C#生成可自由选择随机字母数字的类型的函数

C#生成可自由选择随机字母数字的类型的函数。

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', '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 enum RandomType
{
All,
Number,
Uppercased,
Lowercased,
NumberAndUppercased,
NumberAndLowercased,
UppercasedAndLowercased,
}
public static string GenerateRandom(int Length,RandomType rt)
{
int initsize=0;
int beginsize = 0;
int endsize=0;
Boolean IsCross=false;
switch (rt)
{
case RandomType.All:
{
initsize = 62;
beginsize = 1;
endsize = 62;
//IsCross = false;
break;
}
case RandomType.Lowercased:
{
initsize = 26;
beginsize = 11;
endsize = 36;
//IsCross = false;
break;
}
case RandomType.Uppercased:
{
initsize = 26;
beginsize = 37;
endsize = 62;
// IsCross = false;
break;
}
case RandomType.Number:
{
initsize = 10;
beginsize = 1;
endsize = 10;
//IsCross = false;
break;
}
case RandomType.UppercasedAndLowercased:
{
initsize = 52;
beginsize = 11;
endsize = 62;
//IsCross = false;
break;
}
case RandomType.NumberAndLowercased:
{
initsize = 36;
beginsize = 1;
endsize = 36;
//IsCross = false;
break;
}
case RandomType.NumberAndUppercased:
{
IsCross = true;
break;
}
}
System.Text.StringBuilder newRandom = new System.Text.StringBuilder(initsize);
Random rd = new Random();
if (!IsCross)
{
for (int i = 0; i < Length; i++)
{
newRandom.Append(constant[rd.Next(beginsize, endsize)]);
}
}
else
{
for (int i = 0; i < Length; i++)
{
newRandom.Append(constant[rd.Next(1, 10)]);
newRandom.Append(constant[rd.Next(37, 62)]);
}
}
return newRandom.ToString();
}

使用：GenerateRandom(20,RandomType.NumberAndUppercased )