怎样定义小数位数？

[xiaoslong]

比如我定义一个变量 double a; 然后赋植 a=53.5262;怎样才能指定变量a的小数位数为2，当用
Console.WriteLine(a)显示时，能自动转换为53.26。

[hxhbluestar]

//这是普通的字符串转换，小数位数在MyDouble.ToString("F")的F后面加数字就可以了，默认是两位的
using System;
using System.Threading;
using System.Globalization;

class Class1
{
static void Main()
{
Thread.CurrentThread.CurrentCulture = new CultureInfo("en-us");
double MyDouble = 123456789;

Console.WriteLine("The examples in en-US culture.\n");
Console.WriteLine(MyDouble.ToString("C"));
Console.WriteLine(MyDouble.ToString("E"));
Console.WriteLine(MyDouble.ToString("P"));
Console.WriteLine(MyDouble.ToString("N"));
Console.WriteLine(MyDouble.ToString("F"));

Thread.CurrentThread.CurrentCulture = new CultureInfo("de-DE");
Console.WriteLine("The examples in de-DE culture.\n");
Console.WriteLine(MyDouble.ToString("C"));
Console.WriteLine(MyDouble.ToString("E"));
Console.WriteLine(MyDouble.ToString("P"));
Console.WriteLine(MyDouble.ToString("N"));
Console.WriteLine(MyDouble.ToString("F"));
}
}
上述代码示例将下列内容显示到控制台。
The examples in en-US culture:
$123,456,789.00
1.234568E+008
12,345,678,900.00%
123,456,789.00
123456789.00
The examples in de-DE culture:
123.456.789,00 DM
1,234568E+008
12,345,678,900.00%
123.456.789,00
123456789,00



//这是用于要在货币值中使用的小数位数。InvariantInfo 的默认值为 2。
using System;
using System.Globalization;

class NumberFormatInfoSample {

public static void Main() {

// Gets a NumberFormatInfo associated with the en-US culture.
NumberFormatInfo nfi = new CultureInfo( "en-US", false ).NumberFormat;

// Displays a negative value with the default number of decimal digits (2).
Int64 myInt = -1234;
Console.WriteLine( myInt.ToString( "C", nfi ) );

// Displays the same value with four decimal digits.
nfi.CurrencyDecimalDigits = 4;
Console.WriteLine( myInt.ToString( "C", nfi ) );

}
}


/*
This code produces the following output.

($1,234.00)
($1,234.0000)
*/

[gully]

还有一种方法
string strInt = string.Format("{0:.00}",i); //显示两位小数,当小数部分为0时显示 .00
string strInt = string.Format("{0:.##}",i); //当小数部分为0时 不显示0.

占位符0 当输入为0时仍然显示0
占位符# 当输入为0时不显示

[elusion]

toString("F2");

[parol2910]

double a=23.5678;
Response.Write(a.ToString("F2"));


输出为２３．５７