wpf textblock - set background color behind text only?

Question

when I set the background color on a textblock, it colors the fill rectangle of the textblock. If I have a multi-line textblock, in which the lines are normally unequal length, this shows empty spaces past the end of the shorter lines. This is fine, but is there a way I could set background color only behind the text lines themselves so this empty space is not created?

Answer 1

I'm not at a Windows machine so can't test this myself. The first thing I would try would be to style the Run class rather than TextBlock :

<Style TargetType="Run">
    <Setter Property="Background" Value="Blue"/>
</Style>

...

<TextBlock TextWrapping="Wrap">
    Lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum
</TextBlock>

I would do this on the assumption that TextBlock creates multiple Run instances when it has to wrap lines.

Answer 2

I think the easiest way is to put the TextBlock inside a border with BorderThickness=0 and set the background of the border. The border will expand with your textblock but won't take up extra space.