access vba: go to next iteration on error - vba

Question

Listbox2 is populated from items in a table, which itself is populated from listbox1. An error will be thrown if an attempted addition to the table contains duplicate keys. I want my code to handle the error by skipping the problem iteration in question, instead of stopping halfway through the loop.
My code looks something like this:
Public Sub CopySelected(ByRef frm As Form)
Dim ctlSource As Control
Dim intCurrentRow As Integer
Set ctlSource = Me!listbox1
On Error GoTo nonrelation
Dim rst As dao.Recordset
Set rst = CurrentDb.OpenRecordset("Select * from [tempTable]")
For intCurrentRow = 0 To ctlSource.ListCount - 1
If ctlSource.Selected(intCurrentRow) Then
rst.AddNew
rst![field1] = Forms![myForm]![listbox1].Column(1, intCurrentRow)
rst![field2] = Forms![myForm]![listbox1].Column(0, intCurrentRow)
rst.Update
Forms![myForm]!listbox2.Requery
End If
Next intCurrentRow
Forms![myForm]!listbox2.Requery
done:
Exit Sub
nonrelation:
MsgBox Err.Description
End Sub
I know I have to use a 'resume' command somehow in place of my MsgBox Err.Description, but I've never used it. I would like to know how to properly implement that into my code. Thanks!

Answer 1

You could check if the record exists with a helper function and only add if not.
Public Function Exists(ByVal Value As String) As Boolean
Exists = DCount("*","tempTable","[field1]='" & Value & "'") > 0
End Function
Then inside your loop check each record before attempting to insert.
For intCurrentRow = 0 To ctlSource.ListCount - 1
If ctlSource.Selected(intCurrentRow) Then
If Not Exists(Forms![myForm]![listbox1].Column(1, intCurrentRow)) Then
With rst
.AddNew
![field1] = Forms![myForm]![listbox1].Column(1, intCurrentRow)
![field2] = Forms![myForm]![listbox1].Column(0, intCurrentRow)
.Update
End With
Forms![myForm]!listbox2.Requery
End If
End If
Next intCurrentRow
Note the above example expects a String. In case of a numeric, you will need to remove the ' ' quotes.