c＃界面FPGA实现 - 为什么会发生这种不建？ [英] c# interface implemention - why does this not build?

问题描述

很抱歉，如果这已被问过，但它几乎是不可能的，以谷歌。我认为，一个int数组实现IEnumerable，因此东西应该能够实现IThing。为什么它不？

Sorry if this has been asked before but it's virtually impossible to google. I think that an int array implements IEnumerable and therefore Thing should be able to implement IThing. How come it doesn't?

public interface IThing
{
    IEnumerable<int> Collection { get; }
}

public class Thing : IThing
{
    public int[] Collection { get; set; }
}

注意，

public class Thing : IThing
{
    public int[] Array { get; set; }
    public IEnumerable<int> Collection
    {
         get
         {
              return this.Array;
         }
    }
}

是好的。

推荐答案

该接口的实现必须完全实现的接口。这prevents您返回实现该接口为成员的类型。

The interface implementation must implement the interface exactly. This prevents you from returning a type that implements that interface as the member.

如果你想做到这一点，一个选择是实现该接口的明确的：

If you wish to do this, one option is to implement the interface explicitly:

public interface IThing
{
    IEnumerable<int> Collection { get; }
}

public class Thing : IThing
{
    public int[] Collection { get; set; }
    IEnumerable<int> IThing.Collection { get { return this.Collection; } }
}

这允许你对类使用的具体类型，但接口实现公共API来正确地履行。

This allows your public API for the class to use the concrete type, but the interface implementation to be fulfilled correctly.

例如，与上述情况，你可以这样写：

For example, with the above, you can write:

internal class Test
{
    private static void Main(string[] args)
    {
        IThing thing = new Thing { Collection = new[] { 3, 4, 5 } };

        foreach (var i in thing.Collection)
        {
            Console.WriteLine(i);
        }
        Console.ReadKey();
    }
}

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