OPTION Explicit

FUNCTION ffnValidTimeDate (vTime2Check AS Variant, dynDataSet AS Dynaset, zFieldNameToCheck AS STRING, fSayMessage AS INTEGER) AS INTEGER
' Returns true if time value is valid.

    ' Data expected:
    ' vTime2Check has time to validate
    ' dynDataSet is the dynaset we will use to validate the date
    ' zFieldNameToCheck is the name of the dynaset field we will use to test the date
    ' If fSayMessage is true display a message
   
    ' This function uses the database itself to validate the date.
    ' A clone of the incomming dynaset is used so that the record pointer of
    ' the original dynaset is not disturbed.
   
    DIM dynDynasetClone AS Dynaset
    DIM zMsgText AS STRING

    Set dynDynasetClone = dynDataSet.Clone()

    ' the function only returns false if an error is triggered.
    ffnValidTimeDate = True
   
    dynDynasetClone.AddNew
   
    ON ERROR GOTO ErrorffnValidTimeDate
   
    ' Attempt to set the date field to the date supplied to the function.
    ' An error indicates that the date was not valid.

    dynDynasetClone.Fields(zFieldNameToCheck) = vTime2Check
   
    ON ERROR GOTO 0
   
    ' a second addnew clears the new record buffer
    dynDynasetClone.AddNew
   
    ' because the close occurs without an update, no new records will be added.
    dynDynasetClone.CLOSE

    Set dynDynasetClone = Nothing
       
    GOTO ExitffnValidTimeDate

ErrorffnValidTimeDate:

    ffnValidTimeDate = False
   
    IF fSayMessage = True THEN
        IF ERR = 13 THEN
            ' Err 13 is a type mismatch error
            zMsgText = "The date you entered does not appear to be correct.  "
            zMsgText = zMsgText & "Please try again."
        ELSE
            ' Always a good idea to provide for the unknown
            zMsgText = "An unexpected error occur while validating the date.  "
            zMsgText = zMsgText & "Please try again."
        END IF
    END IF
   
    MsgBox zMsgText
   
    RESUME NEXT

ExitffnValidTimeDate:

END FUNCTION

SUB Main ()
   
    Load Form1

    Form1!Data1.DatabaseName = app.Path + "\" + "valdate.mdb"
    Form1!Data1.RecordSource = "Invoices"
    Form1!Text2.DataField = "ShipDate"
    Form1!Text1.DataField = "InvoiceNumber"
    Form1!Text3.DataField = "CustomerID"

    Form1.Show

END SUB