LINQ IEnumerable的序列化结果

问题描述

我有一个简单的值类型:

I have a simple value type:

    [Serializable]
    private struct TimerInstance
    {
        public TimerInstance(string str, long nTicks)
        {
            _name = str;
            _ticks = nTicks;
        }

        private readonly string _name;
        private readonly long _ticks;

        public string Name { get { return _name; } }
        public long Ticks { get { return _ticks; } }

        public override string ToString()
        {
            return string.Format("{0,20}: {1,10:N}", Name, Ticks);
        }
    }

您会注意到的

是可序列化的.然后，我列出了这些清单:

which as you'll note is serializable. Then I have a list of these:

static private List<TimerInstance> _Timers = new List<TimerInstance>();

和LINQ方法从列表中消除底部5％和顶部5％的计时器:

and a LINQ method to eliminate the bottom 5% and top 5% of timers from the list:

// Return items that should be persisted.  By convention, we are eliminating the "outlier"
// values which I've defined as the top and bottom 5% of timer values.
private static IEnumerable<TimerInstance> ItemsToPersist()
{
    // Eliminate top and bottom 5% of timers from the enumeration.  Figure out how many items
    // to skip on both ends.
    int iFivePercentOfTimers = _Timers.Count / 20;
    int iNinetyPercentOfTimers = _Timers.Count - iFivePercentOfTimers * 2;

    return (from x in _Timers
            orderby x.Ticks descending
            select x).Skip(iFivePercentOfTimers).Take(iNinetyPercentOfTimers);
}

然后我尝试将该枚举的结果序列化为XML，即仅序列化中间90％的计时器的值，从而消除顶部和底部5％的情况:

I then am trying to Seralize to XML the result of this enumeration, i.e. serialize just the values of the timers in the middle 90%, eliminating the top and bottom 5%:

// Serialize the timer list as XML to a stream - for storing in an Azure Blob
public static void SerializeTimersToStream(Stream s)
{
    BinaryFormatter f = new BinaryFormatter();
    f.Serialize(s, ItemsToPersist());
}

问题是当执行此代码时，我得到了:

The problem is that when this code executes, I get this:

我想我知道这是什么告诉我-枚举数显然已生成的隐式类('System.Linq.Enumerable + d__3a`1 [[TracePerfWorker.TraceTimer + TimerInstance，TracePerfWorker')本身未标记为可序列化的

I think I get what this is telling me - the implicit class that the enumerator has apparently generated ('System.Linq.Enumerable+d__3a`1[[TracePerfWorker.TraceTimer+TimerInstance, TracePerfWorker') is not itself marked as serializable.

但是，这似乎是一种非常普遍的情况，在这种情况下，我正在使用可序列化的值类型(TimerInstance)，并且仅在这些值的列表上构建LINQ查询，即枚举器仅返回TimerInstance值-然后我如何说服枚举器返回的仅仅是TimerInstance值的列表，这些列表是可序列化的?

But this seems like a really common situation, where I'm taking a serializable value type(TimerInstance), and just building a LINQ query over a list of these values, i.e. the enumerator is just returning TimerInstance values - how do I then convince it that what the enumerator is returning is just a list of TimerInstance values, which are serializable?

推荐答案

在调用序列化之前如何使用ToList获取项目列表?您的方法将需要更改为返回List<TimerInstance>而不是IEnumerable<TimerInstance>

How about using ToList to get a list of items before you call serialize?Your method will need to be changed to return a List<TimerInstance> instead of IEnumerable<TimerInstance>

http://msdn.microsoft.com/en-us/library/bb342261.aspx

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