The following code return a random number lower than 1000
  
    int num = random.Next(1000);  

The following code returns a random number between the min and the max range.

    // Instantiate random number generator.  
    private readonly Random _random = new Random();  
      
    // Generates a random number within a range.      
    public int RandomNumber(int min, int max)  
    {  
      return _random.Next(min, max);  
    }