使用初始化工厂和继承创建自定义对象

Question

我试图使用工厂模式来定制一个对象。理想情况下，我希望有一些可以继承的基本对象，但是指定的对象可以像基本对象那样工作，也可以只执行特定的任务。我似乎无法通过新创建的对象访问基本对象的数据。我已经看了一些教程，拼凑出我认为应该有效的东西，但却碰壁了。

现在，我正在通过实例化一个工厂来实现这一点，以便以后更容易进行测试。我试图直接访问FilterPanel，方法是不使其抽象，但我不确定这是一个好的编码实践。

为什么我无法访问FilterPanel函数？

FilterPanel

public abstract class FilterPanel {

    //Do generic stuff that all filters can do.
    public void ClickFilterButtons(){...}
}

FilterFactory

    public class FilterFactory {

    public FilterPanel CreateFilterPanel(string filterType) {

        FilterPanel filterPanel;
        switch (filterType) {

            case "invoice":
                filterPanel = new InvoiceFilter();
                break;

            case "payment":
                filterPanel = new PaymentFilter();
                break;

            default:
                throw new Exception("wrong filter!");
                break;
        }
        return filterPanel;
    }
}

public class InvoiceFilter : FilterPanel {

    //Do specific stuff only Invoice filter can do.
    public void InvoiceStuff(){...}
}

public class PaymentFilter : FilterPanel {

    //Do specific stuff only payment filter can do.
    public void PaymentStuff(){...}
}

TestFile

        [Test]
        FilterFactory filter = new FilterFactory();
        filter.CreateFilterPanel("invoice");

        //Cannot access this function in the base filter class functions.
        filter.ClickFilterButtons();

Answer 1

您似乎试图在错误的对象上调用成员。

//Create the factory
FilterFactory factory = new FilterFactory();
//Create the filter using the factory
FilterPanel filter = factory.CreateFilterPanel("invoice");
//Call the public member on the returned filter
filter.ClickFilterButtons();
//To access InvoiceFilter specific stuff you need to cast
if(filter is InvoiceFilter) {
    (filter as InvoiceFilter).InvoiceStuff();
}