The EDITSTATECHANGED event

One of the requirements we needed when developing the new IDE was the ability to detect when the state of a control changed in such a fashion that might affect the operations that could be performed on it. A classic example of this is highlighting text in an edit control so that it can be cut or copied, or perhaps replaced with a paste operation: At this point an item like a Cut or a Paste button might need enabling so the UI is in sync with the state of the control. To enable this functionality several controls now support a new event called EDITSTATECHANGED, which is fired when the "edit state" is changed.  The edit state is defined as one of the following operations:

• Undo
• Redo
• Cut
• Copy
• Paste
• Select All

So, if a user takes an action in the control that enables or disables one of these options you can respond to it via the EDITSTATECHANGED event. The EDITSTATECHANGED event passes a single parameter called "EditState", which is a dynamic array of Boolean flags with the following structure:

<1> CanUndo      : TRUE$ if the control allows an UNDO operation
<2> CanRedo      : TRUE$ if the control allows a REDO operation
<3> CanCut       : TRUE$ if the control allows a CUT operation
<4> CanCopy      : TRUE$ if the control allows a COPY operation
<5> CanPaste     : TRUE$ if the control allows a PASTE operation
<6> CanSelectAll : TRUE$ if the control allows a SELECTALL 
                 : operation

(You may notice that these flags closely follow the items in a standard "Edit" menu). Here's a simple example to set the state of some Cut/Copy/Paste buttons:

   objxArray =        @window : ".BTN_CUT"
   propArray =        "ENABLED"
   dataArray =        editState<0,3>

   objxArray := @rm : @window : ".BTN_COPY"
   propArray := @rm : "ENABLED"
   dataArray := @rm : editState<0,4>
   
   objxArray := @rm : @window : ".BTN_PASTE"
   propArray := @rm : "ENABLED"
   dataArray := @rm : editState<0,5>

   call Set_Property_Only( objxArray, propArray, dataArray )

The following controls support the EDITSTATECHANGED event:

• COMBOBOX
• EDITLINE
• EDITBOX
• EDITTABLE
• LISTBOX
• PROPERTYGRID

(Disclaimer: This article is based on preliminary information and may be subject to change in the final release version of OpenInsight 10). (EDIT: 8th May 2018 - Variable name changed from NewEditState to EditState to match released version)