c# - 如何实现 GetEnumerator() 和 Dispose()？

Question

我有以下 IAsyncCursor 的包装器类

public sealed class DeferredResultCollection<TResult> : IEnumerable<TResult>, IDisposable
{
    private readonly IAsyncCursor<TResult> _asyncCursor;

    public DeferredResultCollection(IAsyncCursor<TResult> asyncCursor)
    {
        _asyncCursor = asyncCursor;
    }

    public IEnumerator<TResult> GetEnumerator()
    {
        for (; _asyncCursor.MoveNextAsync().Result;)
        {
            foreach (var result in _asyncCursor.Current)
            {
                yield return result;
            }
        }
    }

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

    public void Dispose()
    {
        if (_asyncCursor != null)
        {
            _asyncCursor.Dispose();
        }
    }
}

我是 C# 的新手，我想添加新的构造函数 IList<TResult>并实现新方法 GetEnumerator()和 Dispose()对于 IList<TResult> .这个怎么做？请帮帮我。

Answer 1

所以，如果我理解正确的话，你想从 IAsyncCursor<T> 中提取值或 IList<T> .

这很简单:有两个字段，使用一个不是 null 的字段.

public sealed class DeferredResultCollection<TResult> : IEnumerable<TResult>, IDisposable
{
    private readonly IAsyncCursor<TResult> _asyncCursor;
    private readonly ICollection<TResult> _results;

    public DeferredResultCollection(IAsyncCursor<TResult> asyncCursor)
    {
        if (asyncCursor == null)
            throw new ArgumentNullException(nameof(asyncCursor));

        _asyncCursor = asyncCursor;
    }

    public DeferredResultCollection(ICollection<TResult> results)
    {
        if (results == null)
            throw new ArgumentNullException(nameof(results));

        _results = results;
    }

    public IEnumerator<TResult> GetEnumerator()
    {
        return _results != null
            ? _results.GetEnumerator()
            : GetAsyncCursorEnumerator();
    }

    private IEnumerator<TResult> GetAsyncCursorEnumerator()
    {
        for (; _asyncCursor.MoveNextAsync().Result;)
        {
            foreach (var result in _asyncCursor.Current)
            {
                yield return result;
            }
        }
    }

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

    public void Dispose()
    {
        if (_asyncCursor != null)
        {
            _asyncCursor.Dispose();
        }
    }
}