LINQ的问题查询数据

Question

这里的两个集合是我一起工作的代码：

 Collection<WorkOrderLabor> workOrder = new Collection<WorkOrderLabor>(); 
     Collection<ServiceItem> serviceItems = new Collection<ServiceItem>(); 

     serviceItems = from si in serviceItems 
         join cw in workOrder on si.ServiceKey equals cw.Key 
         select new { si }; 

     foreach (ServiceItem item in serviceItems) 
      ctrl.Items.Add(...); 

我收到此错误：

Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<AnonymousType#1>' to 'System.Collections.ObjectModel.Collection<ServiceItem>' 

我相信这是希望一个简单的办法，但我无法弄清楚。这背后的逻辑是我需要根据传递给此方法的键来查找工作订单，然后获取工单所有的服务项目并遍历它们以将它们放入组合框中。

Answer 1

应该只是

Collection<WorkOrderLabor> workOrder = new Collection<WorkOrderLabor>(); 
Collection<ServiceItem> serviceItems = new Collection<ServiceItem>(); 

var filteredItems = from si in serviceItems 
        join cw in workOrder on si.ServiceKey equals cw.Key 
        select si; 

foreach (ServiceItem item in filteredItems) 
    ctrl.Items.Add(...); 

你不想返回匿名类型从LINQ表达的IEnumerable<>而是一个IEnumerable<ServiceItem>