using System;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        for(int i = 0; i < 10; i++)

            Console.WriteLine(incidentId());

    }

    public static String incidentId()

    {

        StringBuilder randomString = new StringBuilder();

        Random random = new Random(Guid.NewGuid().GetHashCode());

        var possibleValues = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789";

        char ch;

​

        for (int i = 0; i < 6; i++)

        {

            var index = Convert.ToInt32(Math.Floor(possibleValues.Length * random.NextDouble()));

            ch = possibleValues[index];

            randomString.Append(ch);

        }

​

        return randomString.ToString(0, 3) + "-" + randomString.ToString(3, 3);

    }

}