RichTextBox in WPF not resizing contents correctly

I need to display text with colors and formatting in a List. I'm using a ListBox with a RichTextControl to display the data. I also need the contents to size to the window, but the text does not need to wrap.

When I make this simple example the text appears vertical and doesn't change as I size the window. If I set the Width of the RichTextBox to a fixed size like 100 then it wo开发者_如何学Crks.

Any ideas?

<Window x:Class="WpfApplication19.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window1" Height="300" Width="300">
    <Grid>
        <ListBox HorizontalContentAlignment="Stretch">
            <ListBox.Items>
                <RichTextBox>
                    <FlowDocument>
                        <Paragraph>
                            <Run>this is a  test</Run>
                        </Paragraph>
                    </FlowDocument>
                </RichTextBox>
            </ListBox.Items>                
        </ListBox>
    </Grid>
</Window>

If there is a better option for displaying text were parts of the text are different colors please let me know.

If you don't need the list selection behaviour of the ListBox, then using a ItemsControl provides correct layout:

<Grid>
    <ItemsControl>
        <RichTextBox>
            <FlowDocument>
                <Paragraph >
                    <Run>this is a  test</Run>
                </Paragraph>
            </FlowDocument>
        </RichTextBox>
    </ItemsControl>
</Grid>

The but to get what you asked for, wrap RichTextBox in the Grid and then Bind to it's ActualWidth

<Grid>
    <ListBox HorizontalContentAlignment="Stretch">
        <ListBox.Items>
            <Grid>
                <RichTextBox Width="{Binding Path=ActualWidth, RelativeSource={RelativeSource AncestorType=Grid}}" >
                    <FlowDocument>
                        <Paragraph>
                            <Run>this is a  test</Run>
                        </Paragraph>
                    </FlowDocument>
                </RichTextBox>
            </Grid>
        </ListBox.Items>
    </ListBox>
</Grid>

This is an old question, but the issue can be resolved by setting ScrollViewer.HorizontalScrollBarVisibility="Disabled". This has to do with ListBox using a ScrollViewer internally and how it interacts with RichTextBox.

<Grid>
    <ListBox HorizontalContentAlignment="Stretch" ScrollViewer.HorizontalScrollBarVisibility="Disabled">
        <ListBox.Items>
            <RichTextBox>
                <FlowDocument>
                    <Paragraph>
                        <Run>this is a  test</Run>
                    </Paragraph>
                </FlowDocument>
            </RichTextBox>
        </ListBox.Items>
    </ListBox>
</Grid>