Adding Objects with Display Text to ComboBox and Selecting Them - vb.net

Question

First it is worth it to note that I am very new to Visual Basic. I have created a win forms project in Visual Studio 2012 in the Visual Basic Language.
Given the below code, I want to use a combobox named cmbChoose to select from 4 options. These options will be listed in the combobox as:
"Problem 1"
"Problem 2"
"Problem 3"
"Problem 4"
When a user changes the index of cmbChoose, I would like the class object associated with that index to be set to a parent class object to get polymorphic behavior. A flow of this might be:
User selects "Problem 1".
Parent object problem is set to the class object stored at the index of "Problem 1". This object will be problem1 which is created at the top of the class.
User performs actions, problem1 is the current subclass executing functions
User selects "Problem 3".
Parent object problem is set to the class object stored at the index of "Problem 1". This object will be problem3 which is created at the top of the class.
It seems very simple, and I've read on several posts on stackOverflow to try to get the syntax correct, but I'm doing something wrong. I've made sure the combobox can "Use data bound items", and I've tried to set the DataSource, DisplayMember, and ValueMember in different ways. I've tried to access the object stored at a index in different ways.
I do not want to use conditionals to choose the object, it must be the object at the index chosen.
Here is the code. Assume the Problem classes and subclasses are correctly coded (they are). The functions that will need to be changed/implemented correctly are:
Frm_Base_Load() *or another appropriate function to load the combobox
cmbChoose_SelectedIndexChanged()
Public Class Frm_Base
Private problem As Problem
Private problem1 As Problem1 = New Problem1()
Private problem2 As Problem2 = New Problem2()
Private problem3 As Problem3 = New Problem2()
Private problem4 As Problem4 = New Problem2()
Private Sub btnQuit_Click(sender As Object, e As EventArgs) Handles btnQuit.Click
End
End Sub
Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click
lstTable.Items.Clear()
End Sub
Private Sub btnDoWhile_Click(sender As Object, e As EventArgs) Handles btnDoWhile.Click
problem.DoWhile()
End Sub
Public Sub btnDoUntil_Click(sender As Object, e As EventArgs) Handles btnDoUntil.Click
problem.DoUntil()
End Sub
Public Sub btnForNext_Click(sender As Object, e As EventArgs) Handles btnForNext.Click
problem.Fornext()
End Sub
Private Sub Frm_Base_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'Need to implement
'cmbChoose.DataSource = problem1
'cmbChoose.DisplayMember = "Problem 1"
'cmbChoose.ValueMember = 0
End Sub
Private Sub cmbChoose_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbChoose.SelectedIndexChanged
'Need to change to set parent object 'problem' to sub object at current index
problem = cmbChoose.DataSource
End Sub
End Class

Answer 1

Alright, asuming your Classes are correct this is what you have to do:
In Form_Load:
First create list of Problem
Dim ProbList As New List(Of Problem)
Then add all problems to that List.
ProbList.Add(ProblemX)
Then create a binding source and add the list as datasource
Dim BSProblems As New BindingSource
BSProblems.DataSource = ProbList
Then add the Bindingsource to the combobox.
ComboBox.DataSource = BSProblems
Then add whatever display member you want (I have selected Name, you probably have something different).
ComboBox.DisplayMember = "Name"
Then, in your Problem class you would have to have a property called Name. You create a property like this:
Property Name As String
Notice how it does not say "Public Name..." since that doesn't work (this is a common mistake here).
Finally you have to fetch the Problem base class from SelectedIndexChanged:
problem = CType(ComboBox.SelectedItem, Problem)
Hope this helps you out. Note that the only reason I help you this much is because I had a hard time understanding this myself. Don't expect this kind of help in the future since it does not look like you have tried that many things before posting this question.