RichTextBox 粗体文本

Question

I am filling a richtextbox with information gathered from Textboxes. I need that the input from the user gets Bold in the Richtextbox. I have tried different answers in SO, but or either I am doing something wrong or I couldn't find the right answer to this.

I've tried RTF and appendtext:

rtbGeneratedText.Text += @"In answer to your request regarding " + 
    rtbSpecialRequest.Text +
    " for your booking " +
    bookingNumberTxt.Text +
    " the hotel has informed us that unfortunately it is not possible." + "\r\n" + 
    "Please let us know if this negative answer will affect your reservation in any way.";

Answer 1

Here is how you can Bold a portion of the sentence (a few words):

string target = "the hotel has informed us that unfortunately it is not possible";
RichTextBox1.SelectionStart = RichTextBox1.Text.IndexOf(target);
RichTextBox1.SelectionLength = target.Length;
RichTextBox1.SelectionFont = new Font(RichTextBox1.Font, FontStyle.Bold);

Or if you want to Bold all the text:

RichTextBox1.SelectionStart = 0;
RichTextBox1.SelectionLength = RichTextBox1.Length;
RichTextBox1.SelectionFont = new Font(RichTextBox1.Font, FontStyle.Bold);