DVX BASIC Control Reference

This document describes every VB-style control available in DVX BASIC. Each control maps to an underlying DVX widget loaded dynamically via .wgt DXE files. Properties and methods are dispatched through interface descriptors registered by each widget.

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

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.

Common Methods

Form

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

Form Events

Form Methods (called on the form object)

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

CommandButton

A push button that triggers an action when clicked. Created with wgtButton(parent, text).

Type-Specific Properties

No additional type-specific properties beyond common properties and Caption.

Default Event: Click

Example

Begin Form Form1
    Caption = "Button Demo"
    Begin CommandButton Command1
        Caption = "&Click Me!"
    End
End

Sub Command1_Click ()
    MsgBox "Button was clicked!"
End Sub

Label

A static text label. Supports left, center, and right alignment.

Type-Specific Properties

Default Event: Click

Example

Begin Label Label1
    Caption   = "Hello, World!"
    Alignment = "Center"
End

TextBox

A single-line text input field. Supports data binding via DataSource and DataField properties.

Type-Specific Properties

Default Event: Change

Example

Begin TextBox Text1
    Text = "Enter text here"
End

Sub Text1_Change ()
    Label1.Caption = "You typed: " & Text1.Text
End Sub

TextArea

A multi-line text editing area. This is a DVX extension with no direct VB3 equivalent (VB uses a TextBox with MultiLine=True). Supports syntax colorization, line numbers, auto-indent, and find/replace via the C API.

Type-Specific Properties

Default Event: Change

CheckBox

A toggle control with a label. Checked state is exposed as a Boolean.

Type-Specific Properties

Default Event: Click

Example

Begin CheckBox Check1
    Caption = "Enable feature"
End

Sub Check1_Click ()
    If Check1.Value Then
        Label1.Caption = "Feature ON"
    Else
        Label1.Caption = "Feature OFF"
    End If
End Sub

OptionButton

A radio button for mutually exclusive choices. DVX uses a radio group container; individual OptionButtons are children of the group. The Value property returns the button's index within its group.

Type-Specific Properties

Type-Specific Methods

Default Event: Click

Frame

A container with a titled border. Child controls are placed inside the frame using VBox layout. In the .frm file, nest Begin/End blocks inside the Frame block.

Type-Specific Properties

Container: Yes

Default Event: Click

Example

Begin Frame Frame1
    Caption = "Options"
    Begin CheckBox Check1
        Caption = "Option A"
    End
    Begin CheckBox Check2
        Caption = "Option B"
    End
End

VBox

A container that arranges its children vertically, top to bottom. No title or border. Use Weight on children to distribute extra space.

Container: Yes

Default Event: Click

No type-specific properties.

HBox

A container that arranges its children horizontally, left to right. Use Weight on children to distribute extra space.

Container: Yes

Default Event: Click

No type-specific properties.

ListBox

A scrollable list of selectable items. Items are managed via methods (AddItem, RemoveItem, Clear). Supports single and multi-select modes.

Type-Specific Properties

Type-Specific Methods

Default Event: Click

Example

Sub Form_Load ()
    List1.AddItem "Apple"
    List1.AddItem "Banana"
    List1.AddItem "Cherry"
End Sub

Sub List1_Click ()
    Dim idx As Integer
    idx = List1.ListIndex
    If idx >= 0 Then
        Label1.Caption = "Selected: " & List1.List(idx)
    End If
End Sub

ComboBox

A combination of a text input and a drop-down list. The user can type text or select from the list. Supports the same AddItem/RemoveItem/Clear/List methods as ListBox.

Type-Specific Properties

Type-Specific Methods

Same as ListBox: AddItem, RemoveItem, Clear, List.

Default Event: Click

DropDown

A read-only drop-down list. Unlike ComboBox, the user cannot type free text; they can only select from the provided items. Supports AddItem/RemoveItem/Clear/List.

Type-Specific Properties

Type-Specific Methods

Same as ListBox: AddItem, RemoveItem, Clear, List.

Default Event: Click

HScrollBar

A horizontal slider/scrollbar control. The value ranges between a minimum and maximum set at creation time (default 0 to 100).

Type-Specific Properties

Default Event: Change

Example

Begin HScrollBar HScroll1
    MinWidth = 200
End

Sub HScroll1_Change ()
    Label1.Caption = "Value: " & Str$(HScroll1.Value)
End Sub

SpinButton

A numeric input with up/down buttons. Supports integer mode (default) and real-number mode with configurable decimal places.

Type-Specific Properties

Type-Specific Methods

Default Event: Change

Timer

A non-visual control that fires its event at a regular interval. The Timer widget is invisible at runtime -- it has no on-screen representation.

Type-Specific Properties

Type-Specific Methods

Type-Specific Events

Example

Begin Timer Timer1
    Interval = 1000
    Enabled  = True
End

Dim counter As Integer

Sub Timer1_Timer ()
    counter = counter + 1
    Label1.Caption = "Ticks: " & Str$(counter)
End Sub

PictureBox

A drawing surface (canvas). Supports drawing lines, rectangles, circles, text, and individual pixels. Can save and load BMP images. The default canvas size is 64x64 pixels.

Type-Specific Methods

Additional drawing methods (DrawLine, DrawRect, FillRect, FillCircle, SetPixel, GetPixel, DrawText, Save, Load) are available through the C API but not currently exposed through BASIC interface descriptors.

Default Event: Click

Image

A static image display control. Loads BMP images from file. Cannot be placed via the designer toolbox (requires pixel data at creation time); typically created in code or loaded via the Picture property.

