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Class (inherits from Object)

Any window. A window can be converted to a ContainerControl by changing its Super Class to ContainerControl. However, you cannot change the default window to a ContainerControl.

Activate DropObject MouseMove
CancelClose EnableMenuItems MouseUp
Close KeyDown MouseWheel
ConstructContextualMenu KeyUp Moved
ContentsChanged Maximize Open
ContextualMenuAction Minimize Paint
Deactivate MouseDown Resized
DragEnter MouseDrag Resizing
DragExit MouseEnter Restore
DragOver MouseExit ScaleFactorChanged
Backdrop HasFullScreenButton fa-lock-32.png MouseX fa-lock-32.png
BackgroundColor HasMaximizeButton fa-lock-32.png MouseY fa-lock-32.png
Bounds HasMinimizeButton fa-lock-32.png Resizeable fa-lock-32.png
Changed Height ScaleFactor fa-lock-32.png
ControlCount fa-lock-32.png ImplicitInstance SystemUIVisible
DefaultLocation Left Title
DockItem fa-lock-32.png MaximumHeight Top
Focus MaximumWidth TrueWindow fa-lock-32.png
FullScreen MenuBar Type fa-lock-32.png
Handle fa-lock-32.png MinimumHeight Visible
HasBackgroundColor MinimumWidth Width
HasCloseButton fa-lock-32.png MouseCursor
AcceptFileDrop DrawInto RefreshRect
AcceptPictureDrop FocusNext Restore
AcceptRawDataDrop FocusPrevious SetFocus
AcceptTextDrop Hide Show
BitmapForCaching Invalidate ShowModal
Close Maximize ShowModalWithin
Control Minimize ShowWithin
Controls Refresh UpdateNow

Class Constants

The following class constants of the DragItem class can be used to specify the value of the Action parameter of the DragEnter, DragExit, and DragOver events.

Class Constant Description
DragActionDefault Default action.
DragActionCopy Copy the dragged item.
DragActionMove Move the dragged item.
DragActionLink Link the dragged item.


Window constructors are called after the window and its controls are created, but before the Open events are called. If you are initializing Window properties, you should do so using the Open event handler rather than the Constructor. Using the Constructor could result in property changes you make being overwritten by the built-in Window initializations.

Understanding Sheet Windows

A "Sheet window" is the official name for drop-down dialog boxes that were introduced with macOS, where they often used in place of modal dialog boxes. Sheet windows behave as such only on OS X. On other platforms, they behave as ordinary movable modal dialog boxes.

A Sheet window behaves like a Modal dialog window, except that the animation makes it appear to drop down from the parent window's Title bar. It can't be moved from that position and it puts the user interface in a modal state. The user must respond to the choices presented in the Sheet window.

A Sheet window can be displayed by calling the ShowModalWithin method. If SheetWindow is defined as a Sheet window and MainWindow is a Document window, then the statement:


will show the Sheet window using the calling window (in this case, MainWindow) as the Parent window.

Note that the above works because SheetWindow has its ImplicitInstance property set to True.

You can also use your own instance like this:

Var sw As New SheetWindow

Custom Cursors

The MouseCursor property controls the appearance of the pointer when it is over the window, provided the MouseCursor property of the Application class is Nil. If you also want the pointer to change to another shape when it is over a control within the window, you must either assign the new value to the Window's MouseCursor property or temporarily set the window's MouseCursor property to Nil and the control's MouseCursor property to the desired cursor. See the section on the MouseCursor class for an example.

You can assign a MouseCursor using the library of cursors in the Cursors module.


This example sets the background color of the window to grey, provided the HasBackgroundColor property is set to True.

BackgroundColor = RGB(80, 80, 80)

This example increases the width of the window by 20 pixels.

Width = Width + 20

This example changes the title of the window.

Title = "Document 1"

The Resizing Event Handler

This example resizes three TextFields on the form in the Resizing event.The three TextFields are aligned horizontally. As the user stretches or shrinks the window, the TextFields' widths change proportionally.

Var availableSpace As Integer
Var field1Size, field2Size, field3Size As Integer

// subtract 40 pixels for the space between the
// three fields and on left and right side of the window
availableSpace = Me.Width - 40

// calculate the size of each field based on a percentage
field1Size = availableSpace * 0.6 // 60 percent
field2Size = availableSpace * 0.3 // 30 percent
field3Size = availableSpace * 0.1 // 10 percent

// Set the field widths
TextField1.Width = field1Size
TextField2.Width = field2Size
TextField3.Width = field3Size

// reposition the fields based on the new sizes
TextField2.Left = TextField1.Left + TextField1.Width + 10
TextField3.Left = TextField2.Left + TextField2.Width + 10

Contextual Menu Example

The following example shows how to present and handle a contextual menu in a window using the ConstructContextualMenu and ContextualMenuAction event handlers.

The following code in a ConstructContextualMenu event builds a simple contextual menu. The parameter base (a MenuItem) is passed in as a parameter and you add your contextual menu to it:

base.Add(New MenuItem("Import"))
base.Add(New MenuItem("Export"))
Return True // display the contextual menu

The following Select statement in the ContextualMenuAction event handler inspects the selected menu item, which is passed in as the selectedItem (a MenuItem) parameter.

Select Case selectedItem.Text
Case "Import"
MessageBox("You chose Import")
Case "Export"
MessageBox("You chose export")
End Select

Return True

DrawInto Example

This example draws the contents of a window into a Graphics object. For example, add a second window to a new project (Window2) and set its Visible property to False. Add a variety of controls to Window2. In the Paint event of Window1, use this code to draw the second window into the first window:

Window2.DrawInto(g, 0, 0)

The contents of Window2 are drawn into Window1.

Accessing Controls and Properties in Other Windows

When changing a window property from another window, there are two possible approaches you can take. If you have only one instance of the window you need to reference, you can use the window's object name as a reference. For example, if you had a window called window1 that had a TextField called TextField1 and you wanted to assign the value "Fred" to the text property of that TextField, you would using the following syntax:

Window1.TextField1.Value = "Fred"

If you have multiple instances of the same window class open at the same time, then a reference to the target window must be included as in this example where a new window is opened and its window title changed. "anotherWindow" is a window class in the Project.

Var w As AnotherWindow
w = New AnotherWindow
w.Title = "Your Results"

Handling Drag and Drop

For an explanation of handling drag and drop, see the Control class and the DragItem class.

See Also

Window function; MessageDialog class.