利用WebClient和正则提取网页QQ邮箱

string strUrl = txtUrl.Text.Trim() + "?pn=";
int iPageSize = Convert.ToInt32(txtPageSize.Text.Trim());
WebClient wc = new WebClient();
StringBuilder sb = new StringBuilder();
string html = "";
wc.Encoding = Encoding.Default;

for (int i = 1; i <= iPageSize; i++)
{
    strUrl += i;
    html = wc.DownloadString(strUrl);
    MatchCollection mc = Regex.Matches(html, @"[1-9]\d{4,11}@(qq|QQ).com");
    foreach (Match m in mc)
    {
        sb.AppendLine(m.Value + ";");
    }
}

File.AppendAllText(@"h:\1.txt", sb.ToString(), Encoding.Default);