Why is text not bold in RichTextBox?

Question

C++ / C#

public static void AddLineAndBlob(ref RichTextBox textBox, KeyValuePair<string, double[]> item, string[] blob)
{
    textBox.Text += item.Key + " ";
    int selectIndex = textBox.Text.Length;
    for (int i = 0; i < item.Value.Length; i++)
    {
        if (Array.IndexOf(blob, item.Value[i].ToString()) == -1)
        {
            textBox.Text += item.Value[i].ToString() + " ";
            selectIndex += textBox.Text.Length;
         }
         else
         {
              textBox.Text += item.Value[i].ToString() + " ";
              textBox.Select(selectIndex, item.Value[i].ToString().Length);
              textBox.SelectionFont = new Font(textBox.Font, FontStyle.Bold);
              selectIndex += textBox.Text.Length;
          }
    }
    textBox.Text += "\n";
}

Here is my method. All conditions pass correctly, no exceptions. But there is still no bold text. What is the problem?

Answer 1

after changing .Text you can forget about formatting
. I suggest checking this statement.