动态 LINQ - 带有 ExpandoObject 的 Groupby 导致错误：没有适用的索引器答案

【问题标题】：Dynamic LINQ - Groupby with ExpandoObject Results in Error: No Applicable Indexer动态 LINQ - 带有 ExpandoObject 的 Groupby 导致错误：没有适用的索引器
【发布时间】：2017-10-05 08:07:45
【问题描述】：

是否可以使用带有 ExpandoObject 的 Dynamic LINQ 执行 GroupBy？

考虑下面的例子；理想情况下，我想要一个 ExpandoObjects 的分组列表。

感谢您的宝贵时间。

var listOfExpandoObjects = new List<ExpandoObject>();
var expandoObject = new ExpandoObject();
((IDictionary<string, object>)expandoObject).Add("DynamicProperty", "RepeatedItem");
((IDictionary<string, object>)expandoObject).Add("OtherProperty", "First");
listOfExpandoObjects.Add(expandoObject);

expandoObject = new ExpandoObject();
((IDictionary<string, object>)expandoObject).Add("DynamicProperty", "RepeatedItem");
((IDictionary<string, object>)expandoObject).Add("OtherProperty", "Second");
listOfExpandoObjects.Add(expandoObject);

var dynamicGroupBy = "new ( it[\"DynamicProperty\"] )";
var groupedItems = listOfExpandoObjects.GroupBy(dynamicGroupBy, "it"); // <------- Error: 'No applicable indexer exists in type 'ExpandoObject''

【问题讨论】：

标签： c# linq dynamic dynamic-linq

【解决方案1】：

我想你想要这样的东西

dynamic expandoObject = new ExpandoObject();
expandoObject.DynamicProperty = " RepeatedItem";
expandoObject.OtherProperty = "First";

dynamic secondExpandoObject = new ExpandoObject();
secondExpandoObject.DynamicProperty = "RepeatedItem";
secondExpandoObject.OtherProperty = "Second";

var listOfExpandoObjects = new List<dynamic> { expandoObject, secondExpandoObject };

var dynamicProperty = "DynamicProperty";

var groupedItems =
    from IDictionary<string, object> expando in listOfExpandoObjects
    group expando by expando[dynamicProperty];

【讨论】：