How to prevent duplicate data entry in a text box??

Hi I have a simple form for data entry, the MDB file contains 4 fields, and I have a form with 4 text boxes bounded to the MDB file. My question is how do I prevent a duplicate entry on the text box??

I have a simple procedure but it gives me runtime error 3426 ??

' After entering data hit the check_duplicate button to
' check for duplicate entry
Private Sub CheckDuplicateButton_Click()
    strBookmark = ContractData.Recordset.Bookmark
    ' CQuote is the textbox name which bound to the MDB file field [Quote #]
    strCriterion = "[Quote #]= '" & UCase(CQuote) & "'"

    ContractData.Recordset.FindFirst strCriterion
    If ContractData.Recordset.NoMatch Then
        ContractData.Recordset.Bookmark = strBookmark
    Else
        MsgBox ("Duplicate Contract # Entry!!")
    End If
End Sub

If I enter a quote# which previously exist it gives me runtime error 3426??

Any idea from you guys or any better way?? Oh I am using VB4.0.


Thanks
wyanAsked:
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y96andhaCommented:
On what line do you get error 3426?
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vorlonCommented:
What is error 3426? (Don't have a reference next to me, sorry)
0
y96andhaCommented:
Error 3426 is "The action was canceled by an associated object."

You said in your question that you got it when you entered something that already exists.
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y96andhaCommented:
Runtime error 3426 should have something to do with calling the update method without an edit or addnew. Are you sure you haven't made an edit earlier, and then when you move to another record and back, it is lost, and when you try update the error 3426 appears?
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mikekrCommented:
I don't know what an error 3426 is, but the easiest way to prevent dupilcate data is to set the index property of each field in the table to Yes(No Duplicates)... If your text fields on the form are bound to a data contol, when the data control updates the data in the table, and error will be returned... I can't remember the error number, but I'm sure you'll be able to work it out. You can then trap the error at run time, and use code to deal with the error.
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Visual Basic Classic

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