Manipulating ListBoxes as Objects - vba

Question

I am working on a VBA userform that includes ListBoxes.
So far, when I had to manipulate one or more, I always proceeded like this in my subs, with dlg as the dialogbox name, and it did not pose any problem, given that I never wanted to do anything complicated:
Dim List1 As Object
...
List1 = dlg.GetControl("CBXname")
...
List1.addItem("String",index)
...
Now I would like to do the following in this Sub
...
If (List1.Exists(Cell1.String) = False) Then
List1.addItem(Cell1.String,k)
End If
...
List1.Clear
...
But I can do neither since List1 is an Object. However, if I decide to declare List1 as a Listbox instead, I do not know how to get the proper control on the ListBox from the dialogbox (the current getcontrol gives me an error).

Answer 1

One of the issues with your code is that listbox objects do not have an "exists" property. To check if a value already exists in your listbox items, you will need to loop through the items.
dim i as integer
for i = 0 to List1.listcount - 1
if List1.column(0, i) = myvalue then
'myvalue exists in List1, skip
else
List1.additem myvalue
end if
next i
Where myvalue is whatever value you are trying to add to the listbox. But that brings us to the second issue in your code which is where you add "Cell1.String". If you are trying to add a value from a worksheet range you will need to refer to that range's value, as worksheet ranges do not have a "string" property as you use it here. Ie. Cell1 = Range("A1").value
As for getting control of the listbox, you can simply refer to the objects name as an object of the form. For example, dlg.List1, if the object's name is List1.

Answer 2

Here is a general purpose routine you can call for any list box. The calling code assumes a list box called ListBox1, a text box called TextBox1, and a Command Button called CommandButton. When you click on the button, it searches the listbox for the text from textbox1.
Private Function ExistsInListbox(ByRef aListBox As msforms.ListBox, ByVal Item As String) As Boolean
Dim booFound As Boolean
booFound = False
Dim t As Integer
ExistsInListbox = False
For t = 0 To aListBox.ListCount - 1 'correction, aListBox not ListBox1
If Item = aListBox.List(t) Then
'if we find a match, short-circuit the loop
booFound = True
Exit For
End If
Next
ExistsInListbox = booFound
End Function
private sub CommandButton_click()
Dim answer As String
Dim val As Boolean
val = ExistsInListbox(Me.ListBox1, TextBox1.Text)
If val Then
answer = "found"
Else
answer = "Not Found"
End If
MsgBox "found-" & answer
End Sub