Display line numbers in RichEditBox UWP

Question

I would like to know if it is possible to show the line numbers (in a separate column) of a RichEditBox in UWP C#, or if there are other ways to get it. I'm looking for a solution to this problem... And it seems odd to me that there is no documentation about it: i need only a simple text editor. There are a lot of applications for Windows 10 that implement it and I refuse to think that it is not possible.

This is just an example from CodeWriter, a code editor application. Any idea?

Answer 1

I achieve a "result" thinking about a list and the RichEditBox. Now, the solution isn't good, after about 50 lines typing it's laggy as hell, but at least I tried, 'cos the question is important also for me.

So, I designed a ListView and RichEditBox in a Grid with two columns

<ScrollViewer>
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"></ColumnDefinition>
            <ColumnDefinition></ColumnDefinition>
        </Grid.ColumnDefinitions>

        <ListView Grid.Column="0" Name="LineNumbers" ScrollViewer.VerticalScrollMode="Disabled" ScrollViewer.VerticalScrollBarVisibility="Disabled"></ListView>
        <RichEditBox Grid.Column="1" x:Name="RebText" TextChanged="RebText_TextChanged" ScrollViewer.VerticalScrollMode="Disabled" ScrollViewer.VerticalScrollBarVisibility="Disabled"></RichEditBox>
    </Grid>
</ScrollViewer>

At the code behind I added this one:

private void RebText_TextChanged(object sender, RoutedEventArgs e)
{
    //Clear line numbers
    LineNumbers.Items.Clear();
    int i = 1;

    //Get all the thext
    ITextRange text = RebText.Document.GetRange(0, TextConstants.MaxUnitCount);
    string s = text.Text;

    if (s != "\r")
    {
        //Replace return char with some char that will be never used (I hope...)
        string[] tmp = s.Replace("\r", "§").Split('§');
        foreach (string st in tmp)
        {
            //String, adding new line
            if (st != "")
            {
                LineNumbers.Items.Add(i++);
            }
            //No string, empty space
            else
            {
                LineNumbers.Items.Add("");
            }                      
        }
    }
}

I think the .clear() method and readding all the lines every time is n't a good practice. But if you need a quick solution on max 50 lines, this MAYBE is the way.