生成随机数的两个方法

private static char[] constant ={
'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'
};
public static string GenerateRandom(int Length)
{
System.Text.StringBuilder newRandom = new System.Text.StringBuilder(36);
Random rd = new Random();
for (int i = 0; i < Length; i++)
{
newRandom.Append(constant[rd.Next(36)]);
}
return newRandom.ToString();
}

protected static string GetMixPwd(int num)//生成混合随机数
{
string a = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
StringBuilder sb = new StringBuilder();
for (int i = 0; i < num; i++)
{
sb.Append(a[new Random(Guid.NewGuid().GetHashCode()).Next(0, a.Length - 1)]);
}

return sb.ToString();
}