在RichTextBox中控制水平滚动

Question

I have a RichTextBox that I'm spewing log information to, but the RichTextBox seems to want to horizontally scroll whenever text is appended that is too long to fit.

After searching extensively, and repeatedly failing with ScrollToCaret() , it would seem that this function controls the vertical scroll position, but not the horizontal. I have also attempted at using the API calls GetScrollRange() and SetScrollPos() , and while these do place the scrollbars in the right locations, they aren't controlling the actual location at which the RichTextBox is scrolled.

Answer 1

Could it be that there is no newline at the end of each log information in the log? use the System.Environment.Newline to append to the end of each line before putting it into the richtextbox. Take a look at this article on CodeProject which might help you and set you up in the right direction.

Hope this helps, Best regards, Tom.

Answer 2

This is a little messy, but it should work: When you do a ScrollToCaret and the horizontal scroll position changes, it fires an HScroll event. If the HScroll event occurs when you don't want it to, you can move the horizontal scroll bar back by 1. Move the selectionstart to 1 character after the previous crlf 2. Set the selectionstart to that location, and then 3. ScrollToCaret.

Answer 3

Easy Way to Jump To Start of Last Line Of ReadOnly RichTextBox

Salvete! Here is what I did. I was using a richtext box as a logging display, so it was constantly receiving new strings appended to the bottom of the text, and the strings were always longer than the richtext box was wide. I wanted to have the last line always showing, but at the start of the line instead of the end.

I added a TextChanged event handler (you get it in the properties panel of the richtext box). The vbcrlf ensures that the last line is always a blank line, and since there is no text in that line, the ScrollToCaret() will automatically be at the first character. Unless you have textwrap turned on, make sure to set your scrollbar properties to both so users can scroll to see what is at the other end of the lines.

Note that this solution only works for a read-only richtext box. If it isn't read-only and the user types into it, every character will end up on its own line! With readonly set to true, your program will still be able to change the text - just the user won't be able to, and the last-entered line will always be the one visible!

 Private Sub my_richtextbox_TextChanged( sender As System.Object,  e As System.EventArgs) Handles my_richtextbox.TextChanged
    With my_richtextbox
        .Text = .Text & vbcrlf
        .SelectionStart = .Text.Length
        .ScrollToCaret()
    End With
End sub