TMDI* (MDI Classes)

Sources: source/classes/mdiframe.prg, mdiclien.prg, mdichild.prg

All three inherit from: TWindow

The MDI (Multiple Document Interface) system consists of three coordinated classes: TMDIFrame (the main frame window), TMDIClient (the client area that manages child windows), and TMDIChild (individual document child windows). Together they provide the classic Windows MDI experience with tiling, cascading, icon arrangement, and menu merging.

TMDIFrame DATA Members

DATA	Type	Description
`oWndClient`	Object	The TMDIClient object that manages child windows
`oWndActive`	Object	Reference to the currently active MDI child window
`oMenu`	Object	Menu object attached to the frame; "Window" submenu is auto-managed
`lChildAutoSize`	Logical	Auto-maximize new child windows to fill the client area

TMDIClient DATA Members

DATA	Type	Description
`aWnd`	Array	Array of all TMDIChild windows managed by this client

TMDIChild DATA Members

DATA	Type	Description
`oWndClient`	Object	Reference to the parent TMDIClient
`oControl`	Object	Optional active control for clipboard/EDIT forwarding

Methods

Class	Method	Description
TMDIFrame	`New( nTop, nLeft, nBottom, nRight, cTitle, nStyle, oMenu, oBrush, oIcon, ... )`	Create the MDI frame window
TMDIFrame	`ChildNew( ... )`	Create a new MDI child window
TMDIFrame	`Cascade() / Tile( lHor ) / ArrangeIcons()`	Arrange child windows
TMDIFrame	`CloseAll() / CloseActive()`	Close all or the active child
TMDIFrame	`NextWindow() / PrevWindow()`	Cycle through child windows
TMDIFrame	`Zoom()`	Maximize the active child
TMDIFrame	`SetMenu( oMenu, nMenuInfo )`	Set the frame menu with MDI window submenu tracking
TMDIClient	`New( oFrame, nSubMenu, nIdChildFirst, oBrush, ... )`	Create the MDI client window
TMDIClient	`GetActive()`	Return the currently active child window (or nil)
TMDIClient	`ChildNew( ... )`	Create and activate a new MDI child
TMDIClient	`ChildClose( oWnd )`	Close a specific child window
TMDIClient	`Tile( lHor ) / Cascade() / ArrangeIcons()`	Arrange child windows within the client
TMDIChild	`New( nTop, nLeft, nBottom, nRight, cTitle, nStyle, oMenu, oWnd, ... )`	Create a new MDI child window
TMDIChild	`Activate()`	Show and activate the child window
TMDIChild	`Maximize() / Restore() / Minimize()`	Window state management
TMDIChild	`SetControl( oCtrl )`	Associate an active control (e.g., for clipboard forwarding)

Example: MDI Frame with Two Child Windows

#include "FiveWin.ch"

function Main()

   local oWnd, oChild1, oChild2

   DEFINE MDIFRAME oWnd TITLE "MDI Demo"

   DEFINE MDICHILD oChild1 TITLE "Document 1" OF oWnd
   @ 10, 10 SAY "First document" OF oChild1

   DEFINE MDICHILD oChild2 TITLE "Document 2" OF oWnd
   @ 10, 10 SAY "Second document" OF oChild2

   ACTIVATE MDIFRAME oWnd MAXIMIZED

return nil

Notes

Use DEFINE MDIFRAME ... TITLE cTitle to create the frame. The frame automatically creates a TMDIClient and adds a "Window" submenu for child management if none is provided.
Use DEFINE MDICHILD oChild OF oWnd TITLE cTitle to create child windows. They are automatically registered with the TMDIClient via Add().
TMDIFrame forwards clipboard operations (Copy, Cut, Paste, Undo, Redo, Find, SelectAll) to the active child's active control.
Menu merging: when the frame is created with a menu, the nMenuInfo parameter specifies which submenu position becomes the Window list.
The lChildAutoSize flag on TMDIFrame causes new children to open maximized.