Loop Combobox and variable inside - vb.net

Question

I have this code:
Dim val1,val2,val3,val4,val5, ... ,val20 As String
If Combobox1.SelectedIndex = 0 Then
val1=">"
else
val1="<"
end if
If Combobox2.SelectedIndex = 0 Then
val2=">"
else
val2="<"
end if
How can I loop this? There are 20 Combo boxes. Please help! Thanks

Answer 1

To loop through the controls on the form, use Me.Controls. And to check the type of the control, use Control.GetType.Name.
The problem is that separate variables like val1,val2,val3...etc cannot be easily used in a loop, so I recommend changing them to a list.
Dim val As New List(Of String)
For Each MyControl In Me.Controls
If MyControl.GetType.Name = "ComboBox" Then
Dim MyComboBox As ComboBox = CType(MyControl, ComboBox)
If MyComboBox.SelectedIndex = 0 Then
val.Add(">")
Else
val.Add("<")
end if
End If
Next

Answer 2

So, here are some looping sequences for you. disclaimer - code is not tested, could be bugs but logical layout should be correct
Private _numOfControls As Integer = 20
Private _variables As New Dictionary(Of String, String)(_numOfControls)
Private Sub Setup()
For i as integer = 1 To _numOfControls
Dim cboName As String = "cbo" & i
Dim cbo As New ComboBox()
cbo.Name = cboName
cbo.SelectedIndex = 0
' Add cbo location according to your logic here
container.Controls.Add(cbo) ' container - any control or form that hosts cbo
_variables.Add(cboName, ">")
AddHandler cbo.SelectedIndexChanged, AddressOf OnCboSelectedIndexChanged
Next
End Sub
' If you do this way, your control-related variable will have appropriate equality sign without need for iteration
Private Sub OnCboSelectedIndexChanged (sender As Object, e As EventArgs)
Dim cbo As ComboBox = CType(sender, ComboBox)
myDict(cbo.Name) = If(cbo.SelectedIndex = 0, ">", "<")
End Sub
' But if you do not want to do in the above^^ way, you can iterate dictionary
Private Sub FromDictionaryToCbo()
' Here you can't use for-loop on dictionary because your dictionary will be mutating. So lets iterate keys
For Each k As String In _variables.Keys.ToArray())
_variables(k) = If(CType(container.Find(k, True), ComboBox).SelectedIndex = 0, ">", "<")
Next
End Sub
' And iterating combo boxes would be something similar as another answer here
' But we use our naming convention to bypass other controls
Private Sub FromCboToDictionary()
Dim c As Control
For i As Integer = 1 To < _numOfControls
Dim key As String = "cbo" & i.ToString()
'We don't know, may be there some other combo boxes are there, so we use our naming convention instead of control type
c = container.Find(key, True)
If c IsNot Nothing Then
_variables(key) = If(CType(c, ComboBox).SelectedIndex = 0, ">", "<")
end If
Next
End Sub