本文实例讲述了C#小数点格式化用法。分享给大家供大家参考，具体如下：

1.ToString()方法

double d=12345678.2334; Console.WriteLine(d.ToString("F2")); //1234.23 Console.WriteLine(d.ToString("###,###.00")); //12,345,678.23

2.Math.Round()方法

Math.Round(3.44, 1); //Returns 3.4. Math.Round(3.45, 1); //Returns 3.4. Math.Round(3.46, 1); //Returns 3.5. Math.Round(3.445, 1); //Returns 3.4. Math.Round(3.455, 1); //Returns 3.5. Math.Round(3.465, 1); //Returns 3.5. Math.Round(3.450, 1); //Returns 3.4.(补0是无效的) Math.Round(3.4452, 2); //Returns 3.45. Math.Round(3.4552, 2); //Returns 3.46. Math.Round(3.4652, 2); //Returns 3.47.

"四舍六入五考虑，五后非零就进一，五后皆零看奇偶，五前为偶应舍 去，五前为奇要进一"

短一点的口诀叫“四舍、六入、五凑偶”

3.double.Parse()方法

double d=1.12345; d=double.Parse(d.ToString("0.00")); //1.12

4.输出百分号

System.Globalization.NumberFormatInfo provider = new System.Globalization.NumberFormatInfo(); provider.PercentDecimalDigits = 2;//小数点保留几位数. provider.PercentPositivePattern = 1;//百分号出现在何处. double result = (double)1 / 3;//一定要用double类型. Console.WriteLine(result.ToString("P", provider)); //33.33% //或 Console.WriteLine((result*100).ToString("#0.#0")+"%");

5.String.Format()方法

string str1 = String.Format("{0:N1}",56789); //result: 56,789.0 string str2 = String.Format("{0:N2}",56789); //result: 56,789.00 string str3 = String.Format("{0:N3}",56789); //result: 56,789.000 string str8 = String.Format("{0:F1}",56789); //result: 56789.0 string str9 = String.Format("{0:F2}",56789); //result: 56789.00 string str11 =(56789 / 100.0).ToString("#.##"); //result: 567.89 string str12 =(56789 / 100).ToString("#.##"); //result: 567

希望本文所述对大家C#程序设计有所帮助。