如何在C＃中将RichTextBox转换为大写？

Question

I try:

private void button1_Click(object sender, EventArgs e)
{
    richTextBox1.SelectAll();
    string[] textArray = richTextBox1.SelectedText.Split(new char[] { '\n', '\t' });
    foreach (string strText in textArray)
    {
        if (!string.IsNullOrEmpty(strText) && strText != "rtf")
        richTextBox1.Rtf = richTextBox1.Rtf.Replace(strText, strText.ToUpper());
    }
}

and, in my windows form:

when i click button 1:

It do not work with "tôi tên là" Please help me. Thank!

Answer 1

You are probably not utilising culture info

    "tôi tên là".ToUpper(CultureInfo.GetCultureInfo("fr-FR"));
  // put your culture instead of fr-FR inside