为什么它在消息框而不是文本上显示问号

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://teamxor.net/vb/tx48/"+ page);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
StreamReader sr = new StreamReader(response.GetResponseStream());
string result = sr.ReadToEnd();
Regex r = new Regex("<div>.*?</div>");
MatchCollection mr = r.Matches(result);
foreach (Match m in mr)
{
MessageBox.Show(m.Value, "Test", MessageBoxButtons.OK, MessageBoxIcon.Information, MessageBoxDefaultButton.Button1, MessageBoxOptions.RtlReading);
}
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