I have a form with buttons that I'd like to disable after they are pushed, like the save and the undo buttons, and then re-enable them after the data on the form is changed. When the user pushes either of these buttons, they receive the focus so I can't diable them while they have the focus. Instead of just sending the focus back to the first data field control, I implemented a "last active control" mechanism using a global variable of control type and the exit event's of the data entry fields.

When either of these buttons is pushed, I'm sending the focus back to the control stored in the global variable with the statement:

        Last_Active_Control.setfocus

This works well most of the time, but sometimes I am told that the assignment isn't valid, especially during debugging. Is there a way to check that the global variable has been assigned a valid control before making the trying to use it to set the focus?

Unfortunately, there doesn't seem to be an IsControl test in Access 2000's vba.

Thank you.

What assignment is in the global variable when you are being told it isn't valid? What does the variable look like when it is valid?



mmcdonal

When the form is opened, I assign the first combobox on the form to the global variable, then in each of the exit events of the enabled field controls, i.e., not the Save or Undo buttons, I update the global variable to the control that the user is exiting. The problem seems to occur after the degugger is invoked, but I'd really like to test the global veriable before I try to do a setfocus on it. The problem is I don't know how to test the global variable of control type to see if it is valid.

I created the global variable as:

    Dim Last_Active_Control As Control

I assign the global as:

    Last_Active_Control = Me.Unbound_Field_Control

I finally figure out how to test the value of a control type variable.

You can't simply test using:

  If Ctrl = Nothing ...

You need to use:

  If Ctrl Is Nothing ...
     or
  If Ctrl Is Not Nothing ...

So now I can test my global control variable before attempting to set the focus to it.