ToString 的字符string format格式

将指定的String 中的每个格式项替换为相应对象的值的文本等效项。

 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

http://skylaugh.cnblogs.com/archive/2006/04/05/367663.aspx