vbYesNo MsgBox problem

>If iAnswer = True Then
needs to be
If iAnswer = vbYes Then

Yes No buttons do not provide True/False values.

Use vbYes to test for Yes and vbNo to test for No.

Thanks that works, but I cant figure out why the code is not performing on pressing yes, the first time and the second time. However, if both the criteria are satisfied and the user does not need to use the YesNo button then the primary Object Form opens. Can you help please:

Private Sub Arthur_ID_DblClick(Cancel As Integer)
Dim iAnswer As Integer
Dim iAnswer1 As Integer

On Error GoTo Err_Arthur_ID_DblClick
If IsNull(Me.Parent!Contract_End_date) Then
iAnswer = MsgBox("You cannot Calculate Introduction Discount when the Introducing Patient's Contract End Date has not been filled. Do You want to add this information first?", vbYesNo)
ElseIf iAnswer = vbYes Then
EditIntroducingPtContractStartDate        '''This is the subroutine shown below
ElseIf IsNull(Me.[Introduced pt Contract Start Date]) Then
iAnswer1 = MsgBox("You cannot Calculate Introduction Discount when the Introduced Patient's Contract End Date has not been filled. Do You want to add this information first?", vbYesNo)
ElseIf iAnswer1 = vbYes Then
EditIntroducedPtContractStartDate     '''This is another subroutine shown below
Else: OpenThisForm    '''This is the destination form that is the primary object of the Command
End If
End Sub

Private Sub EditIntroducingPtContractStartDate()
Dim stDocName As String
    Dim StLinkCriteria As String
   
    stDocName = "Fo_main_Patient_List1"
   
    StLinkCriteria = "[Main_Pt_ID]=" & Me.Parent![Main_Pt_ID]
   
   DoCmd.OpenForm stDocName, , , StLinkCriteria
    End Sub


Private Sub EditIntroducedPtContractStartDate()

Dim stDocName As String
    Dim StLinkCriteria As String
   
    stDocName = "Fo_main_Patient_List1"
   
    StLinkCriteria = "[Main_Pt_ID]=" & Me.[introduced Pt ID]
   
    DoCmd.OpenForm stDocName, , , StLinkCriteria
   

End Sub

Private Sub OpenThisForm()


    Dim stDocName As String
    Dim StLinkCriteria As String

    stDocName = "Fo_Introductions_Line_ItemA"
   
    StLinkCriteria = "[Introduced Pt ID]=" & Me![introduced Pt ID]
    DoCmd.OpenForm stDocName, , , StLinkCriteria

End Sub

This is how one learns thanks to you guys. Big Improvement LamberHeenan, but what the code is doing is that if the user clicks No for both the questions, it opens the final form (the object of the command)form which I dont want. I want it to exit if the details are not rectified. I tried to modify your VBA to do this but its not 100%. My objective is:

1. If date 1 is null  - Question 1. Yes - Gotoform to rectify and exit sub
                                Question 1. no - Exit Sub

2. If date 2 is null - Question 2 Yes - Goto Form to rectify and exit sub
                               Question 2. No - Exit sub

Open Object Form (This implies that neither of the date fields were null)

My modification of your code is this. What it is not doing is:
(a) If question 1 is No, it is going to question 2 without exiting
(b) The MsgBox apears twice with the Yes?No question when first time round one selects No

Can you possibly help me to rectify it:

The Code:

Private Sub Arthur_ID_DblClick(Cancel As Integer)

Const MSG_Parent = "You cannot Calculate Introduction Discount when the Introducing Patient's Contract End Date has not been filled. Do You want to add this information first?"

Const MSG_Me = "You cannot Calculate Introduction Discount when the Introduced Patient's Contract Start Date has not been filled. Do You want to add this information first?"

On Error GoTo Err_Arthur_ID_DblClick

' Check the date on the parent form
If IsNull(Me.Parent!Contract_End_date) Then
    If MsgBox(MSG_Parent, vbYesNo) = vbYes Then
        EditIntroducingPtContractStartDate
        Exit Sub
    ElseIf MsgBox(MSG_Parent, vbYesNo) = vbNo Then
    Exit Sub
        '''Else: Exit Sub
    End If
End If

' Check the date on the current form. Note you do not need to use Me
' in order to access the date field as it's part of the namespace of the form

