How to Use Data Sessions in a Toolbar to Show Changes (131017)

MORE INFORMATION

The main reason the DataSessionID property is read/write is so you can set non-databound forms or toolbars to link up with another private data session's form, formset, or toolbar. The toolbar can query the _Screen.Activeform property to determine which form is currently active. Each form can have a property identifying whether it's in the process of an edit or not.

Method One

Make sure the toolbox class has DataSessions=2. Then within a method of a toolbox subclass, try the following logic to manipulate data of the active form:

   Thisform.DataSessionID=_screen.ActiveForm.DataSessionID
				

Method Two

Use a timer to determine the status of the active form, enabling or disabling controls on the toolbar as appropriate. In the toolbar's INIT event, add a Timer to the screen as follows:

   _Screen.AddObject("ToolBartimer" MyTimerClass)
				

If you want the toolbar and the form to share data sessions, place the following code in the Timer event method:

   MyToolBar.DataSessionID = IIF(TYPE("_Screen.ActiveForm") == "O",;
      _Screen.ActiveForm.DataSessionID,1)
				

In the Timer event code, use the GETFLDSTATE(-1) function to determine if the data on the active form has been changed or deleted as in this example code:

IF ( ("2" $ GETFLDSTATE(-1)) OR ;
     ("3" $ GETFLDSTATE(-1)) OR ;
     ("4" $ GETFLDSTATE(-1)) )
   MyToolBar.cmdNewButton.Enabled  = .F.
   MyToolBar.cmdSaveButton.Enabled = .T.
   MyToolBar.cmdUndoButton.Enabled = .T.
ELSE
   MyToolBar.cmdNewButton.Enabled  = .T.
   MyToolBar.cmdSaveButton.Enabled = .F.
   MyToolBar.cmdUndoButton.Enabled = .F.
ENDIF
				

NOTE: Make sure your toolbar does not contain any bound controls. Changing the datasession of a bound form is not recommended.