| Parents | Children | Properties | Methods | Events |
| Purpose: | Implements Multiple Document Interface (MDI) behaviour. |
Description
The multiple-document interface (MDI) is a document-oriented interface that is commonly used by word-processors, spreadsheets and other applications that deal with documents. An MDI application allows the user to display multiple documents at the same time, with each document displayed in its own window.
The MDIClient object is a container object that effectively specifies the client area within the parent Form in which the SubForm are displayed. The MDIClient object also imposes special MDI behaviour which is quite different from that where a SubForm is simply the child of another Form.
By default, the MDIClient occupies the entire client area within its parent Form. This is the area within the Form that is not occupied by CoolBars, MenuBars, ToolBars, ToolControls, TabBars, TabControls and StatusBars. In most applications it is therefore not necessary to specify the position and size of the MDIClient object, although you may do so if you want to reserve additional space in the parent Form for other objects.
Each of the four sides of an MDIClient object is automatically attached to the corresponding side of its parent Form and maintains its position when the parent Form is resized. This means that a default MDIClient always occupies the entire client area of its parent Form, regardless of how the parent is resized.
The appearance of the MDIClient may be changed using its Border, BCol and Picture properties. The EdgeStyle property has no direct effect and is provided only to pass on a value to its child Forms.
The MDIActive and MDIActiveObject properties contain the name of and a ref to the SubForm that currently has the focus. You may set these properties as well as query them.
You can call methods which cause the MDIClient to organise its child SubForms in some way. These methods are as follows:
| MDICascade | Causes the MDIClient to organise its child Forms in an overlapping manner. |
| MDITile | Causes the MDIClient to arrange its child Forms as a row or column. |
| MDIArrange | Causes the MDIClient to arrange the icons associated with any minimised child Forms in an orderly fashion. |