你可以把格式传递给ToString方法，例如:

myFloatVariable.ToString("0.00"); //2dp Number

myFloatVariable.ToString("n2"); // 2dp Number

myFloatVariable.ToString("c2"); // 2dp currency

标准数字格式字符串

String.Format(“{0:#,# # #。# #}”,值)

下面是c#中字符串格式化的一个更复杂的例子:

String.Format(“{0:$ #,# # 0.00;($ #,# # 0.00);零}”,值); 如果通过1243.50，将输出“$1,240.00″”。如果数字为负数，它将输出相同的格式，但在括号中，如果数字为零，它将输出字符串“Zero”。

我相信:

String.Format("{0:0.00}",Sale);

应该这么做。

看到链接 字符串格式示例c#

您需要做的第一件事是使用十进制类型而不是浮点类型来计算价格。使用浮点数是绝对不可接受的，因为它不能准确地表示大多数小数。

一旦你这样做了，Decimal.Round()可以用来四舍五入到2位。

这适用于你想要使用插值字符串的情况。实际上，我发布这个是因为我厌倦了反复试验，最终每次我需要格式化某个标量时都要翻阅大量的文档。

$"{1234.5678:0.00}"        "1234.57"        2 decimal places, notice that value is rounded
$"{1234.5678,10:0.00}"     "   1234.57"     right-aligned
$"{1234.5678,-10:0.00}"    "1234.57   "     left-aligned
$"{1234.5678:0.#####}"     "1234.5678"      5 optional digits after the decimal point
$"{1234.5678:0.00000}"     "1234.56780"     5 forced digits AFTER the decimal point, notice the trailing zero
$"{1234.5678:00000.00}"    "01234.57"       5 forced digits BEFORE the decimal point, notice the leading zero
$"{1234.5612:0}"           "1235"           as integer, notice that value is rounded
$"{1234.5678:F2}"          "1234.57"        standard fixed-point
$"{1234.5678:F5}"          "1234.56780"     5 digits after the decimal point, notice the trailing zero
$"{1234.5678:g2}"          "1.2e+03"        standard general with 2 meaningful digits, notice "e"
$"{1234.5678:G2}"          "1.2E+03"        standard general with 2 meaningful digits, notice "E"
$"{1234.5678:G3}"          "1.23E+03"       standard general with 3 meaningful digits
$"{1234.5678:G5}"          "1234.6"         standard general with 5 meaningful digits
$"{1234.5678:e2}"          "1.23e+003"      standard exponential with 2 digits after the decimal point, notice "e"
$"{1234.5678:E3}"          "1.235E+003"     standard exponential with 3 digits after the decimal point, notice "E"
$"{1234.5678:N2}"          "1,234.57"       standard numeric, notice the comma
$"{1234.5678:C2}"          "$1,234.57"      standard currency, notice the dollar sign
$"{1234.5678:P2}"          "123,456.78 %"   standard percent, notice that value is multiplied by 100
$"{1234.5678:2}"           "2"              :)

性能警告

插值字符串很慢。根据我的经验，顺序是(快到慢):

value.ToString(format)+" blah blah" 字符串。格式("{0:Format} blah blah"， value) $"{value:format} blah blah"

    private float LimitDecimalPlace(double number,int limitPlace)
    {
        float result = 0;
        string sNumber = number.ToString();
        int decimalIndex = sNumber.IndexOf(".");
        if (decimalIndex != -1)
        {
            sNumber = sNumber.Remove(decimalIndex + limitPlace + 1);
        }
       
        result = float.Parse(sNumber);
        return result;
    }