private void OK_Click(object sender, EventArgs e)
{
//实例化创建BLL层的工厂
FactoryBLL factBll = new FactoryBLL();
//调用查询余额的业务接口和实例化BLL层的工厂，实例化BLL层具体的类
QueryCashIBLL querIBLL = (QueryCashIBLL)factBll.CreateUser("QueryCashBLL");
//调用查询余额方法，获取当前用户余额
string strMsg = querIBLL.SelectCash(txtCardno.Text, this);
txtCash.Text = strMsg;//显示余额
}
private void QueryCash_Load(object sender, EventArgs e)
{
//实例化创建BLL层的工厂
FactoryBLL factBll = new FactoryBLL();
//调用查询余额的业务接口和实例化BLL层的工厂，实例化BLL层具体的类
QueryCashIBLL querIBLL = (QueryCashIBLL)factBll.CreateUser("QueryCashBLL");
txtCardno.Text = UserLevel.UserIdall.ToString();//给卡号赋值，把当前用户的全局变量赋值给卡号。
//调用查询余额方法，获取当前用户余额
string strMsg = querIBLL.SelectCash(txtCardno.Text, this);
txtCash.Text = strMsg;//显示余额
}