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Lesson 19.1 – Scroll to the bottom of a rich text box

When you play the game, you probably noticed the messages RichTextBox scrolls to the top after you add more messages to it. So, the player has to manually scroll to the bottom to see the latest message.

We want to make it easier for the player.

 

How to scroll to the bottom of a RichTextBox

Step 1: Add this new ScrollToBottomOfMessages() function to the code in the SuperAdventure.cs class:

private void ScrollToBottomOfMessages()
{
    rtbMessages.SelectionStart = rtbMessages.Text.Length;
    rtbMessages.ScrollToCaret();
}

 

Step 2: After you add more to rtbMessages.Text, call the ScrollToBottomOfMessages() method.

 

That’s it.

 

Source code for this lesson

Source code on GitHub

Source code on Dropbox

 

Next lesson: Lesson 19.2 – Use a calculated value for a property

Previous lesson: Lesson 18.1 – Future enhancements for the game

All lessons: Learn C# by Building a Simple RPG Index

10 Comments

  1. ZzM
    ZzM January 4, 2015

    Hello,
    I just double-clicked on the rtbMessages RichTextBox and it created the function:
    private void rtbMessages_TextChanged(object sender, EventArgs e)

    I added:
    rtbMessages.SelectionStart = rtbMessages.Text.Length;
    rtbMessages.ScrollToCaret();

    Now i don’t have to insert a function everytime it changes the text

    • Scott Lilly
      Scott Lilly January 6, 2015

      Cool. That’s one nice thing about programming – there’s always another way to do something.

    • Jack
      Jack August 6, 2021

      But not being a button, which follows the code inserted inside when clicked, when is this piece of code executed? Whenever we do a rtmMessages.text?

      • Scott Lilly
        Scott Lilly August 6, 2021

        Step 2 says you’ll have to add a call to the ScrollToBottomOfMessages() function after every place where you add more text to rtbMessages.Text. I didn’t put specific location in this lesson because several of the people who asked about this made changes to their version of the program.

        Search your solution (Ctrl-Shift-F) for “rtbMessages.Text” and make sure every function where you add to it, you also call ScrollToBottomOfMessages().

  2. Senpai
    Senpai August 10, 2015

    Hey Scott,

    great tutorial so far, helped me a lot understanding the basics of C#.

    Just want to let you know that next and previous lesson are mixed up :p

    Thanks again.

    Have a nice day!

    • Scott Lilly
      Scott Lilly August 10, 2015

      Thanks for catching that and letting me know. You have a good day too!

  3. Conner
    Conner November 30, 2016

    When checking out this idea, I instead made a DisplayMessage function

    private void DisplayMessage(string msg)
    {
    rtbMessages.Text += msg;
    rtbMessages.SelectionStart = rtbMessages.Text.Length;
    rtbMessages.ScrollToCaret();
    }

    Is that a good idea for potential refactoring?

    I was thinking yes due to how you could constantly change where the messages were displayed

    • Scott Lilly
      Scott Lilly December 1, 2016

      Yes! You found an excellent opportunity for refactoring. When you do something in multiple places, it’s almost always better to call a common function.

    • Scott Lilly
      Scott Lilly August 9, 2021

      Hi,

      I replied to your previous comment. I am working during the day, so I cannot do a live share.

      Can you upload your solution (including the directories under it, and all the files in those directories) to GitHub, Dropbox, or some other file-sharing location so I can look at it?

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