从C＃泛型对象获取属性 [英] Get Property from a generic Object in C#

问题描述

看看这段代码，请：

public void BindElements<T>(IEnumerable<T> dataObjects)
{
    Paragraph para = new Paragraph();

    foreach (T item in dataObjects)
    {
        InlineUIContainer uiContainer =
            this.CreateElementContainer(item.FirstName ????? )              
        para.Inlines.Add(uiContainer);
    }                         

    FlowDocument flowDoc = new FlowDocument(para);
    this.Document = flowDoc;
}

当在Visual Studio写item.XXX我应该得到的属性从我entitiy像.FirstName或.LastName。我不知道羯羊数据对象是一个IEnumerable或IOrder等...它必须是通用的吧！

When in write in Visual Studio "item.XXX" I should get the properties from my entitiy like .FirstName or .LastName. I do not know wether dataObjects is an IEnumerable or IOrder etc... it must be generic!

我怎样才能得到真正的性质形成项目？只有反思？

推荐答案

的俄德是正确，它似乎并没有（对他或我）作出任何有意义的尝试，使这个方法通用的。您正在尝试泛化其功能实际上是专门针对几类的方法。

Oded is right, it doesn't seem (to him or me) to make any sense to try and make this method generic. You are trying to genericize a method whose functionality is actually specific to a few types.

现在，这么说，看来的散的的功能是独立的，你要访问这个属性。那么，为什么不把它拆分成两部分：即可以泛型化，而哪些不能：

Now, that said, it seems the bulk of the function is independent of this property you want to access. So why not split it into two parts: that which can be genericized, and that which can't:

事情是这样的：

void BindElements<T, TProperty>(IEnumerable<T> dataObjects,
                                Func<T, TProperty> selector)
{
    Paragraph para = new Paragraph();

    foreach (T item in dataObjects)
    {
       // Notice: by delegating the only type-specific aspect of this method
       // (the property) to (fittingly enough) a delegate, we are able to 
       // package MOST of the code in a reusable form.
       var property = selector(item);

       InlineUIContainer uiContainer = this.CreateElementContainer(property)
       para.Inlines.Add(uiContainer);
    }

    FlowDocument flowDoc = new FlowDocument(para);
    this.Document = flowDoc;
}

那么你的重载处理特定类型，例如， IPerson ，可重用的代码（我怀疑可能是你是什么毕竟沿代码重用）：

Then your overloads dealing with specific types, e.g., IPerson, can reuse this code (which I suspect may be what you were after all along—code reuse):

public void BindPeople(IEnumerable<IPerson> people)
{
    BindElements(people, p => p.FirstName);
}

...然后 IOrder ：

public void BindOrders(IEnumerable<IOrder> orders)
{
    BindElements(orders, o => p.OrderNumber);
}

...等。

...and so on.

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