WPF Richtextbox how to select text in programmatically

Question

I want to select text in richtextbox from  position and length in WPF.
for example : In richtextbox  in text like : I am testing this thing.
and  My startposition is =5; and lenght =3;
then richtextbox selection highlight  like this: I am tes ting this thing.

Rajanikant Hawaldar · Accepted Answer

Below example may help you RichTextBox   x:Name = "rtb"   x:FieldModifier = "private" >         FlowDocument >             Paragraph >                 Run > This is some text. Run >             Paragraph >         FlowDocument >    RichTextBox >    TextPointer text = rtb.Document.ContentStart;   while  (text.GetPointerContext(LogicalDirection.Forward) != TextPointerContext.Text)   {       text = text.GetNextContextPosition(LogicalDirection.Forward);   }   TextPointer startPos = text.GetPositionAtOffset(5);   TextPointer endPos = text.GetPositionAtOffset(7);   var textRange =  new  TextRange(startPos, endPos);   textRange.ApplyPropertyValue(TextElement.FontWeightProperty, FontWeights.Bold);

Kaushik Bhatt · Answer

Yes,Rajanikant Hawaldar.sorry to forget mention.Using MVVM pattern.I have also one issue to pass Grid from view to viewmodel with commandparamater. if you have solution for this,then please mention here, it would great help

Rajanikant Hawaldar · Answer

are you using any architectural pattern for you project, it seems your using mvvm, but you haven't said this before

Kaushik Bhatt · Answer

Thank you for all replies. I have done with like passing Richtextbox to Viewmodel via parameter and using textrange to highlight.

Anant Vernekar · Answer

Check out this solution
https://stackoverflow.com/questions/3707120/how-to-select-text-from-the-richtextbox-and-then-color-it

Pranam Bhat · Answer

This has the answer for your requirement: https://stackoverflow.com/questions/29316449/highlighting-keywords-in-a-richtextbox-in-wpf