private static int randomCount = 0;
        private static string CreateRandomText()
        {
            randomCount++;

            Guid guid = Guid.NewGuid( );

            int key1 = guid.GetHashCode( );
            int key2 = unchecked( (int)DateTime.Now.Ticks );

            int seed = unchecked( key1 * key2 * randomCount );
            Random rand = new Random( seed );

            int n = rand.Next( 100000, 999999 );
            string sn = n.ToString( );
            for ( int j = 0 ; j < 6 ; j++ )
            {
                char ch = Convert.ToChar( rand.Next( 65, 90 ) );
                if ( ch == 'E' || ch == 'O' || ch == 'S' || ch == 'B' || ch == 'I' 
                    || ch == 'L' || ch == 'D' || ch == 'C' || ch == 'G' )
                {
                    break;
                }
                sn = sn.Replace( rand.Next( 1, 9 ).ToString( ), ch.ToString( ) );
            }
            sn = sn.Replace( "0", rand.Next( 2, 9 ).ToString( ) );
            sn = sn.Replace( "1", rand.Next( 2, 9 ).ToString( ) );
            sn = sn.Replace( "5", rand.Next( 6, 9 ).ToString( ) );

            return sn;
        }

------解决方案--------------------
 public int[] GetRandomArray(int Number,int minNum,int maxNum)
 {
  int j;
  int[] b=new int[Number];
  Random r=new Random();
  for(j=0;j<Number;j++)
  {
   int i=r.Next(minNum,maxNum+1);
   int num=0;
   for(int k=0;k<j;k++)
   {
    if(b[k]==i)
    {
     num=num+1;
    }
   }
   if(num==0 )
   {
    b[j]=i;
   }
   else
   {
    j=j-1;
   }
  }
  return b;
 }


------解决方案--------------------
Random random = new Random(DateTime.Now.Millisecond);  


或者


protected void Page_Load(object sender, EventArgs e)  
       {  

           Random rs = new Random();  

           int aaa = rs.Next(1,100001);  
       }

------解决方案--------------------
  int codelength = 6;


               string NumStr = null;
               int RadNum = r.Next(999999);
               if (RadNum.ToString().Length != 6)
               {

                   for (int j = 1; j <= 6 - RadNum.ToString().Length; j++)
                   {
                       NumStr += "0";
                   }
                   NumStr += RadNum.ToString();
               }
               else
               {
                   NumStr = RadNum.ToString();
               }
               string RandomCode = NumStr;

这个应该可以