Function RunSum(F As Form, KeyName As String, KeyValue, _
FieldToSum As String)
'***********************************************************
' FUNCTION: RunSum()
' PURPOSE: Compute a running sum on a form.
' PARAMETERS:
' F - The form containing the previous value to
' retrieve.
' KeyName - The name of the form's unique key field.
' KeyValue - The current record's key value.
' FieldToSum - The name of the field in the previous
' record containing the value to retrieve.
' RETURNS: A running sum of the field FieldToSum.
' EXAMPLE: =RunSum(Form,"ID",[ID],"Amount")
'***********************************************************
Dim rs As Recordset
Dim result
On Error GoTo Err_RunSum
' Get the form Recordset.
Set rs = F.RecordsetClone
' Find the current record.
Select Case rs.Fields(KeyName).Type
' Find using numeric data type key value?
Case DB_INTEGER, DB_LONG, DB_CURRENCY, _
DB_SINGLE, DB_DOUBLE, DB_BYTE
rs.FindFirst "[" & KeyName & "] = " & KeyValue
' Find using date data type key value?
Case DB_DATE
rs.FindFirst "[" & KeyName & "] = #" & KeyValue & "#"
' Find using text data type key value?
Case DB_TEXT
rs.FindFirst "[" & KeyName & "] = '" & KeyValue & "'"
Case Else
MsgBox "ERROR: Invalid key field data type!"
GoTo Bye_RunSum
End Select
' Compute the running sum.
Do Until rs.BOF
result = Round2CB(result + rs(FieldToSum))
' Move to the previous record.
rs.MovePrevious
Loop
Bye_RunSum:
RunSum = result
Exit Function
Err_RunSum:
Resume Bye_RunSum
End Function
