int r = 0;
            int count = 0;
            while (count <= 1)
            {
                Random rd = new Random();
                r = rd.Next(1000000, 9999999);
               
int q = r / 1000000; int w = r / 100000 % 10; int e = r / 10000 % 100; int t = r / 1000 % 1000; int y = r / 100 % 10000; int u = r / 10 % 100000; int o = r % 1000000;
                int[] num = new int[7] { q, w, e, t, y, u, o };
                for (int i = 0; i < 7; i++)
                {
                    for (int j = i + 1; j < 7; j++)
                    {
                        if (num[i] == num[j])
                        {
                            break;
                        }
                    }
                    count += 1;   
                }
                Console.WriteLine(r);
                 }            
我要求得是一个不同数字的7位数，不知道错在哪？

分别模10即可  （你是不是想提取比如  1234567  的1,2,3,4,5,6,7

是啊