富文本框中的粗体或普通文本

Question

I'm doing a project and part of is to.

if the line number of the rich text box is odd, I want the text to make bold, else the line number is even number I want write text normal. How can i do this?

Output must be like this:

line number 1 (odd)

line number 2 (even)

line number 3 (odd)

line number 4 (even)

My English is not so good, sorry.

Answer 1

Use RichTextBox.SelectionFont

int SelectionStart = richtextbox1.SelectionStart; //Start of bold text
int SelectionLenght = richtextbox1.SelectionLength; //End of bold text

// Set font of selected text
// You can use FontStyle.Bold | FontStyle.Italic to apply more than one style
richtextbox1.SelectionFont = new Font(richtextbox1.Font, FontStyle.Bold);

// Set cursor after selected text
richtextbox1.SelectionStart = richtextbox1.SelectionStart + richtextbox1.SelectionLength;
richtextbox1.SelectionLength = 0;
// Set font immediately after selection
richtextbox1.SelectionFont = richtextbox1.Font;

// Reselect previous text
richtexbox1.Select(SelectionStart, SelectionLength);