Preprocess

This event is sent before a user initiated action is processed.

void Preprocess(TejEvant ev)
{
   // example: Do something when the open toolbar button is clicked
   if (ev.ActionType = tej.ACTION_COMMAND 
                && ev.ActionId = tej.ID_OPEN) {
      ...
   }
}

The relevant TejEvent fields:

int ActionType:  Action Type
int ActionId: Action Id

The ActionType parameter can be one of the following:

ACTION_COMMAND:	This action indicates any of the menu or the accelerator key generated commands. The actual command id is given by the ActionId argument. For a list of command ids, please refer to the 'command' property in the Control Properties chapter.
ACTION_VSCROLL:	This action message is sent when the vertical scroll bar is clicked. The ActionId argument for this message identifies the actual scrollbar operation and is given by the SB_xxxxx SDK constants.
ACTION_HSCROLL	This action message is sent when the horizontal scroll bar is clicked. The ActionId argument for this message identifies the actual scrollbar operation and is given by the SB_xxxxx SDK constants.
ACTION_CHAR:	This action message is sent when the editor processes a WM_CHAR message. The ActionId argument for this message indicates the virtual key code for the key.
ACTION_LBUTTONDOWN	Left mouse button down. The ActionId contains the x and y mouse position in the pixel units. The x position is given by the low 16 bits and the y position is given by the high 16 bits.
ACTION_RBUTTONDOWN:	Right mouse button down. The ActionId parameter holds the mouse position as described for the ACTION_LBUTTONDOWN message.
ACTION_LBUTTONUP:	Left mouse button up. The ActionId parameter holds the mouse position as described for the ACTION_LBUTTONDOWN message.
ACTION_RBUTTONUP:	Right mouse button up. The ActionId parameter holds the mouse position as described for the ACTION_LBUTTONDOWN message.
ACTION_LBUTTONDBLCLICK:	Left mouse double click. The ActionId parameter holds the mouse position as described for the ACTION_LBUTTONDOWN message.
ACTION_RBUTTONDBLCLICK:	Right mouse double click. The ActionId parameter holds the mouse position as described for the ACTION_LBUTTONDOWN message.
ACTION_MOUSEMOVE:	Mouse move. The ActionId contains the x and y mouse position in the pixel units. The x position is given by the low 16 bits and the y position is given by the high 16 bits.
ACTION_SIZE:	Window being resized.
ACTION_SETFOCUS:	Tej window receiving focus.
ACTION_KILLFOCUS:	Tej window loosing focus.
ACTION_QUERYENDSESSION	This message is sent before asking the user to end the editing session.
ACTION_STYLE	This message is sent when the user selects a different style from the style combo-box. The ActionId specifies the selected style id.

ActionId: This value is specific to the action type as described above.