Question

我正在使用字典包装器类，我想使用键值对迭代它，如下所示

private void LoadVariables(LogDictionary dic)
{
    foreach (var entry in dic)
    {
        _context.Variables[entry.Key] = entry.Value;
    }

}

但抛出了NotImplementedException，因为我没有实现GetEnumerator()方法。

这是我的包装类：

public class LogDictionary: IDictionary<String, object>
{
    DynamicTableEntity _dte;
    public LogDictionary(DynamicTableEntity dte)
    {
        _dte = dte;
    }
        bool ICollection<KeyValuePair<string, object>>.Remove(KeyValuePair<string, object> item)
    {
        throw new NotImplementedException();
    }

    IEnumerator<KeyValuePair<string, object>> IEnumerable<KeyValuePair<string, object>>.GetEnumerator()
    {
        throw new NotImplementedException();
    }

    System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
    {
        throw new NotImplementedException();
    }
}

Answer 1

假设您在枚举期间没有包装器需要的特殊逻辑，您只需将调用转发到包含的实例：

public class LogDictionary: IDictionary<String, object>
{
    DynamicTableEntity _dte;
    public LogDictionary(DynamicTableEntity dte)
    {
        _dte = dte;
    }
        bool ICollection<KeyValuePair<string, object>>.Remove(KeyValuePair<string, object> item)
    {
        throw new NotImplementedException();
    }

    IEnumerator<KeyValuePair<string, object>> IEnumerable<KeyValuePair<string, object>>.GetEnumerator()
    {
        return _dte.GetEnumerator();
    }

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

Answer 2

您需要在内部实施一个列表或词典来保存LogDictionary的值。

我不知道DynamicTableEntity是什么，我会假设它实现了IDictionary<string,object>。

public class LogDictionary: IDictionary<String, object>
{
    private IDictionary<String, object> _dte;

    public LogDictionary(DynamicTableEntity dte)
    {
        _dte = (IDictionary<String, object>)dte;
    }

    bool ICollection<KeyValuePair<string, object>>.Remove(KeyValuePair<string, object> item)
    {
        return _dte.Remove(item.Key);
    }

    IEnumerator<KeyValuePair<string, object>> IEnumerable<KeyValuePair<string, object>>.GetEnumerator()
    {
        return _dte.GetEnumerator();
    }

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

Answer 3

也许你应该从Dictionary（而不是IDictionary）派生并调用base，而不是在方法中抛出异常。

在包装器字典类中实现IEnumerable.GetEnumerator（）

3 个答案: