Remove Listbox item if match not found in VBA - vba

Question

I am writing vba code that will search all listbox items against a entire column in a sheet.
If listbox item not found in Excel sheet column, i want to delete the item from list. I tried few codes, its showing some error as "Could not get list property, Invalid property array index". Below is my code i am using currently.
Private Sub CommandButton1_Click()
Dim itemExistResults As Boolean
Dim myarray()
Dim intItem As Long
myarray = Application.Transpose(Sheet1.Range("a2:a1000"))
For intItem = 0 To ListBox1.ListCount - 1
If IsInArray(ListBox1.List(intItem), myarray) Then
Else
ListBox1.RemoveItem intItem
End If
Next
End Sub
Function IsInArray(stringToBeFound As String, arr As Variant) As Boolean
IsInArray = UBound(Filter(arr, stringToBeFound)) > -1
End Function
Any idea where i am wrong in this code.

Answer 1

You should iterate from the last item of list to the first, because removing items changes their indexation.
Try to change your loop like that:
For intItem = ListBox1.ListCount - 1 To 0 Step -1
If IsInArray(ListBox1.List(intItem), myarray) Then
Else
ListBox1.RemoveItem intItem
End If
Next
I have a tip for you connected with your task, but not exactly with the error described in question.
For this type of task you should use object of Dictionary type instead of iterating through array - it would be much more effective.
I have modified your code to use dictionary. Check it and compare the time each of those solutions need to complete this task - the one with dictionary should be much faster. If you have any questions regarding this code, let me know in comments.
Private Sub CommandButton1_Click()
Dim myArray As Variant
Dim intItem As Long
Dim dict As Object
Dim i As Long
Dim value As Variant
'--- [Loading data into dictionary] ------------------------------------
Set dict = VBA.CreateObject("Scripting.Dictionary")
myArray = Sheet1.Range("A2:A1000")
'Iterate through all the items in array and load them into dictionary.
For i = LBound(myArray) To UBound(myArray)
value = myArray(i, 1)
If Not IsEmpty(value) Then
If Not dict.exists(value) Then
Call dict.Add(value, 0)
End If
End If
Next i
'-----------------------------------------------------------------------
'--- [Comparing ListBox with dictionary] -------------------------------
With ListBox1
For intItem = .ListCount - 1 To 0 Step -1
value = .List(intItem)
If Not dict.exists(value) Then
.RemoveItem intItem
End If
Next
End With
'-----------------------------------------------------------------------
End Sub