Rich Text Box - Bold | 易学教程

问题

I know there are loads of "how to bolden text" questions on here, but none of the answers are helping, I think it may be that the Rich Text Box is being created at runtime.

I'm making a chat client, so I have a rich text box split up in lines and the messages are as follows: {Name}: {Message} \r\n

I want to bolden the name, I have tried many code examples, but this is the closest I've got to it working:

int length = textBox.Text.Length;
textBox.Text += roomChatMessage.from + ": " + roomChatMessage.text + "\r\n";
textBox.Select(length, roomChatMessage.from.Length);
textBox.SelectionFont = new Font(textBox.Font, FontStyle.Bold);

The first message, it works perfectly fine, the name is in bold. But when I add a second message, everything turns bold even though the second time round I'm selecting the start index (Which is this example is 37) but everything just turns bold, all the past messages too!

Any idea to what may cause this? Thanks in advance!

回答1:

This line is a problem:

textBox.Text += roomChatMessage.from + ": " + roomChatMessage.text + "\r\n";

You are replacing the formatting and the text with this new version of a string, and is probably picking up the bold font from the last update.

Try using AppendText instead:

textBox.AppendText(roomChatMessage.from + ": " + roomChatMessage.text + "\r\n");

回答2:

 ObjRichTextBox.SelectionFont = new Font(ObjRichTextBox.Font, FontStyle.Bold);

 ObjRichTextBox.AppendText("BOLD TEXT APPEARS HERE");

 ObjRichTextBox.SelectionFont = new Font(ObjRichTextBox.Font, FontStyle.Regular);

 ObjRichTextBox.AppendText("REGULAR TEXT APPEARS HERE");

Hope this helps :)

回答3:

Here's some code I used one time :

var sb = new StringBuilder();
        sb.Append(@"{\rtf1\ansi");
        sb.Append(@"\b Name: \b0 ");
        sb.Append((txtFirstName.Text);
        sb.Append(@" \line ");
        sb.Append(@"\b DOB: \b0 ");
        sb.Append(txtDOBMonth.Text);
        sb.Append(@" \line ");
        sb.Append(@"\b ID Number: \b0 ");
        sb.Append(txtIdNumber.Text);
        sb.Append(@" \line \line ");
        sb.Append(@"}");

rtxtRequest.Rtf = sb.ToString();

if you append @"\rtf1\ansi" you can use \b and \b0 to declare bold within the string. And \line creates a new line. You can also do underline, etc. I found it easier to build the String like this than applying properties.

回答4:

In Visual Studio you can use this short code:

richTextBox1.Rtf = @"{\rtf1\ansi This is in \b bold\b0.}";

It will be:

This is in bold

回答5:

I feel it may be easier to use the RichTextBox.Rtf property when performing this kind of action, as mentioned here:

MSDN: Code: Formatting Characters in Bold in a RichTextBox Control (Visual C#)

Since as the contents of your text box grows, handling selection entities may end up becoming cumbersome.

来源：https://stackoverflow.com/questions/17284573/rich-text-box-bold

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richtextbox