TextWriter 怎么使用用户设置的IFomatProvider，假设用户设置了NumberFormatInfoz.PercentDecimalSeparator属性");                writer.WriteLine("看下区别吧 {0:p10}", 0.12);                Console.WriteLine(writer.ToString());                writer.Flush();                writer.Close();            }

        }    }