CODEWITHSUNDEEP
ms-accessvbams-access-2010
Justin
Justin

Reputation: 972

Differences in referencing forms in VBA Access

Intro:

I have two separate forms.

  1. frmABC
  2. frmXYZ

I have frmABC in focus and I run a procedure that will "Tick" a checkbox called ChkConfirmed on frmXYZ.

Question:

What is the difference between these two ways of referencing another form?

1. Form_frmXYZ.ChkConfirmed = True

2. Forms!frmXYZ.ChkConfirmed = True

For some reason, only #2 works in this scenario. For me this is bewildering purely beacuse I have always used #1 and it has never complained before (when I say complain, I mean it does the job).

But, when I use #1 here and step through the code, it definitely runs the code but does not check any boxes...just nothing.

So, I would love to know the technical differences to help me understand when to use each one and in what cases.

EDIT: Actual code snippet (as requested)

#1 Version

enter image description here

#2 Version

enter image description here

Upvotes: 2

Views: 1014

Answers (2)

Krish
Krish

Reputation: 5917

Access (I think >=97) treats Forms as a Class which means your forms are now a class module and can have all [class behaviors] including instancing.

Form_your_formname: you are referencing the Form via the Class module.

Forms!your_form name: You are referencing the form by its form name.

To access a form via Forms!form_name, the form must already have been loaded. Otherwise the form won't be reachable and you will get an error message "the referenced ...... not found"

On the other hand, Form_form_name can be accessed at any time as a class. It can have multiple instances like all classes do. Accessing an unopened form via its class module will cause the form is being instanced. This means Access will create a new hidden instance of that Form.

To test this try following.

  1. Create a new form called: frm_test with a text box in it called: txt_id
  2. go to your immediate window and try following code:
  3. Edit forgot to mention. The test form hast to have a vba module attached to it then only it becomes a class module

Form_frm_test.txt_id = 1 Form_frm_test.visible = true ?Form_frm_test.hwnd docmd.openform "frm_test" ?Forms!frm_test.hwnd

Now you will see two instance of the frm_test form and each of them will have their own window handle.

to answer your question:

  1. But, when I use #1 here and step through the code, it definitely runs the code but does not check any boxes...just nothing.

    its because your form is being instanced and its hidden.

  2. So, I would love to know the technical differences to help me understand when to use each one and in what cases.

    Technical explanation given above. if your form is already loaded you can use the Form!form_name / form_name to access it. If you are instancing use the class name.

Upvotes: 4

Gene
Gene

Reputation: 392

To be honest, I've never seen your 1st example used, ever... In fact a quick test in Access 2010 fails with an "Object Required" error message. All the code I've ever done uses the exclamation, which (someone correct me if I'm worng) works in all circumstances where you would need to reference another form for something.

Upvotes: -2

Related Questions