关于c＃：Dynamic + linq编译错误

Dynamic + linq compilation error

我会在前面说，我正在用动态数据上的LINQ做一些非常可怕的事情。但我不明白为什么这个查询不能编译：

错误1属性"<>h_u transparentIdentifier0"不能与类型参数一起使用

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public class Program
{
public static void Main(string[] args)
{
var docs = new dynamic[0];
var q = from doc in docs
where doc["@metadata"]["Raven-Entity-Name"] =="Cases"
where doc.AssociatedEntities != null
from entity in doc.AssociatedEntities
where entity.Tags != null // COMPILER ERROR HERE
from tag in entity.Tags
where tag.ReferencedAggregate != null
select new {tag.ReferencedAggregate.Id, doc.__document_id};
}
}

public static class LinqOnDynamic
{
private static IEnumerable<dynamic> Select(this object self)
{
if (self == null)
yield break;
if (self is IEnumerable == false || self is string)
throw new InvalidOperationException("Attempted to enumerate over" + self.GetType().Name);

foreach (var item in ((IEnumerable) self))
{
yield return item;
}
}

public static IEnumerable<dynamic> SelectMany(this object source,
Func<dynamic, int, IEnumerable<dynamic>> collectionSelector,
Func<dynamic, dynamic, dynamic> resultSelector)
{
return Enumerable.SelectMany(Select(source), collectionSelector, resultSelector);
}

public static IEnumerable<dynamic> SelectMany(this object source,
Func<dynamic, IEnumerable<dynamic>> collectionSelector,
Func<dynamic, dynamic, dynamic> resultSelector)
{
return Enumerable.SelectMany(Select(source), collectionSelector, resultSelector);
}

public static IEnumerable<dynamic> SelectMany(this object source,
Func<object, IEnumerable<dynamic>> selector)
{
return Select(source).SelectMany<object, object>(selector);
}

public static IEnumerable<dynamic> SelectMany(this object source,
Func<object, int, IEnumerable<dynamic>> selector)
{
return Select(source).SelectMany<object, object>(selector);

}
}

为了增加对伤害的侮辱，以下工作：

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var docs = new dynamic[0];
var q = from doc in docs
where doc["@metadata"]["Raven-Entity-Name"] =="Cases"
where doc.AssociatedEntities != null
from entity in doc.AssociatedEntities
where entity.Tags != null
from tag in entity.Tags
select new { tag.ReferencedAggregate.Id, doc.__document_id };

只有当我加上：

其中tag.referencedAggregate！=空

我之前有两行出错：

哪里实体。标签！=空//此处出现编译器错误

不知道发生了什么事

如果我尝试将您的呼叫转换为：

1 2	var q = from doc in docs.Where(doc => doc["@metadata"]["Raven-Entity-Name"] =="Cases" \|\| doc.AssociatedEntities != null) from entity in doc.AssociatedEntities.Where(entity => entity.Tags != null)

我得到了一个不同的编译器错误，它可能揭示了正在发生的事情：

'如果不首先将lambda表达式强制转换为委托或表达式树类型，则不能将其用作动态调度操作的参数'

所以我想你必须让where操作符过载。