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function RandomPass ([int]$PasswordLength) {
  if ($PasswordLength -eq 0) {$PasswordLength = 16}
  $RandomPass = $null
  for ($a=1; $a -le $PasswordLength; $a++) {
    switch ($a) {
      8 {$b = [string][char](Get-Random -Minimum 33 -Maximum 48)} #Sonderzeichen
      4 {$b = [string][char](Get-Random -Minimum 48 -Maximum 58)} #Zahlen
      2 {$b = [string][char](Get-Random -Minimum 65 -Maximum 91)} #Großbuchstaben
      6 {$b = [string][char](Get-Random -Minimum 97 -Maximum 123)} #Kleinbuchstaben
      default {$b = [string][char](Get-Random -Minimum 33 -Maximum 127)} #alle
    }
    $RandomPass += $b
  }
  return $RandomPass
}					

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    static string RandomPass(int length)
    {
        string password = String.Empty;

        string special = "!\"#$%&'()*+,-./";
        string number = "0123456789";
        string upperCase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        string lowerCase = "abcdefghijklmnopqrstuvwxyz";

        char[] specials = special.ToCharArray();
        char[] numbers = number.ToCharArray();
        char[] upperCases = upperCase.ToCharArray();
        char[] lowerCases = lowerCase.ToCharArray();
        char[] all = (special + number + upperCase + lowerCase).ToCharArray();

        Random rnd = new Random();
        for (int i = 1; i < length; i++)
        {
            switch (i)
            {
                case 6:
                    password += specials[rnd.Next(0, specials.Length - 1)].ToString();
                    break;
                case 3:
                    password += numbers[rnd.Next(0, numbers.Length - 1)].ToString();
                    break;
                case 5:
                    password += upperCases[rnd.Next(0, upperCases.Length - 1)].ToString();
                    break;
                case 9:
                    password += lowerCases[rnd.Next(0, lowerCases.Length - 1)].ToString();
                    break;
                default:
                    password += all[rnd.Next(0, all.Length - 1)].ToString();
                    break;
            }
        }
        return password;
    }					

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char b = (char)57;
string s = b.ToString(); // liefert "9";					

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string number = "0123456789";
password += number[rnd.Next(0, number.Length)];					

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            string password = "";
            Random rnd = new Random();

            while(password.Length < length)
                switch (rnd.Next(0,3))
                {
                    case 0:
                        password += (char)rnd.Next(48,58);
                        break;
                    case 1:
                        password += (char)rnd.Next(33, 47);
                        break;
                    case 2:
                        password += (char)rnd.Next(97, 123);
                        break;
                    case 3:
                        password += (char)rnd.Next(65, 91);
                        break;
                }