Get a value by index from combobox class - vb.net

Question

i'm approaching to vbnet from vb6 and i'm triyng to get value from combobox using a class which contains the values i stored in.
here is the class
Private m_ItemText As String
Private m_ItemIndex As Int32
Public Sub New(ByVal strItemText As String, ByVal intItemIndex As Int32)
m_ItemText = strItemText
m_ItemIndex = intItemIndex
End Sub
Public ReadOnly Property ItemIndex() As Int32
Get
Return m_ItemIndex
End Get
End Property
Public ReadOnly Property ItemText() As String
Get
Return m_ItemText
End Get
End Property
I use this method charge the combobox
ComboBox2.Items.Add(New clsComboBoxItem("sometext", 1))
ComboBox2.Items.Add(New clsComboBoxItem("sometext 2", 2))
ComboBox2.Items.Add(New clsComboBoxItem("sometext", 3))
and this on combobox.selectedindexchanged
If ComboBox2.SelectedItem.GetType.ToString = itmCombo.GetType.ToString Then
itmCombo = CType(ComboBox2.SelectedItem, clsComboBoxItem)
MessageBox.Show("Item Text=" & itmCombo.ItemText & " and ItemIndex=" & CStr(itmCombo.ItemIndex))
End If
Can anyone tell help me to understand how get an element by his index stored in the class? Eg writing '2' into a text box, the combo box sould be show "sometext2".
Suppose i want to expand the class adding some values, like m_ItemText2,m_ItemText3 etc, i would learn a method to get all of theese values.
I hope I was clear
Thanks in advance

Answer 1

If you have a DataSource set to a DataTable for your ComboBox, just set the DisplayMember and ValueMember. My test ComboBox is set to DropDownList.
Private Sub FillComboBox()
Dim dt As New DataTable
Using con As New SqlConnection(ConStr),
cmd As New SqlCommand("Select FlavorID,FlavorName From Flavors", con)
con.Open()
Using reader = cmd.ExecuteReader
dt.Load(reader)
End Using
End Using
ComboBox1.DisplayMember = "FlavorName"
ComboBox1.ValueMember = "FlavorID"
ComboBox1.DataSource = dt
End Sub
To display the the values
To display the Text cast to DataRowView (that is the object that is in the Item), provide the field you want and call ToString.
Private Sub ComboBox1_SelectionChangeCommitted(sender As Object, e As EventArgs) Handles ComboBox1.SelectionChangeCommitted
MessageBox.Show(ComboBox1.SelectedValue.ToString)
MessageBox.Show(DirectCast(ComboBox1.SelectedItem, DataRowView)("FlavorName").ToString)
End Sub
If you are adding items one by one, you can still set the DisplayMember and ValueMember.
'https://stackoverflow.com/questions/38206678/set-displaymember-and-valuemember-on-combobox-without-datasource
Private Sub SomeFormsLoadEvent()
ComboBox1.Items.Add(New KeyValuePair(Of String, Integer)("Ultra-fast", 600))
ComboBox1.Items.Add(New KeyValuePair(Of String, Integer)("Fast", 300))
ComboBox1.Items.Add(New KeyValuePair(Of String, Integer)("Medium", 150))
ComboBox1.Items.Add(New KeyValuePair(Of String, Integer)("Slow", 75))
ComboBox1.DisplayMember = "Key"
ComboBox1.ValueMember = "Value"
ComboBox1.DataSource = ComboBox1.Items
End Sub
I found it a bit more complicated to display the text. I had to cast the item to its underlying type (KeyValuePair) then ask for the Key value.
Private Sub ComboBox1_SelectionChangeCommitted(sender As Object, e As EventArgs) Handles ComboBox1.SelectionChangeCommitted
MessageBox.Show(ComboBox1.SelectedValue.ToString)
MessageBox.Show(DirectCast(ComboBox1.SelectedItem, KeyValuePair(Of String, Integer)).Key)
End Sub

Answer 2

As I understand it you want to store values in a class and display and access them through the combobox. How about this approach:
The class for the values:
Public Class clsValues
Private lstItemTexts As New List(Of String)
Public ReadOnly Property AllValues As List(Of String)
Get
Return lstItemTexts
End Get
End Property
'To initialize class with empty list, items can be added with AddItems
Public Sub New()
End Sub
'To initialize class with items, items can still be added with AddItems
Public Sub New(lstItemTexts As List(Of String))
Me.lstItemTexts = lstItemTexts
End Sub
Public Sub AddItem(item As String)
Me.lstItemTexts.Add(item)
End Sub
Public Function GetItemByIndex(index As Integer) As String
Return lstItemTexts(index)
End Function
Public Function GetIndexByItem(item As String) As Integer
Return lstItemTexts.IndexOf(item)
End Function
End Class
You can declare it and fill values like this:
Private Values As New clsValues()
Values.AddItem("Some Text 1")
Values.AddItem("Some Text 2")
or
Private Values As New clsValues(New List(Of String)({"Some Text 1", "Some Text 2"}))
to get a value from combobox
Private Sub ComboBox2_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox2.SelectedIndexChanged
MessageBox.Show(Values.GetItemByIndex(ComboBox2.SelectedIndex))
End Sub

Answer 3

What #Mary stated is true the ComboBox has values that are useful SEE CODE BELOW
Change gvTxType to be a TextBox to see results when you click on the tvTxType
Private Sub cbTxType_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cbTxType.SelectedIndexChanged
If cbTxType.SelectedIndex > -1 Then
'Dim sindex As Integer
'sindex = cbTxType.SelectedIndex
'Dim sitem As String
sitem = CType(cbTxType.SelectedItem, String)
'MsgBox("You Selected " & sitem)
'Index is ZERO based
gvTxType = sitem
End If
End Sub