IEnumerable.Except to display differences in textbox c sharp

Question

I am new to C # and I am getting stuck on using IEnumerable.Except. What I am trying to do is get the difference of 2 sequences of 100 random dice rolls using 2 die. I have my die rolls and totals good to go.

My differences are not showing in my txtDifference textbox at all. I am not sure if I have it placed in the correct spot or if it isn't written correctly. The code itself has no errors and I am not sure how to fix it. Here is my code, any help is greatly appreciated!!

 private void btnRoll_Click(object sender, EventArgs e)
 {
        // create random  and lists        
        randomizer = new Random();
        List<int> numbers = new List<int>();
        List<int> secondNumbers = new List<int>();

        // for loop for 1st sequence 
        for (i = 1; i < 100; i++)
        {
                string mssg = string.Empty;
                die1 = randomizer.Next(1, 7);
                die2 = randomizer.Next(1, 7);
                dieRoll1.Text = die1.ToString();
                dieRoll2.Text = die2.ToString();
                rollValue = die1 + die2;

                // add to collection.
                numbers.Add(i);

                // display results
                txtResults.Text += string.Concat(dieRoll1.Text, "               ", dieRoll2.Text, "               ", rollValue, "              ", Environment.NewLine);
        }

        //loop for second sequence. 
        for (i = 1; i < 100; i++)
        {
            string mssg = string.Empty;
            die1 = randomizer.Next(1, 7);
            die2 = randomizer.Next(1, 7);
            dieRoll1.Text = die1.ToString();
            dieRoll2.Text = die2.ToString();
            rollValue = die1 + die2;
            
            //add to collection. 
            secondNumbers.Add(i);

            //display results in second text box
            txtResults2.Text += string.Concat(dieRoll1.Text, "              ", dieRoll2.Text, "              ", rollValue, "              ", Environment.NewLine);
        }

        // IEnumerable for comparison between the two sequences 
        IEnumerable<int> onlyInFirstSet = numbers.Except(secondNumbers);

        //foreach to display the differences between the sequences 
        foreach (int number in onlyInFirstSet)
            txtDifference.Text = number.ToString(); 
    }

Answer 1

Both loops iterate from 1 to 100. Then, in both cases, you're adding the value of i to the lists... which means both lists end up with the values 1 to 100 in them.

numbers.Add(i);
secondNumbers.Add(i);

So the following line of code always results in an empty list. It removes the second collection of numbers 1 to 100 from the first collection of numbers 1 to 100.

IEnumerable<int> onlyInFirstSet = numbers.Except(secondNumbers);

Instead, add the rollValue value to your list, not the variable your foreach loop is iterating over:

rollValue = die1 + die2;

//add to collection.
numbers.Add(rollValue);

Same goes for your second loop and collection:

rollValue = die1 + die2;

//add to collection. 
secondNumbers.Add(rollValue);