select list of related grandchild entities

Question

Trying to get an IEnumerable WorkOrderHeader given the following table structure:

OrderHeader 1:many OrderDetails
OrderDetail 1:1 WorkOrderHeader

Code:

public IEnumerable<WorkOrderHeader> GetInProcessWorkOrdersForOrderBy(OrderHeader orderHeader)
{
    var orderDetails = orderHeader.OrderDetails;
    var workOrders= orderDetails.Select(od => od.WorkOrderHeaders.Where(woh => woh.StatusId < (int)WorkOrderStatus.Complete));
    return workOrders;
}

This is returning a nested IEnumerable<IEnumerable<WorkOrderHeader>> . How do I get just the inner IEnumerable<WorkOrderHeader> ?

Answer 1

我认为您正在寻找SelectMany

var workOrders= orderDetails.SelectMany(od => ...)