Question

我正在尝试使用工厂模式制作自定义对象。理想情况下，我希望有一些可以继承的基础对象，但specifc对象可以像基础对象一样工作，并且只能执行它可以执行的特定任务。我似乎无法通过新创建的对象访问基础对象的数据。我看了一些教程，并拼凑了我认为应该起作用但碰壁的东西。

现在，我正在通过实例化一家工厂来这样做，以便以后进行测试时更容易。我试图通过不使其抽象化来直接访问FilterPanel，但是我不确定这是一种好的编码实践。

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该成员。

//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();
}

使用初始化工厂和继承创建自定义对象

1 个答案: