List of integer doesn't add a value from database

Question

Dim id As Integer
Dim tempIdList As List(Of Integer)

If dr.Read() Then
      Do
         Dim loc As String
         loc = dr("CurrentLocation").ToString()
         id = dr("ID")
         'tempIdList.Add(dr("ID"))
         'tempIdList.Add(id)
             If loc = comboFrom.Text Then
                  isContinue = True
             End If
      Loop While dr.Read
End If

I have tried those commented code. But I get Object reference not set to an instance of an object.
I tried adding a break point, and it seemed that the list does not get a value, just Nothing whilst id has the value of the ID from the access database.

What is wrong?

possible duplicate of [What is a NullReferenceException and how do I fix it?](http://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-and-how-do-i-fix-it) — sloth, Mar 26 '14 at 10:11

score 2 · Accepted Answer · answered Mar 26 '14 at 10:10

2

tempIdList is probably Nothing. You have to create an instance first with the New keyword:

Dim tempIdList As List(Of Integer) = New List(Of Integer)

answered Mar 26 '14 at 10:10

sloth

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List of integer doesn't add a value from database

1 Answers1