如何在 RichTextBox 中附加 RTF 文本，Win C#

我在 Win C# 中有一个 RichTextBox，我想在 RichTextBox 中附加一些具有粗体效果的新文本。那么我该怎么做呢。

I tried

string str = richTextBox.Rtf;

//my logic
str+= @"\rtf1\ansi Adding Some \b Text\b0.}";
//

正在追加

richTextbox.AppendText(str);

但它没有显示正确的。

我之前的输出

This is First Word.

我想要输出像

This is First单词。添加一些Text.

那么我该怎么做呢？

以下函数引用 RichTextBox 以及一些格式化参数。该函数已记录：

/// <summary>
/// Append formatted text to a Rich Text Box control 
/// </summary>
/// <param name="rtb">Rich Text Box to which horizontal bar is to be added</param>
/// <param name="text">Text to be appended to Rich Text Box</param>
/// <param name="textColour">Colour of text to be appended</param>
/// <param name="isBold">Flag indicating whether appended text is bold</param>
/// <param name="alignment">Horizontal alignment of appended text</param>
private void AppendFormattedText(RichTextBox rtb, string text, Color textColour, Boolean isBold, HorizontalAlignment alignment)
{
    int start = rtb.TextLength;
    rtb.AppendText(text);
    int end = rtb.TextLength; // now longer by length of appended text

    // Select text that was appended
    rtb.Select(start, end - start);

    #region Apply Formatting
    rtb.SelectionColor = textColour;
    rtb.SelectionAlignment = alignment;
    rtb.SelectionFont = new Font(
         rtb.SelectionFont.FontFamily,
         rtb.SelectionFont.Size,
         (isBold ? FontStyle.Bold : FontStyle.Regular));
    #endregion

    // Unselect text
    rtb.SelectionLength = 0;
}

下面的代码添加了原文：

This is First Word.

// This creates the original text
AppendFormattedText(richTextBox, "This is ", Color.Black, false, HorizontalAlignment.Left);
AppendFormattedText(richTextBox, "First", Color.Black, true, HorizontalAlignment.Left);
AppendFormattedText(richTextBox, " Word.", Color.Black, false, HorizontalAlignment.Left);

...然后在末尾附加一个句子，这样富文本框的内容就是所需的：

This is First单词。添加一些Text.

// This appends additional text
AppendFormattedText(richTextBox, " Adding Some ", Color.Black, false, HorizontalAlignment.Left);
AppendFormattedText(richTextBox, "Text", Color.Black, true, HorizontalAlignment.Left);
AppendFormattedText(richTextBox, ".", Color.Black, false, HorizontalAlignment.Left);

除了问题中要求的参数之外，还有其他参数（例如颜色），但这些参数构成了所有格式化操作的基础，可以使用选择-格式-取消选择格式化方法来完成，而不是手动编辑RTF 代码。