private void btnlogin_Click(object sender, EventArgs e)
{
int state = qq.loginQQ(txtpwd.Text.Trim(), txtVerify.Text.Trim(), out string nick);
switch (state)
{
case 1:
MessageBox.Show("登录成功！欢迎你：" + nick, "恭喜！");
break;
case 2:
MessageBox.Show("账号或密码错误！", "提示：");
txtuser_Leave(null, null);
break;
case 3:
MessageBox.Show("验证码错误！", "提示：");
pic_verify.Image = qq.getCapture();
break;
default:
MessageBox.Show("出现致命错误！导致无法正常访问！", "提示：");
break;
}
}