Question

MVC 3 razor VB.NET project. I have resorted to manual building a list for a drop down box so I can insure certain values are available in the select list and also to control what the first item is in the list. The below is my code snippet for the part that is giving me problems..

      Dim _courses1 As Integer = db.courses.ToList.Where(Function(r) r.course_day = "Tuesday").Count
        Dim _classes1 As List(Of cours) = db.courses.ToList
        Dim classRef1 As List(Of String)
        If Not _selectedClass0 = "--" Then
            classRef1.Add("--")
        Else
            classRef1.Add(_selectedClass0)
        End If
        For i As Integer = 0 To _courses1 - 1
            For Each item In _classes1.Where(Function(f) f.course_day = "Tuesday")
                Dim _item As cours = item
                classRef1.Add(_item.course_ref)
            Next
        Next
        ViewBag.tue1 = classRef1

The _selectedClass0 is just a string that gets set earlier… The error mentioned happens when it gets to the ClassRef1.Add(_selectedClass0) part of the else statement. Which _selectedClass0 string value at the time of error is “–“. I have a feeling it is in how the list is being created but I am not certain… Any ideas???

Answer 1

You’re not initializing classRef1.

 Dim classRef1 As new List(Of String)

Another thing I see is in the first line – I’ve made the changes I see:

Dim _courses1 As Integer = db.courses.Where(Function(r) r.course_day = "Tuesday").Count()

You don’t need ToList at the beginning if all your getting is the count.