生成随机的颜色值

现在要随机生成一组RGB值,如:#FFFFFF
要点是随机生成6个字符,这6个字符从0-9,A-F中取.然后与#连接构成颜色值.

public static string CreateRandomColor()
  {
   string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F";
   string[] allCharArray = allChar.Split(',');
   string randomCode = "";
   int temp = -1;

   Random rand = new Random();
   for(int i = 0; i < 6; i++)
   {
    if(temp != -1)
    {
     rand = new Random(i*temp*((int)DateTime.Now.Ticks));
    }
    int t = rand.Next(15);
    if(temp == t)
    {
     return CreateRandomColor();
    }
    temp = t;
    randomCode += allCharArray[t];
   }
   return "#"+randomCode;
  }

 

调试:

正确，

循环10次

for(int i=0;i<=10;i++)
   {
    Console.WriteLine(CreateRandomColor());
   }

却重复了，根本没有达到随机的效果。怎么回事？

[STAThread]
        static void Main(string[] args)
        {
            //
            // TODO: 在此处添加代码以启动应用程序
            //
            string str1 = CreateRandomColor();
            string str2;
            for(int i=0;i<=10;i++)
            {
                str2 = CreateRandomColor();
                if(str2!=str1)
                {
                    Console.WriteLine(str2);
                    str2=str1;
                }
            }
            
    }
        public static string CreateRandomColor()
        {
            string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F";
            string[] allCharArray = allChar.Split(',');
            string randomCode = "";
            int temp = -1;

            Random rand = new Random();
            for(int i = 0; i < 6; i++)
            {
                if(temp != -1)
                {
                    rand = new Random(i*temp*((int)DateTime.Now.Ticks));
                }
                int t = rand.Next(15);
                if(temp == t)
                {
                    return CreateRandomColor();
                }
                temp = t;
                randomCode += allCharArray[t];
            }
            return "#"+randomCode;
        }