[转载]C# ToString格式字符串整理Format数字、日期和枚举的标准格式设置说明符

[转载]C# ToString格式字符串整理(Format)(数字、日期和枚举的标准格式设置说明符)(SamWang) – SamWang – 博客园.

日常开发中，格式字符串的情况非常多。经常也会忘记，经常去查有些麻烦，所以今天就花点时间做个整理。

格式字符串用的比较多的有数字、日期与枚举的格式化。

　一、数字格式字符串

先用例子说明几种格式字符串的方法：

double d = 123.456;
Console.WriteLine("ToString:{0}", d.ToString("C"));
Console.WriteLine("Format:{0}", string.Format("{0:C}",d));
Console.WriteLine("Console:{0:C}", d);

输出结果：

数字格式化程序例子：

Console.WriteLine("十六进制格式符X：{0}", (145).ToString("X"));//X只支持整型
double[] numbers = {1054.32179, -195489100.8377, 1.0437E21,
-1.0573e-05};
string[] specifiers = { "C", "E", "F", "G", "N","P",
"R","#,000.000", "0.###E-000",
"000,000,000,000.00###" };
foreach (double number in numbers)
{
Console.WriteLine("Formatting of {0}:", number);
foreach (string specifier in specifiers)
{
Console.WriteLine(" {0,5}: {1}",
specifier, number.ToString(specifier));
}
Console.WriteLine();
}

输出结果：

MSDN:Double.ToString 方法 (String)

　 二、日期格式字符串

static void DateToString()
{
DateTime dateValue = DateTime.Now;
// Create an array of standard format strings.
string[] standardFmts = {"d", "D", "f", "F", "g", "G", "m", "o",
"R", "s", "t", "T", "u", "U", "y"};
// Output date and time using each standard format string.
foreach (string standardFmt in standardFmts)
Console.WriteLine("{0}: {1}", standardFmt,
dateValue.ToString(standardFmt));
Console.WriteLine();

// Create an array of some custom format strings.
string[] customFmts = {"yyyyMMddHHmmss","h:mm:ss.ff t", "d MMM yyyy", "HH:mm:ss.f",
"dd MMM HH:mm:ss", @"\Mon\t\h\: M", "HH:mm:ss.ffffzzz" };
// Output date and time using each custom format string.
foreach (string customFmt in customFmts)
Console.WriteLine("'{0}': {1}", customFmt,
dateValue.ToString(customFmt));
}

输出结果：

　　　　MSDN:DateTime.ToString 方法 (String)

三、枚举格式字符串

enum Colors { Red, Green, Blue, Yellow = 12 };
static void EnumToString()
{
Colors myColor = Colors.Yellow;

Console.WriteLine("Colors.Red = {0}", Colors.Red.ToString("d"));
Console.WriteLine("Colors.Green = {0}", Colors.Green.ToString("d"));
Console.WriteLine("Colors.Blue = {0}", Colors.Blue.ToString("d"));
Console.WriteLine("Colors.Yellow = {0}", Colors.Yellow.ToString("d"));

Console.WriteLine("{0}myColor = Colors.Yellow{0}", Environment.NewLine);

Console.WriteLine("myColor.ToString(\"g\") = {0}", myColor.ToString("g"));
Console.WriteLine("myColor.ToString(\"G\") = {0}", myColor.ToString("G"));

Console.WriteLine("myColor.ToString(\"x\") = {0}", myColor.ToString("x"));
Console.WriteLine("myColor.ToString(\"X\") = {0}", myColor.ToString("X"));

Console.WriteLine("myColor.ToString(\"d\") = {0}", myColor.ToString("d"));
Console.WriteLine("myColor.ToString(\"D\") = {0}", myColor.ToString("D"));

Console.WriteLine("myColor.ToString(\"f\") = {0}", myColor.ToString("f"));
Console.WriteLine("myColor.ToString(\"F\") = {0}", myColor.ToString("F"));
}

输出结果：

MSDN：Enum.ToString 方法 (String)