private void AddUserBtn_Click(object sender, EventArgs e)
{
if (AddUserTxt.Text == "")
{
return;
}
_user = new User();
_user.SetName(AddUserTxt.Text);
_user.SetOptimTemp(Int32.Parse(OptimTempTxt.Text));
AddUserTxt.Text = "";
_broker.AddUser(_user);
UpdateListControl();
UpdateDropDownList();
UserDrpDwn.SelectedItem.Text = _user.Name;
}