title: i want to generate alfa numeric otp in asp.net c#
body: <pre><code>public void generate()
  {
      string alphabets = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
      string small_alphabets = "abcdefghijklmnopqrstuvwxyz";
      string numbers = "1234567890";
      string characters = numbers;
      characters += alphabets + small_alphabets + numbers;
  
      int length =6;
      string opt = string.Empty;
      for (int i = 0; i &lt; length; i++)
      {
          string character = string.Empty;
          do
          {
              int index = new Random().Next(0, characters.Length);
              character = characters.ToCharArray()[index].ToString();
          } while (otp.IndexOf(character) != -1);
          otp += character;
      }
      string str= otp;
  }
  </code></pre>
  
  <p>This is my code, which is not working for me.
  I want to try small alphabet, capital alphabet and 0 to 9 number combination.</p>