总结C#保留小数位数及百分号处理

方法一：
    decimal d= decimal.Round(decimal.Parse("0.55555"),2);  
方法二：
Math.Round(0.55555,2)  
方法三：
double dbdata = 0.55555;   
string str1 = dbdata.ToString("f2");//fN 保留N位，四舍五入 
方法四：
string result = String.Format("{0:N2}", 0.55555);//2位   
 
string result = String.Format("{0:N3}", 0.55555);//3位 
方法五：
double s=0.55555;   
result=s.ToString("#0.00");//点后面几个0就保留几位 

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 

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));