小鸟求教random方法的问题

Question

           int counta = 0;
           int countb = 0;
           int countc = 0;
           int a, b, c = rc.MR(out a, out b,out c);
           for (int i = 0; i < a+b+c; i++)
           {
              
             
               while (counta + countb + countc != a + b + c)
               { 
                   int X = rd.Next(1,3);
                   switch (X)
                   {
                       case 1:
                           {                               I.Images.Add(.new1());
                               counta++;
                               break;
                           }
                       case 2:
                           {
                               I.Images.Add(.new2());
                               countb++;
                               break;
                           }
                       case 3:
                           {
                               I.Images.Add(.new3());
                               countc++;
                               break;
                           }
                   }
               }
           }
这是我的代码 我测试完发现75次 随机到3的值一次没有 这是为什么

Answer 1

Next(a,b);Next生成大于等于a的数,小于b的数看下msdn吧！

Answer 2

int X = rd.Next(1,3);
表示随机产生一个大于等于1、且小于3的整数，也就是1或2，应改为int X = rd.Next(1,4);