C# 标准数字格式字符串

 测试代码：

                    //数字格式字符串
                    Console.WriteLine("数字格式字符串");
                    Console.WriteLine("====================G或g====================");
                    Console.WriteLine(string.Format("{0:G}", 1.2345)); 
                    Console.WriteLine(string.Format("{0:G}", 0.00001)); 
                    Console.WriteLine(string.Format("{0:g}", 0.00001)); 
                    Console.WriteLine(string.Format("{0:G3}", 1.2345)); 
                    Console.WriteLine(string.Format("{0:G}", 12345));
                    Console.WriteLine("====================F====================");
                    Console.WriteLine(string.Format("{0:F2}",2345.678));
                    Console.WriteLine(string.Format("{0:F2}",2345.6));
                    Console.WriteLine("====================N====================");
                    Console.WriteLine(string.Format("{0:N2}",2345.678));
                    Console.WriteLine(string.Format("{0:N2}",2345.6));
                    Console.WriteLine("====================D====================");
                    Console.WriteLine(string.Format("{0:D5}",123));
                    Console.WriteLine(string.Format("{0:D1}",123));
                    Console.WriteLine("====================E或e====================");
                    Console.WriteLine(string.Format("{0:E}",56789));
                    Console.WriteLine(string.Format("{0:e}", 56789));
                    Console.WriteLine(string.Format("{0:E2}", 56789));
                    Console.WriteLine("====================C====================");
                    Console.WriteLine(string.Format("{0:C}",1.2));
                    Console.WriteLine(string.Format("{0:C4}",1.2));
                    Console.WriteLine("====================P====================");
                    Console.WriteLine(string.Format("{0:P}",0.503));
                    Console.WriteLine(string.Format("{0:P0}",.503));
                    Console.WriteLine("====================X或x====================");
                    Console.WriteLine(string.Format("{0:X}",47));
                    Console.WriteLine(string.Format("{0:f}",47));
                    Console.WriteLine(string.Format("{0:X4}",47));
                    Console.WriteLine("====================R或G17====================");
                    Console.WriteLine(string.Format("{0:R}",1f/3f));
                    Console.WriteLine(string.Format("{0:G17}",1f/3f));

测试结果