C#生成随机验证码

private static string CreateCode(int count)
{
string code = "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[] keyCode = code.Split(',');
string validateCode = string.Empty;
Random rand = new Random();
do
{
validateCode = string.Empty;
for (int i = 0; i < count; i++)
{
string s = keyCode[rand.Next(0, 35)];
validateCode += s;
}
}
while ((validateCode.Contains("0") && validateCode.Contains("O")));
return validateCode;
}