int aa = 11; string aastr = aa.ToString("000"); //或 string aastr = aa.ToString().PadLeft(3,'0'); //結果:011 int num=2; //三位,不足左側補零 string str = string.format("{0:d3}",num); //結果:002 string str1 = string.format("{0}{{1:d4}}","1001",12); //結果:10010012
轉:https://www.cnblogs.com/jiangyunfeng/p/13355677.html