Question

我试图通过以下代码对列表进行分组

var b = groupBy(value[index],(ABC item) => item.id);
dropDownMenuItem = buildDropDownMenuItems(b.values);

b现在为Map<String, List<ABC>>

在buildDropDownMenuItems中，我想通过List<ABC>

List<DropdownMenuItem<ABC>> buildDropDownMenuItems(List<ABC> asset) {
  ......
  }

错误

不能将参数类型“ Iterable>”分配给参数类型“列表”。

Answer 1

在searchParams.UseLast = Convert.ToBoolean(base.Arguments["UseLast"]); searchParams.LastEditedFrom= Convert.ToDateTime(base.Arguments["LastEditedFrom"]); searchParams.LastEditedTo = Convert.ToDateTime(base.Arguments["LastEditedTo"]); searchParams.Reviewed = Convert.ToBoolean(base.Arguments["Reviewed"]); searchParams.Approved = Convert.ToBoolean(base.Arguments["Approved"]); searchParams.Include = Convert.ToBoolean(base.Arguments["Include"]); searchParams.IsVisibleToUser = Convert.ToBoolean(base.Arguments["IsVisibleToUser"]); searchParams.IsEntry = Convert.ToBoolean(base.Arguments["IsEntry"]); searchParams.UserId = Convert.ToInt32(base.Arguments["UserId"]); IEnumerable Categories = base.Arguments["Categories"] as IEnumerable; IEnumerable Departments = base.Arguments["Departments"] as IEnumerable; String mQuery = "How to construct it ....!!!" // Need help in this var query = queryParser.Parse(mQuery); indexSearcher.Search(query, collector);上尝试expand功能

values

但是很明显，它在var b = groupBy(value[index],(ABC item) => item.id); dropDownMenuItem = buildDropDownMenuItems(b.values.expand((item) => item).toList());函数之前为您提供了相同的未分组列表。可能您想将其用作group by

b["your key"]

无法将参数类型“ Iterable>”分配给参数类型“ List”

1 个答案: