private void button3_Click(object sender, EventArgs e)         {             this.textBox1.Text=@"http://localhost/Default.aspx";       //认证的网址或路径             this.textBox2.Text="spsservice";                             //账户名             this.textBox3.Text = "Zd$1234";                              //密码             MSXML2.XMLHTTP http = new MSXML2.XMLHTTP();             http.open("post", this.textBox1.Text, false, this.textBox2.Text, this.textBox3.Text);             http.send("");             switch (http.status)             {                 case 200:                     {                         MessageBox.Show("登录成功！");                         break;                     }                 case 401:                     {                         MessageBox.Show("用户名和密码错误");                         break;                     }                 default:                     {                         MessageBox.Show("连接失败，请重试");                         break;                     }