Textblock失去了粗体文本

Question

I have a TextBlock

<TextBlock x:Name="TopTextBlock">
   Normals words followed by <Bold>Bold words</Bold>
</Textblock>

It displays the text bold.

However, if in my C# code I make any alterations to the string such as

TopTextBlock.Text += " word"

The text will no longer appear bold

Answer 1

Add string in TextBlock Inlines instead of setting Text DP :

TopTextBlock.Inlines.Add(" word");

Or in case want to add Bold text :

TopTextBlock.Inlines.Add(new Run(" word") { FontWeight = FontWeights.Bold });

Answer 2

The XAML implicitly sets the TextBlock's Inlines property, whereas in code behind you set the Text property. You might however add text to the Inlines collection like this:

TopTextBlock.Inlines.Add(new Run(" word"));

or shorter:

TopTextBlock.Inlines.Add(" word");