How to make a keyboard scrollable readonly WPF TextBox?

Question

It seems such a simple thing to do: use a TextBox to display some output and allow the user to cut and paste from it, scroll it but not edit it.

BUT: if a TextBox is readonly, then it loses most of its keyboard behaviour. You can click on it and select text using the invisible cursor, but it will not scroll or navigate.

I have this (terrible) solution.

<TextBox Focusable="True"
     VerticalScrollBarVisibility="Auto"
     HorizontalScrollBarVisibility="Auto"
     FontFamily="Consolas" FontSize="10pt"
     Foreground="{Binding Path=OutputTextColour}" 
     Text="{Binding Path=OutputText}"
     Background="White" PreviewKeyDown="TextBox_PreviewKeyDown" />

And a handler to throw away any attempts to edit:

   private void TextBox_PreviewKeyDown(object sender, KeyEventArgs e) {
  // the IsReadOnly flag on the control doesn't let the navigation keys work! WPF BUG?
  if (!(e.Key == Key.Down || e.Key == Key.Up || e.Key == Key.Left || e.Key == Key.Right 
     || e.Key == Key.Home || e.Key == Key.End || e.Key == Key.PageDown || e.Key == Key.PageUp 
     || e.Key == Key.Tab || e.Key == Key.Escape))
    e.Handled = true;
}

I have also tried a readonly TextBox inside a ScrollViewer, but it seems the TextBox, even when readonly, still swallows the navigation keystrokes and the ScrollView never sees them. If the ScrollViewer gets the focus then scrolling works and cut/copy/paste do not!

Yes, I could probably get all that to work by some fancy footwork with PreviewKeyDown, but really I just want a TextBox that plays nice!

For your current solution, what about when I want to hold down shift and select with the arrow keys, or Ctrl to select whole words? — Mathemats, Jan 25 '16 at 01:30
What keyboard behavior is missing? I can shift and ctrl-select text...I can use arrow keys and scroll with mouse selection — Bubba, Jan 25 '16 at 01:50
@Bubba: PgUp, PgDn, Home, End, Ctrl+Home, Ctrl+End lose their scrolling behaviour. — david.pfx, Jan 25 '16 at 05:13
@Mathemats: they work OK. Arrow keys are not marked as handled, so get passed through. — david.pfx, Jan 25 '16 at 05:14
I might be missing something, but your if statement reads if the key pressed is _not_ (left, up, etc) then handle it. Wouldn't you want to handle these key presses? Also, throw some braces around the body of the if... — Mathemats, Jan 25 '16 at 05:20
@Mathemats: if the key is not left, up etc then mark it handled so it doesn't get passed through. Only allow TextBox to see these chars. [And I NEVER write unnecessary braces -- you shouldn't either.] — david.pfx, Jan 25 '16 at 13:49

score 11 · Accepted Answer · edited May 23 '17 at 11:46

11

The answer is to set

IsReadOnlyCaretVisible="True"

as described here:

Readonly textbox for WPF with visible cursor (.NET 3.5)

Works beautifully!

edited May 23 '17 at 11:46

Community

1
1

answered Jul 29 '16 at 02:32

Jim Foye

1,918
1
13
15

thanks! That sounds like the answer. I can't check it out right now, but hopefully real soon now... – david.pfx Aug 07 '16 at 00:12
This worked for me - looks like the correct answer @david.pfx – GilesDMiddleton Apr 10 '17 at 10:17
This made the Page Up and Page Down button page the document but not the Cursor keys. Still an easy improvement over what I had before. – Christopher Painter Sep 10 '18 at 01:42

How to make a keyboard scrollable readonly WPF TextBox?

1 Answers1