c# - Changing a string inside of an if statement isn't working

Alright so I have this in game command so here it is

        internal class GambleCommand : Command
{
    public GambleCommand()
        : base("roll", 3)
    {
    }

    protected override bool Process(Player player, RealmTime time, string[] args)
    {
        try
        {
            if (args.Length == 1)
            {

                int num = int.Parse(args[0]);

                Random rnd = new Random();

                string pl = player.Name;

                string rand = rnd.Next(0, num).ToString();

                if (num < 0)
                {
                    rand = rnd.Next(num, 0).ToString();
                }

                    foreach (Client i in player.Manager.Clients.Values)
                    {
                        i.SendPacket(new TextPacket
                        {
                            BubbleTime = 0,
                            Stars = -1,
                            Name = pl,
                            Text = "rolled a " + rand + " out of " + num + "."
                        });
                    }
                }
            }

        catch
        {

            Random rnd = new Random();

            string pl = player.Name;

            string rand = rnd.Next(0, 100).ToString();

            foreach (Client i in player.Manager.Clients.Values)
            {
                i.SendPacket(new TextPacket
                {
                    BubbleTime = 0,
                    Stars = -1,
                    Name = pl,
                    Text = "rolled a " + rand
                });
            }
        }
        return true;
    }
}

Everything here works fine except for the part that says

                if (num < 0)
                {
                    rand = rnd.Next(num, 0).ToString();
                }

Basically what this should do is change places from (0, num) num being the maximum number to (num, 0) if the number you choose is a negative. As of right now when I put a negative it goes to default 0-100 which is the catch statement. Please help me asap! Thanks, Dante.