2列表，使用下拉菜單選擇1個列表中的剩餘值

Question

因此，在此頁面中，它將顯示當前subcontractors在這個特定BOQ上工作的列表。這存儲在'allSubContractors'

這顯示爲屏幕上的列表。然後，我想添加一個下拉框，允許用戶選擇任何剩餘的分包商並將其添加到列表中。

到目前爲止，第一部分工作，在BOQ顯示屏上工作的當前子附件工作列表，但對於下拉，我已經完全與我想要的相反。 拖放顯示當前分包商的相同列表，我想要剩下的列表中。

我使用：

`List<string> allSubContractors = new List<string>(); 
     ClarkeDBDataContext db = new ClarkeDBDataContext(); 
     allSubContractors = (from BoqSUBContractors in db.BOQ_SubContractors 
          where BoqSUBContractors.Bill_Of_Quantity_id == this.boqId 
          select BoqSUBContractors.Sub_Contractor.Company_Name).ToList(); 

     repeaterShowSubContractorName.DataSource = allSubContractors; 
     repeaterShowSubContractorName.DataBind(); 


    List<Sub_Contractor> availableSubContractors = new List<Sub_Contractor>(); 
    ClarkeDBDataContext db1 = new ClarkeDBDataContext(); 
    availableSubContractors = (from sc in db1.Sub_Contractors 
           from bsc in db1.BOQ_SubContractors 
           where sc.id == bsc.Sub_Contractor_id 
           && bsc.Bill_Of_Quantity_id == this.boqId 
           select sc).ToList(); 

    DropDownListSubContractors.DataSource = availableSubContractors; 
    DropDownListSubContractors.DataBind(); 

我嘗試類似：

List<Sub_Contractor> availableSubContractors = new List<Sub_Contractor>(); 
    availableSubContractors = (from sc in db.Sub_Contractors 
           select sc.id).ToList() 
           .Except(allSubContractors); 

但諾伊喜悅，有什麼建議？ Thaks

Answer 1

如果你嘗試

List<Sub_Contractor> availableSubContractors = 
(
    from sc in db1.Sub_Contractors 
    join bsc in db1.BOQ_SubContractors 
    on sc.id equals bsc.Sub_Contractor_id 
    where bsc.Bill_Of_Quantity_id equals this.boqId 
    select sc 
).ToList(); 

？