How do I Increase Fontsize for text in richtextbox

Question

How to set font size in each time i call a method.i want to use richtextbox.ApplyPropertyValue() method. I already tried

myrichtextbox.SetValue(TextElement.FontSizeProperty, fontSizedouble +10);

myrichtextbox.FontSize = (myrichtextbox.FontSize + 10);

Answer 1

For rich text box you need selection--

try this

TextSelection selectedText = myrichtextbox.Selection;

selectedText.ApplyPropertyValue(RichTextBox.FontSizeProperty, fontSizedouble +10);

For all text you can try this --

TextRange allText = new TextRange(MyRichTextBox.Document.ContentStart, MyRichTextBox.Document.ContentEnd);

allText.ApplyPropertyValue(RichTextBox.FontSizeProperty, fontSizedouble +10);

And to change size again and again you need to check size for text not richTextBox, do this --

TextRange allTextRange = new TextRange(MyRichTextBox.Document.ContentStart, MyRichTextBox.Document.ContentEnd);

var size = (double)allTextRange.GetPropertyValue(FontSizeProperty);

allTextRange.ApplyPropertyValue(RichTextBox.FontSizeProperty, size + 10);

Answer 2

从FlowDocument更改它。

this.Document.FontSize = this.Document.FontSize + 10;