Create Random number in .Net

You guys can create random number using below code up to 6 digit if u want to more than change in for loop.

public string CreateRandomCode()
{
string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
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(36);
if (temp != -1 && temp == t)
{
return CreateRandomCode(codeCount);
}
temp = t;
randomCode += allCharArray[t];
}
return randomCode;
}

Thanks & Regards
Jignesh Patel