Question

MVC 3 VB.NET razor. I have a view that has 4 dropdown boxes in it.. This is for setting up a staff member.. If that staff member is to work certain classes then that class will be set for each day. If he is not then the value needs to stay null. This is a edit view so it may have to be accessed multiple times and still keep the original selectlist values if none changed. The below is what I have right now that is working only on its face. The Old selected value is shown first. However this isnt being returned on the save… The only way that it will save correctly is if I select the value that was set in each box then click save. The next problem is that not all staff members will have classes to work on every one of the 4 days. So how do I set a value to null and keep it that way unless a class Is actually selected..

    Dim _staff As confstaff = db.confstaffs.Single(Function(a) a.id = id)
        ViewBag.role = _staff.Conf_Role.ToString
        ViewBag.confRole = db.conf_roles.ToList
        ViewData("tue_Class") = New SelectList(db.courses.ToList.Where(Function(r) r.course_day = "Tuesday").Select(Function(r) r.course_ref), New With {.value = _staff.tue_class})
        ViewData("wed_Class") = New SelectList(db.courses.ToList.Where(Function(r) r.course_day = "Wednesday").Select(Function(r) r.course_ref), New With {.value = _staff.wed_class})
        ViewData("thur_Class") = New SelectList(db.courses.ToList.Where(Function(r) r.course_day = "Thursday").Select(Function(r) r.course_ref), New With {.value = _staff.thur_class})
        ViewData("fri_Class") = New SelectList(db.courses.ToList.Where(Function(r) r.course_day = "Friday").Select(Function(r) r.course_ref), New With {.value = _staff.fri_class})
        Return View(_staff)

And the view is:

     <label>Tuesday Class</label>
       @Html.DropDownList("tue_class", "Select One")
     <label class="small_spacing">Wednesday Class</label>
        @Html.DropDownList("wed_class", "Select One")
     <label class="small_spacing">Thursday Class</label>
        @Html.DropDownList("thur_class", "Select One")
     <label class="small_spacing">Friday Class</label>
        @Html.DropDownList("fri_class", "Select One")

I already expect someone to point out that I should use a view model instead of viewbag but I dont see how a view model would be practical with there being over 100 different courses but I am open for ideas…

Any Ideas???????

Answer 1

if you look at your page source after the page is loaded you will see your top item set from your viewbag value has no value only text so when it is submitted it thinks you are submitting blank. I ran into this before.

What you need to do is to manually create each of your dropdown lists by iterating through the collection and setting the one that matches your viewbag item to selected, that way you can be sure a selected item has a selected value. I have some Razr code around here somewhere. Will update when I find it.

EDIT

    <select name="Type1" id="Type1">

    <option value=""></option>
     @foreach (var name in ViewBag.BackOfficeTypes)
     {
         if (name == ViewBag.SelectedType1Value)
         {
             <option value="@name" selected="selected">@name</option>
         }
         else
         {
                 <option value="@name">@name</option> 
         }
     }
     </select> 

I have several of these on the same page building from different sets of items. Hope this helps.

EDIT 2

If you want to do it all from codebehind I am not a VB guy but here is a way to do it but you need to change your linq statement to manually create the list items instead of dumping from the toList Method.

var courses = db.getCourses();
   IEnumerable<SelectListItem> selectList = 
    from c in courses
    where c.course_day = "Tuesday"
    select new SelectListItem
    {
        Selected = (c.CourseID == selectedCourseID),
        Text = c.Name,
        Value = c.CourseID.ToString()
    };

If you can translate this into the VB equivalent it might solve your issue instead of building them in the Razor end.