C# 小数位数保留的方法集锦

  1.System.Globalization.NumberFormatInfo provider = new System.Globalization.NumberFormatInfo();

  provider.NumberDecimalDigits =intDecLength; //要设定的小数位数

  double strCashAmt=Convert.ToDouble(this.txtCashAmt.Text); //先把控件內的值转成double

  this.txtCashAmt.Text = strCashAmt.ToString("N",provider); //再利用ToString函数格式化小数位数

  2.保留N位,四舍五入 .

  decimal d= decimal.Round(decimal.Parse("0.55555"),2);

  3.保留N位四舍五入

  Math.Round(0.55555,2)

  4,保留N位四舍五入

  double dbdata = 0.55555;

  string str1 = dbdata.ToString("f2");//fN 保留N位,四舍五入

  5.保留N位四舍五入

  string result = String.Format("{0:N2}", 0.55555);//2位

  string result = String.Format("{0:N3}", 0.55555);//3位

  6. 保留N位四舍五入 (不错)

  double s=0.55555;

  result=s.ToString("#0.00");//点后面几个0就保留几位

  C#下如果显示保留小数位数,及百分号的解决方法:

  1、用NumberFormatInfo类来解决:

  System.Globalization.NumberFormatInfo provider = new System.Globalization.NumberFormatInfo();

  provider.PercentDecimalDigits = 2;//小数点保留几位数.

  provider.PercentPositivePattern = 2;//百分号出现在何处.

  double result = (double)1 / 3;//一定要用double类型.

  Response.Write(result.ToString("P", provider));

  2、用toString方法.:

  public string getRate(double hcount, double task)

  {

  string rValue;

  string temp = "";

  if (task == 0)

  {

  task = 1;

  }

  double db = (hcount / task) * 100;

  if (hcount >= task)

  {

  rValue = "100%";

  }

  else

  {

  rValue = db.ToString("#0.#0") + "%";

  }

  return rValue;

  }

  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