如何正确模拟 HttpSessionStateBase 中的 KeysCollection？

Question

我在此处的示例中设置了这个模拟会话对象：How to MOQ an Indexed property

/// <summary>
/// HTTP session mockup.
/// </summary>
internal sealed class HttpSessionMock : HttpSessionStateBase
{
    private readonly Dictionary<string, object> objects = new Dictionary<string, object>();

    public override object this[string name]
    {
        get { return (objects.ContainsKey(name)) ? objects[name] : null; }
        set { objects[name] = value; }
    }
}

一些产生错误的示例代码...

var mockSession = new HttpSessionMock();
var keys = mockSession.Keys;

错误：方法或操作未实现。

我需要实现 Keys 属性，但无法创建 KeysCollection 对象。

最好的方法是什么？

编辑：[解决方案]

我最终根据给出的答案更改了 HttpSessionMock。这就是我最终的结果。 （我还添加了对 System.Linq 的引用）。

internal sealed class HttpSessionMock : HttpSessionStateBase
{
    private readonly NameValueCollection objects = new NameValueCollection();

    public override object this[string name]
    {
        get { return (objects.AllKeys.Contains(name)) ? objects[name] : null; }
        set { objects[name] = (string)value; }
    }

    public override NameObjectCollectionBase.KeysCollection Keys
    {
        get { return objects.Keys; }
    }
}

注意：这个模拟会话将只存储字符串，而不是对象。

Answer 1

我发现原始方法和公认解决方案的组合允许存储对象和实现 keys 属性：

public class HttpSessionMock : HttpSessionStateBase
{
    private readonly NameValueCollection keyCollection = new NameValueCollection();
    private readonly Dictionary<string, object> objects = new Dictionary<string, object>();

    public override object this[string name]
    {
        get
        {
            object result = null;

            if (objects.ContainsKey(name))
            {
                result = objects[name];
            }

            return result;

        }
        set
        {
            objects[name] = value;
            keyCollection[name] = null;
        }
    }

    public override NameObjectCollectionBase.KeysCollection Keys
    {
        get { return keyCollection.Keys; }
    }
}

Answer 2

一种方式：

internal sealed class HttpSessionMock : HttpSessionStateBase
{
    public override NameObjectCollectionBase.KeysCollection Keys
    {
        get { return _collection.Keys; }
    }

    private readonly NameValueCollection _collection = new NameValueCollection();
}

Answer 3

更新： 供您参考，下面是 .NET 框架中 KeysCollection 的源代码：

public class KeysCollection : ICollection, IEnumerable
{
    // Fields
    private NameObjectCollectionBase _coll;

    // Methods
    internal KeysCollection(NameObjectCollectionBase coll)
    {
        this._coll = coll;
    }

    public virtual string Get(int index)
    {
        return this._coll.BaseGetKey(index);
    }

    public IEnumerator GetEnumerator()
    {
        return new NameObjectCollectionBase.NameObjectKeysEnumerator(this._coll);
    }

    void ICollection.CopyTo(Array array, int index)
    {
        if (array == null)
        {
            throw new ArgumentNullException("array");
        }
        if (array.Rank != 1)
        {
            throw new ArgumentException(SR.GetString("Arg_MultiRank"));
        }
        if (index < 0)
        {
            throw new ArgumentOutOfRangeException("index", SR.GetString("IndexOutOfRange", new object[] { index.ToString(CultureInfo.CurrentCulture) }));
        }
        if ((array.Length - index) < this._coll.Count)
        {
            throw new ArgumentException(SR.GetString("Arg_InsufficientSpace"));
        }
        IEnumerator enumerator = this.GetEnumerator();
        while (enumerator.MoveNext())
        {
            array.SetValue(enumerator.Current, index++);
        }
    }

    // Properties
    public int Count
    {
        get
        {
            return this._coll.Count;
        }
    }

    public string this[int index]
    {
        get
        {
            return this.Get(index);
        }
    }

    bool ICollection.IsSynchronized
    {
        get
        {
            return false;
        }
    }

    object ICollection.SyncRoot
    {
        get
        {
            return ((ICollection) this._coll).SyncRoot;
        }
    }
}