输入文本框，当点击enter时，做进一步处理！

//登录用户文本框敲回车键
private void txtCode_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
txtPwd.Focus();
}
}
//登录密码文本框敲回车键
private void txtPwd_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
picLogin_Click(sender,e);
}
}