Data Validation

[cwby1966]

I am Trying to validate information entered into 4 fields on a form. They can not be empty. If one of the fields is empty then the code should give a message athen stop. If all fields are valid then it should continue. I have listed the code below, can some give direction.
[code]
Private Sub GetProjid_Click()
If Forms![frm_proj log]![site id] = "" Then
MsgBox "You have not selected a Location. " & _
"Please Correct This error and resubmit.", vbOKOnly, "Validation Error"
DoCmd.GoToControl "Forms![frm_proj log]![site id]"
Cancel = 1
End If
If Forms![frm_proj log]![Project Title] = "" Then
MsgBox "You have entered a Project Title. " & _
"Please Correct This error and resubmit.", vbOKOnly, "Validation Error"
DoCmd.GoToControl "Forms![frm_proj log]![Project Title]"
Cancel = 1
End If
If Forms![frm_proj log]![Description] = "" Then
MsgBox "You have not entered a Project Description. " & _
"Please Correct This error and resubmit.", vbOKOnly, "Validation Error"
DoCmd.GoToControl "Forms![frm_proj log]![Description]"
Cancel = 1
End If
If Forms![frm_proj log]![Proj# Sponsor] = "" Then
MsgBox "You have not Entered a Project Sponsor. " & _
"Please Correct This error and resubmit.", vbOKOnly, "Validation Error"
DoCmd.GoToControl "Forms![frm_proj log]![Proj# Sponsor]"
Cancel = 1
End If
Forms![frm_proj log]![Project ID] = Forms![frm_proj log]![site id] & "-" & IIf(Forms![frm_proj log]!mth _
< 10, "0" & Forms![frm_proj log]!mth, Forms![frm_proj log]!mth) & IIf(Forms![frm_proj log]!day _
< 10, "0" & Forms![frm_proj log]!day, Forms![frm_proj log]!day) & Forms![frm_proj log]!year & "-" & IIf(Forms![frm_proj log]![Record # fixed] < 10, "0" & Forms![frm_proj log]![Record # fixed], Forms![frm_proj log]![Record # fixed])
Me!New = "no"

End Sub
[code]
Thanks

[ADezii]

I modified only the relevant (Validation) portion of the code segment which should go in the BeforeUpdate() Event of the Form:

Private Sub Form_BeforeUpdate(Cancel As Integer)
If IsNull(Me![site id]) Then
  MsgBox "You have not selected a Location. " & _
         "Please Correct This error and resubmit.", vbOKOnly, "Validation Error"
           Me![site id].SetFocus
             Cancel = True
ElseIf IsNull(Me![Project Title]) Then
  MsgBox "You have entered a Project Title. " & _
         "Please Correct This error and resubmit.", vbOKOnly, "Validation Error"
           Me![Project Title].SetFocus
             Cancel = True
ElseIf IsNull(Me![Description]) Then
  MsgBox "You have not entered a Project Description. " & _
         "Please Correct This error and resubmit.", vbOKOnly, "Validation Error"
           Me![Description].SetFocus
             Cancel = True
ElseIf IsNull(Me![Proj# Sponsor]) Then
  MsgBox "You have not Entered a Project Sponsor. " & _
         "Please Correct This error and resubmit.", vbOKOnly, "Validation Error"
           Me![Proj# Sponsor].SetFocus
             Cancel = True
End If
 
'Drop through and resume Normal processing/Updating here
End Sub