Eto: [WPF] RichTextArea Selection not working correctly

Created on 4 Oct 2018 · 7Comments · Source: picoe/Eto

Expected Behavior

Text correctly selected according to defined range.

Actual Behavior

There is a misplacement of 5 characters to the right.

Steps to Reproduce the Problem

Create a RichTextArea control
Input some text
Define a selection to set its color

Code that Demonstrates the Problem

rtfcontrol.Appen(initialtext, true);
rtfcontrol.Append(sometext, true);
rtfcontrol.Selection = new Range<int>(rtfcontrol.Text.Length - sometext.Length, rtfcontrol.Text.Length -1);
rtfcontrol.SelectionForeground = Colors.Blue;
rtfcontrol.Append("\n", true);
rtfcontrol.Selection = new Range<int>(rtfcontrol.Text.Length);

Specifications

Version: 2.5.0-ci-10013
Platform(s): WPF
Operating System(s): Windows 10

WPF:

wpf

GTK2 (Linux):

gtk2_linux

Xamarin.Mac:

xamarin mac

Source

DanWBR

Most helpful comment

@DanWBR, ah yes that won't work the way you have it unfortunately - WPF adds a newline at the end of the Text property (regardless if your text has it or not). I have not found a way around that at this point, but it is a separate issue from this one.

What I'd recommend is to keep the current position in a variable and increment it after appending text. Accessing the Text property each time just to get the length will slow down as the text gets larger.

cwensley on 5 Dec 2018

👍2

All 7 comments

On Windows, the line ending characters are somehow not counted to the indices for selections. I currently use the following code as work-around:

private void Write(string message, Color c)
        {
            Append(message + Environment.NewLine, true);

            int idx = -1, last = -1;
            if (Environment.OSVersion.Platform == PlatformID.Unix)
            {
                idx = Text.LastIndexOf(message);
                last = Text.Length;
            }
            else
            {
                var lines = string.Join("", Text.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries));
                idx = lines.LastIndexOf(message);
                last = lines.Length;
            }

            if (idx == -1)
                return;

            Selection = new Range<int>(idx, idx + message.Length);
            SelectionForeground = c;
            Selection = new Range<int>(last, last);
        }

But this is definitely a bug...

ManuelHu on 13 Oct 2018

Yeah I've used the same hack as @ManuelHu before, it isn't pretty. I'm not sure yet how to effectively address this without being dog slow with large text.

Thanks for reporting the issue!

cwensley on 16 Oct 2018

👍1

Hey @DanWBR,

This should be fixed in latest develop branch. Could you give it a go? On all platforms newlines are now treated as a single \n character.

cwensley on 15 Nov 2018

Hi @cwensley, there's still one character left to fix:

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