ms-help://MS.MSDNQTR.2003FEB.2052/cpref/html/frlrfSystemConvertClassTopic.htm
// Returns "123.0"
string s = System.Convert.ToString(d);
// Returns "123.0"
string s = System.Convert.ToString(d);
string k=Convert.ToString(d);
double d = 123.0;
string str = d.ToString("f");
string s=string.Format ("{0:f4}",d);//4表示小数点后的位数,默认为2
double d=123324.0;
string str=(string)d;also use format
just do it as up told!and Convert ,also they have told you
string s=d.ToString("0.0");