如何配置Unity为IEnumerable注入数组 [英] How to configure Unity to inject an array for IEnumerable

问题描述

我有一个带有 IEnumerable 构造函数参数的类，我想用Unity解析它并注入一个对象数组。这些简单的类说明了问题。

I have a class which takes an IEnumerable constructor parameter which I want to resolve with Unity and inject an array of objects. These simple classes illustrate the problem.

public interface IThing
{
    int Value { get; }
}

public class SimpleThing : IThing
{
    public SimpleThing()
    {
        this.Value = 1;
    }

    public int Value { get; private set; }
}

public class CompositeThing : IThing
{
    public CompositeThing(IEnumerable<IThing> otherThings)
    {
        this.Value = otherThings.Count();
    }

    public int Value { get; private set; }
}

说我想注入四个 SimpleThing 转到 CompositeThing 。我已经尝试了以下Unity配置的几种变体。

Say I want to inject four SimpleThing in to CompositeThing. I've tried several variations on the following Unity configuration.

<alias alias="IThing" type="TestConsoleApplication.IThing, TestConsoleApplication" />
<alias alias="SimpleThing" type="TestConsoleApplication.SimpleThing, TestConsoleApplication" />
<alias alias="CompositeThing" type="TestConsoleApplication.CompositeThing, TestConsoleApplication" />

<container>

  <register type="IThing" mapTo="SimpleThing" name="SimpleThing" />
  <register type="IThing" mapTo="CompositeThing" name="CompositeThing">
    <constructor>
      <param name="otherThings">
        <array>
          <dependency type="SimpleThing"/>
          <dependency type="SimpleThing"/>
          <dependency type="SimpleThing"/>
          <dependency type="SimpleThing"/>
        </array>
      </param>
    </constructor>
  </register>

</container>

但是我收到错误消息配置已设置为注入数组，但类型IEnumerable`1不是数组类型。如果我将构造函数参数更改为 IThing [] 可行，但我不想这样做。我需要对Unity配置进行什么操作才能使其正常工作？

However I get the error message The configuration is set to inject an array, but the type IEnumerable`1 is not an array type. If I change the constructor parameter to be IThing[] it works, but I don't want to do that. What do I need to do to my Unity configuration to get this to work?

推荐答案

这是我找到的一种解决方案，但是有点n您需要一个包装器类来帮助Unity识别数组是 IEnumerable 。

Here's one solution that I've found, but it's a bit naff. You need a wrapper class to help Unity recognise that an array is IEnumerable.

public class ArrayWrapper<T> : IEnumerable<T>
{
    public ArrayWrapper(T[] things)
    {
        this.things = things;
    }

    private IEnumerable<T> things;

    IEnumerator<T> IEnumerable<T>.GetEnumerator()
    {
        return this.things.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return this.things.GetEnumerator();
    }
}

然后您可以配置Unity注入其中之一，使用Ethan的 EnumberableThing 想法。

You can then configure Unity to inject one of these, using Ethan's EnumberableThing idea.

<alias alias="IThing" type="TestConsoleApplication.IThing, TestConsoleApplication" />
<alias alias="SimpleThing" type="TestConsoleApplication.SimpleThing, TestConsoleApplication" />
<alias alias="CompositeThing" type="TestConsoleApplication.CompositeThing, TestConsoleApplication" />
<alias alias="EnumerableThing" type="System.Collections.Generic.IEnumerable`1[[TestConsoleApplication.IThing, TestConsoleApplication]], mscorlib"/>
<alias alias="ThingArrayWrapper" type="TestConsoleApplication.ArrayWrapper`1[[TestConsoleApplication.IThing, TestConsoleApplication]], TestConsoleApplication"/>

<container>
  <register type="EnumerableThing" mapTo="ThingArrayWrapper">
    <constructor>
      <param name="things">
        <array>
          <dependency type="SimpleThing"/>
          <dependency type="SimpleThing"/>
          <dependency type="SimpleThing"/>
          <dependency type="SimpleThing"/>
        </array>
      </param>
    </constructor>
  </register>

  <register type="IThing" mapTo="SimpleThing" name="SimpleThing" />

  <register type="IThing" mapTo="CompositeThing" name="CompositeThing">
    <constructor>
      <param name="otherThings" dependencyType="EnumerableThing" />
    </constructor>
  </register>
</container>

就像我说的那样，当您想要另一个包含三，五，六种东西的 CompositeThing 时，有点麻烦和尴尬。

Like I say though, a bit naff and awkward when you want another CompositeThing with three, five, six things etc.

当然，Unity应该是能够识别一个数组是 IEnumberable 并注入它的？

Surely Unity should be able to recognise that an array is IEnumberable and inject it?

这篇关于如何配置Unity为IEnumerable注入数组的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！