Question : Access Form Validation

Hi

I have a simple Access form that is linked to a table.
The user can enter a new record simply by typing into the form as they would
into a table.
I need to do certain validation checks but am not sure where to put the code
Should it be in the before update event?
What code do I write to prevent the update occurring.
Thanks

Answer : Access Form Validation

You can either put validation code in the Form_BeforeUpdate event to validate the entire form, but I much prefer to treat each control in it's own right by placing validation code in each individual control's BeforeUpdate event.

The kind of code you put there will depend on the (expected) data type and range of the underlying data; e.g.

Private Sub txtFirstName_BeforeUpdate(Cancel As Integer)

if(txtFirstName.Text & vbNullString = vbNullString) Then
   MsgBox "Firstname is required!", vbOkOnly
  Cancel = True
  txtFirstName.Undo
End if

End Sub

Alternatively, a very effective way to handle data validation is to use the underlying Table's Validation Rule and Validation Text properties for the field to be validated; e.g.

Table tbl_person_data

Firstname Text(20)
Validation Rule (Is Not Null) And (<> "")
Validation Text "Firstname is a required field"

DateOfBirth Date/Time
Validation Rule (> #01-Jan-1930#) and (< Now())
Validation Text "Date of Birth cannot refer to a date in the future" etc.

NumberOfChildren Integer
Validation Rule (>=0) And (<=10)
Validation Text "System cannot cope with less than 0, or more than 10 children"

RangeOfNumbers
Validation Rule IN(2,3,4,5,6,7)
Validation Text "Number range outside acceptable range (should be in the range 2-7 inclusive)"