If IsNull([Introduced pt Contract Start Date]) Then
    If MsgBox(MSG_Me, vbYesNo) = vbYes Then
        EditIntroducedPtContractStartDate
        Exit Sub
    ElseIf MsgBox(MSG_Me, vbYesNo) = vbNo Then
        Exit Sub
    '''If IsNull(Me.Parent!Contract_End_date) = False Then
'''If Me.[Introduced pt Contract Start Date] = False Then

End If
End If

OpenThisForm   '''This is the destination form that is the primary object of the Command

Exit_Arthur_ID_DblClick:
    Exit Sub

Err_Arthur_ID_DblClick:
    MsgBox Err.Description
    Resume Exit_Arthur_ID_DblClick
   
   
End Sub

Very detailed effort, particularly by LambertHeenan, and I learnt a lot from it, but the solution was imperfect and I did not receive a feedback for this on enquiring about it.

Oops I missed the step that handles their answering 'No' This should handle that...

Private Sub Arthur_ID_DblClick(Cancel As Integer)

Const MSG_Parent = "You cannot Calculate Introduction Discount when the Introducing Patient's Contract End Date has not been filled. Do You want to add this information first?"

Const MSG_Me = "You cannot Calculate Introduction Discount when the Introduced Patient's Contract End Date has not been filled. Do You want to add this information first?"

On Error GoTo Err_Arthur_ID_DblClick ' need to define the error handler!

' Check the date on the parent form
If IsNull(Me.Parent!Contract_End_date) Then
    If MsgBox(MSG_Parent, vbYesNo) = vbYes Then
        EditIntroducingPtContractStartDate      
        If IsNull(Me.Parent!Contract_End_date) Then Exit Sub
    Else
       Exit Sub ' they answered No
    End If
End If

' Check the date on the current form. Note you do not need to use Me
' in order to access the date field as it's part of the namespace of the form

If IsNull([Introduced pt Contract Start Date]) Then
    If MsgBox(MSG_Me, vbYesNo) = vbYes Then
        EditIntroducedPtContractStartDate
        If IsNull([Introduced pt Contract Start Date]) Then Exit Sub
    Else
       Exit Sub ' they answered No
    End If
End If

OpenThisForm    '''This is the destination form that is the primary object of the Command

Exit Sub
Err_Arthur_ID_DblClick:
    ' your error handler code here
End Sub


Notice how the logic works here.

If DATE_IS_NULL Then
  If UserWantsToEdit Then ' MsgBox call
       EditTheDate
       If Date still Null Then Exit Sub
  Else
       Exit Sub ' Abandon the whole process - user said No
   End If
End If

and then repeat the exact same logic for the other date field.

In your latest version posted you did something a bit different...

10  If IsNull(Me.Parent!Contract_End_date) Then
20    If MsgBox(MSG_Parent, vbYesNo) = vbYes Then
30        EditIntroducingPtContractStartDate
40        Exit Sub
50    ElseIf MsgBox(MSG_Parent, vbYesNo) = vbNo Then
60    Exit Sub
70        '''Else: Exit Sub
80    End If
90 End If


Line 20 asks the question and if the use says Yes we go off and edit on line 30

But then line 40 exits the sub routine. This forces the user to double click on the form control again, which is not necessary.

Line 40 has the effect that if they answer No to the first MsgBox prompt they will be asked the exact same question again, and if they still answer No then exit sub. But if the answer Yes... nothing is done. We just step out of the If statement block.

When you code


If MsgBox(MSG_Parent, vbYesNo) = vbYes Then

there are only two possible return values for MsgBox, vbYes or vbNo. If (in line 20) the result is not vbYes it *must* be vbNo, so you can code
If MsgBox(MSG_Parent, vbYesNo) = vbYes Then
   ' do something
Else
    Exit Sub
End If

...and not...

ElseIf  MsgBox(MSG_Parent, vbYesNo) = vbNo Then

... which repeats the question already answered, becuase you called MsgBox again. At the risk of boring you with repetition, the logic should be...

If PARENT FORM DATE_IS_NULL Then
  If MSgbox = vbYes Then
' the next two lines execute if the user responds with Yes
       EditTheDate
       If Date still Null Then Exit Sub
  Else
' otherwise this line executes - they answered No
       Exit Sub ' Abandon the whole process
   End If
End If

' followed directly by ...

If SUB_FORM_DATE_IS_NULL Then
    If MSgbox = vbYes Then
       EditTheDate
       If Date still Null Then Exit Sub
    Else
       Exit Sub ' Abandon the whole process
    End If
End If

' now we have two dates we can call the final process
OpenThisForm  

Lambert

Fantastic Mr. Expert...Logic issues can be a work of art in good hands...LOL (: