在asp.net mvc中使用selectlist的dropdownbox的选定值

Question

我有下面的aspnet mvc中的dropdownbox选择列表。因为“SelectList”需要3个参数一个用于值，一个用于文本，另一个用于选定的值，这里我是一个EditEmployee Action控制器，所以当显示编辑页面时，我想在下拉框中显示一个selectvalue，米没有得到什么，我应该通过第三个参数，因为它要求一个对象的选定值。

 

ViewData["DepartmentList"] = new SelectList(DepartmentRepository.GetDepartmentsBySchoolIdInList(ViewData["schoolId"].ToString()),"DepartmentId","DepartmentTitle"); 
 

这里是

 

=Html.DropDownList("DepartmentList") 
 

Answer 1

var deptList = DepartmentRepository.GetDepartmentsBySchoolIdInList(ViewData["schoolId"].ToString()); 

ViewData["DepartmentList"] = new SelectList(DepartmentRepository.GetDepartmentsBySchoolIdInList(deptList,"DepartmentId",deptList.First());