If you need a LineBreak in a TextBlock you have some options depending on your scenario.
In XAML
If you enter the text in XAML you can add a LineBreak tag to your text.
<TextBlock> <Run>Lorem Ipsum has been the industry's standard</Run> <LineBreak /> <Run>It has survived not only five centuries.</Run> </TextBlock>
In C#
If you enter the text in C# you can add \n to your text to add a new line.
TextBlock1.Text = "Lorem Ipsum has\nIt has survived not only.";
where TextBlock1 is my TextBlock.
In Binding
If you get your text from a database and use Binding to add text to your TextBlock neither of the two solutions above will work. As long as it is text being bound to the Text property of the TextBlock, then all you need to do is embed CR/LF character codes into your data.
by xamlgeek