Message box for null fields - vba

Question

I am trying to create a database for part locations. Three of the fields (JobNumber, PartNumber and Location) are required fields and I have an If statement written to check for Nulls and error handling to give a message box. After the message box is closed, it will let me return to the form but it will not allow me to edit the field again AND it still adds the incomplete data to the table. Any advice?
Private Sub cmdAddNew_Click()
If IsNull(Me.JobNumber) Then
GoTo cmdAddNew_Click_Err
ElseIf IsNull(Me.PartNumber) Then
GoTo cmdAddNew_Click_Err
ElseIf IsNull(Me.Location) Then
GoTo cmdAddNew_Click_Err
End If
On Error GoTo cmdAddNew_Click_Err
On Error Resume Next
DoCmd.GoToRecord , "", acNewRec
If (MacroError <> 0) Then
Beep
MsgBox MacroError.Description, vbOKOnly, ""
End If
cmdAddNew_Click_Exit:
Exit Sub
cmdAddNew_Click_Err:
MsgBox "Job Number, Part Number and Location are required."
End Sub

Answer 1

Adding Cancel = True in your second if statement should fix this.
Private Sub cmdAddNew_Click()
If IsNull(Me.JobNumber) Then
GoTo cmdAddNew_Click_Err
ElseIf IsNull(Me.PartNumber) Then
GoTo cmdAddNew_Click_Err
ElseIf IsNull(Me.Location) Then
GoTo cmdAddNew_Click_Err
End If
On Error GoTo cmdAddNew_Click_Err
On Error Resume Next
DoCmd.GoToRecord , "", acNewRec
If (MacroError <> 0) Then
Beep
MsgBox MacroError.Description, vbOKOnly, ""
Cancel = True
End If
cmdAddNew_Click_Exit:
Exit Sub
cmdAddNew_Click_Err:
MsgBox "Job Number, Part Number and Location are required."
End Sub
Alternatively, you could define functions to check for a null value and return a boolean result:
Function isvalid(Field as string) As Boolean
If IsNull(field)
isvalid = False
Else
isvalid = True
End If
End Function
Sub Check_valid()
Call isvalid(field 1)
Call isvalid(f2)
Call isvalid(f3)
If isvalid(field 1) = false Or isvalid(f2) = false Or isvalid(f3) = false Then
msgbox "Job Number, Part Number and Location are required."
Exit Sub
End If
End Sub
Hope this helps!