I have a TextBlock with the following setting:
TextWrapping=\"Wrap\"
Can I determine the maximum number of lines?
for exam
In UWP Apps you don't need this and can use the TextBlock property MaxLines (see MSDN)
If you have a specific LineHeight you can calculate the maximum height for the TextBlock.
TextBlock with maximum 3 lines
<TextBlock
Width="300"
TextWrapping="Wrap"
TextTrimming="WordEllipsis"
FontSize="24"
LineStackingStrategy="BlockLineHeight"
LineHeight="28"
MaxHeight="84">YOUR TEXT</TextBlock>
This is all that you need to get your requirement working.
Just create a new control in C#/VB.NET that extends TextBlock and give it a new DependencyProperty int MaxLines.
Then override the OnApplyTemplate() method and set the MaxHeight based on the LineHeight * MaxLines.
That's just a basic explanation on how you could solve this problem!