.Net 文件名补位

文件以name-1.pdf、name-2.pdf、name-3.pdf......name-80.pdf命名，传到数据库中排序混乱：1之后为10，2之后是20，所以要把文件名中的数字补位变成相同位数，使排序按数字的递增来排序

   public string Cover(string sFileName,char flag)
         {
             string[] infos1 = sFileName.Split(flag);
             int n = infos1.Length;
             if (n > )
             {
                 string[] infos2 = infos1[n - ].Split('.');
                 string num = infos2[].PadLeft(, '');
                 int i;
                 string imagenamesuffix = "";
                 string imagenameprefix = "";
                 imagenamesuffix = num + '.' + infos2[];
                 for (i = ; i < n - ; i++)
                 {
                     imagenameprefix += infos1[i] + flag;
                 }
                 string name = imagenameprefix + imagenamesuffix;
                 sFileName = name;
             }
             return sFileName;
         }

调用

             int minsignFlag = sFileName.IndexOf("-");
             int underlineFlag = sFileName.IndexOf("_");

             if (minsignFlag > )
             {
                 sFileName = Cover(sFileName, '-');
             }
             if (underlineFlag > )
             {
                 sFileName = Cover(sFileName, '_');
             }