[C#] 產生亂數

產生數字與英文大小寫所產生的字串

//Generate random strings
private string generateRandomString(int length)
{
string ranStr = "";
Random ran = new Random();
for (int i = 0; i < length; ++i)
{
switch (ran.Next(0, 3))
{
case 0:
ranStr += (char)ran.Next(65, 91); //A~Z
break;
case 1:
ranStr += (char)ran.Next(97, 122); //a~z
break;
case 2:
ranStr +=ran.Next(0,10); //0~9
break;
}
}
return ranStr;
}