protected void Button1_Click(object sender, EventArgs e)
    {
        if (sigma.Count == 0)
        {
            Response.Write("<script>alert('你没文章怎么删啊????');</script>");
            return;
        }
        int wtdelid = sigma[DropDownList1.SelectedIndex].NID; //待删除文章ID
        int selid   = DropDownList1.SelectedIndex;            //当前选择id

        if (ArticleManager.DelArticleById(wtdelid))
        {
            //删除成功
            Response.Write("<script>alert('删除成功.');</script>");
            sigma.RemoveAt(selid);
            DropDownList1.Items.Clear();
            for (int i = 0; i < sigma.Count; ++i)
            {
                ListItem Item = new ListItem(sigma[i].NTitle, i.ToString());
                DropDownList1.Items.Add(Item);
            }
            if (DropDownList1.Items.Count > 0)//删除以后判断一下..是否DropDownList中还有文章列表呢
            {
                DropDownList1.SelectedIndex = 0;
                TextBox1.Text = sigma[0].NTitle;
                TextBox2.Text = sigma[0].NContent;
                TextBox3.Text = sigma[0].Aname;
            }
            else//你写了文章,又删干净了...一切初始化,世界安静了..0.0
            {
                Label1.Text   = "你还没有写文章呢,快去写几篇吧.";
                TextBox1.Text = "";
                TextBox2.Text = "";
                TextBox3.Text = "";
            }
        }
        else
        {
            //删除失败
            Response.Write("<script>alert('莫名其妙的删除出错= =????');</script>");
        }
    }