How do I change font family of RichTextBox without modifying previous text?

Question

When I use formatting functions (i-e bold, italic, underline, font size, font color), then the the whole document is formatted including the new text entered. But I want to use these functionalities only to format new text that is going to be entered and the selected text.

How can I do this?

Answer 1

The problem can be resolve by using this code:

System.Drawing.Font currentFont = txtPAD.SelectionFont;

System.Drawing.FontStyle newFontStyle;

newFontStyle = txtPAD.SelectionFont.Style ^ FontStyle.Italic;

txtPAD.SelectionFont = new Font(currentFont.FontFamily, currentFont.Size, newFontStyle);