Common Properties, Events, and Methods

Every control in DVX BASIC inherits a set of common properties, events, and methods. These are handled by the form runtime before dispatching to widget-specific interface descriptors.

Common Properties

  Property     Type      R/W   Description
  ----------   -------   ---   -------------------------------------------
  Name         String    R     The control's name (e.g. "Command1"). Read-only at runtime.
  Left         Integer   R/W   X position in pixels relative to the parent container.
  Top          Integer   R/W   Y position in pixels relative to the parent container.
  Width        Integer   R/W   Current width in pixels. Setting this changes the minimum width constraint.
  Height       Integer   R/W   Current height in pixels. Setting this changes the minimum height constraint.
  MinWidth     Integer   R/W   Minimum width for layout. Alias for Width in the setter.
  MinHeight    Integer   R/W   Minimum height for layout. Alias for Height in the setter.
  MaxWidth     Integer   R/W   Maximum width cap (0 = no limit, stretch to fill).
  MaxHeight    Integer   R/W   Maximum height cap (0 = no limit, stretch to fill).
  Weight       Integer   R/W   Layout weight. 0 = fixed size, >0 = share extra space proportionally.
  Visible      Boolean   R/W   Whether the control is visible.
  Enabled      Boolean   R/W   Whether the control accepts user input.
  BackColor    Long      R/W   Background color as a 32-bit ARGB value.
  ForeColor    Long      R/W   Foreground (text) color as a 32-bit ARGB value.
  TabIndex     Integer   R     Accepted for VB compatibility but ignored. DVX has no tab order.

Common Events

These events are wired on every control loaded from a .frm file. Controls created dynamically at runtime via code only receive Click, DblClick, Change, GotFocus, and LostFocus; the keyboard, mouse, and scroll events below require the control to be defined in the .frm file.

Event Parameters Description
--------- ------------------------------------------- -------------------------------------------
Click (none) Fires when the control is clicked.
DblClick (none) Fires when the control is double-clicked.
Change (none) Fires when the control's value or text changes.
GotFocus (none) Fires when the control receives keyboard focus.
LostFocus (none) Fires when the control loses keyboard focus.
KeyPress KeyAscii As Integer Fires when a printable key is pressed. KeyAscii is the ASCII code.
KeyDown KeyCode As Integer, Shift As Integer Fires when any key is pressed down. KeyCode is the scan code; Shift indicates modifier keys.
KeyUp KeyCode As Integer, Shift As Integer Fires when a key is released.
MouseDown Button As Integer, X As Integer, Y As Integer Fires when a mouse button is pressed over the control.
MouseUp Button As Integer, X As Integer, Y As Integer Fires when a mouse button is released over the control.
MouseMove Button As Integer, X As Integer, Y As Integer Fires when the mouse moves over the control.
Scroll Delta As Integer Fires when the control is scrolled (mouse wheel or scrollbar).

Common Methods

  Method     Parameters   Description
  --------   ----------   -------------------------------------------
  SetFocus   (none)       Gives keyboard focus to this control.
  Refresh    (none)       Forces the control to repaint.

Form

Data Binding

FRM File Format

Form

VB Equivalent: Form -- DVX Widget: Window + VBox/HBox root

The Form is the top-level container representing a DVX window. It is declared in the .frm file with Begin Form FormName. All controls are children of the form's content box, which uses either VBox (default) or HBox layout.

Form Properties

  Property    Type      Default          Description
  ----------  -------   --------------   -------------------------------------------
  Name        String    "Form1"          The form's name, used for event dispatch and Load statement.
  Caption     String    (same as Name)   Window title bar text.
  Width       Integer   400              Window width in pixels. Setting this disables AutoSize.
  Height      Integer   300              Window height in pixels. Setting this disables AutoSize.
  Left        Integer   0                Initial X position. Used when Centered is False.
  Top         Integer   0                Initial Y position. Used when Centered is False.
  Layout      String    "VBox"           Content box layout: "VBox" (vertical) or "HBox" (horizontal).
  AutoSize    Boolean   True             When True, the window shrink-wraps to fit its content.
  Resizable   Boolean   True             Whether the user can resize the window at runtime.
  Centered    Boolean   True             When True, the window is centered on screen. When False, Left/Top are used.

Form Events

  Event         Parameters              Description
  -----------   ---------------------   -------------------------------------------
  Load          (none)                  Fires after the form and all controls are created. This is the default event.
  Unload        (none)                  Fires when the form is being closed or unloaded.
  QueryUnload   Cancel As Integer       Fires before Unload. Set Cancel = 1 to abort the close.
  Resize        (none)                  Fires when the window is resized by the user.
  Activate      (none)                  Fires when the window gains focus.
  Deactivate    (none)                  Fires when the window loses focus.

Form Methods

  Statement           Description
  ------------------  -------------------------------------------
  Load FormName       Load the form (creates the window and controls, fires Load event).
  Unload FormName     Unload the form (fires Unload, destroys window).
  FormName.Show       Make the form visible.
  FormName.Show 1     Show as modal dialog (blocks until closed).
  FormName.Hide       Hide the form without unloading it.

Example

Sub Form_Load ()
    Form1.Caption = "Hello World"
    Print "Form loaded!"
End Sub

Sub Form_QueryUnload (Cancel As Integer)
    If MsgBox("Really quit?", 4) <> 6 Then
        Cancel = 1
    End If
End Sub

Sub Form_Resize ()
    Print "Window resized"
End Sub

Common Properties, Events, and Methods