Type-Specific Properties

Default Event: Click

ImageButton

A button that displays an image instead of text. Like Image, it requires pixel data at creation time and is typically loaded via the Picture property.

Type-Specific Properties

Default Event: Click

ProgressBar

A horizontal progress indicator bar.

Type-Specific Properties

No type-specific events or methods. No default event.

ListView

A multi-column list with column headers. Supports sorting, multi-select, and drag-to-reorder. Columns are configured via the C API (SetColumns, SetData).

Type-Specific Properties

Type-Specific Methods

Default Event: Click

TreeView

A hierarchical tree of expandable/collapsible nodes. Nodes are created via the C API (wgtTreeItem). Supports multi-select and drag-to-reorder.

Type-Specific Methods

Default Event: Click

TabStrip

A tabbed container. Each tab page is a separate container that holds child controls. Switching tabs shows one page and hides others.

Type-Specific Properties

Type-Specific Methods

Container: Yes

Default Event: Click

Splitter

A resizable split pane. Holds exactly two child widgets separated by a draggable divider. Default orientation is vertical (top/bottom split).

Type-Specific Properties

Container: Yes

No default event.

ScrollPane

A scrollable container. Place child controls inside and the ScrollPane automatically provides scrollbars when the content exceeds the visible area.

Type-Specific Properties

Container: Yes

No default event.

WrapBox

A container that arranges children in a flowing layout, wrapping to the next row when the available width is exceeded. Similar to CSS flexbox with flex-wrap: wrap.

Type-Specific Properties

Container: Yes

Default Event: Click

Line

A visual separator line. The underlying widget supports both horizontal and vertical orientations. The default (via BASIC) is horizontal.

No type-specific properties, events, or methods.

Spacer

An invisible layout spacer. Takes up space in the layout without rendering anything. Useful for pushing controls apart. Give it a Weight to absorb extra space.

No type-specific properties, events, or methods.

Toolbar

A horizontal container styled as a toolbar, with compact padding and spacing. Place buttons, labels, or other controls inside.

Container: Yes

No type-specific properties, events, or methods.

StatusBar

A horizontal container styled as a status bar, typically placed at the bottom of a form. At the C API level it accepts child widgets, but it is not registered as a container in the form runtime, so child controls cannot be nested inside it in .frm files. Set its Caption property to display status text.

No type-specific properties, events, or methods.

Terminal

A VT100/ANSI terminal emulator widget. Supports ANSI escape sequences, scrollback buffer, and serial communication. Default size is 80 columns by 25 rows.

Type-Specific Properties

Type-Specific Methods

No default event.

Data

A data access control that connects to a SQLite database and provides record navigation. Other controls can bind to a Data control via their DataSource and DataField properties. See the Data Binding section for details.

Type-Specific Properties

Type-Specific Methods

Type-Specific Events

DBGrid

A data-bound grid that displays records from a Data control in a tabular format. Columns are auto-generated from the query results. Bind it using the DataSource property.

Type-Specific Properties

Type-Specific Methods

Type-Specific Events

Data Binding

DVX BASIC provides VB3-style data binding through three properties that can be set on most controls:

How It Works

1. Place a Data control on the form and set its DatabaseName and RecordSource properties.
2. Place one or more display/edit controls (TextBox, Label, etc.) and set their DataSource to the Data control's name and DataField to a column name.
3. When the form loads, the Data control auto-refreshes: it opens the database, runs the query, and navigates to the first record.
4. Bound controls are updated automatically each time the Data control repositions (the Reposition event fires, and the runtime pushes the current record's field values into all bound controls).
5. When a bound control loses focus (LostFocus), its current text is written back to the Data control's record cache, and Update is called automatically to persist changes.

Master-Detail Binding

For hierarchical data (e.g. orders and order items), use two Data controls:

1. A master Data control bound to the parent table.
2. A detail Data control with its MasterSource set to the master's name, MasterField set to the key column in the master, and DetailField set to the foreign key column in the detail table.

When the master record changes, the detail Data control automatically re-queries using the master's current value for filtering. All controls bound to the detail are refreshed.

DBGrid Binding

Set the DBGrid's DataSource to a Data control name. The grid auto-populates columns from the query results and refreshes whenever the Data control refreshes.

Example

VERSION DVX 1.00
Begin Form frmData
    Caption      = "Data Binding Example"
    AutoSize     = False
    Width        = 400
    Height       = 280
    Begin Data Data1
        DatabaseName = "myapp.db"
        RecordSource = "customers"
    End
    Begin Label lblName
        Caption = "Name:"
    End
    Begin TextBox txtName
        DataSource = "Data1"
        DataField  = "name"
    End
    Begin Label lblEmail
        Caption = "Email:"
    End
    Begin TextBox txtEmail
        DataSource = "Data1"
        DataField  = "email"
    End
End

Sub Data1_Reposition ()
    Print "Current record changed"
End Sub

Sub Data1_Validate (Cancel As Integer)
    If txtName.Text = "" Then
        MsgBox "Name cannot be empty!"
        Cancel = 1
    End If
End Sub

Menu System

Menus are defined in the .frm file using Begin Menu blocks. Each menu item has a name, caption, and nesting level. Menu items fire Click events dispatched as MenuName_Click.

FRM Syntax

Begin Form Form1
    Caption = "Menu Demo"

    Begin Menu mnuFile
        Caption = "&File"
        Begin Menu mnuOpen
            Caption = "&Open"
        End
        Begin Menu mnuSave
            Caption = "&Save"
        End
        Begin Menu mnuSep1
            Caption = "-"
        End
        Begin Menu mnuExit
            Caption = "E&xit"
        End
    End

    Begin Menu mnuEdit
        Caption = "&Edit"
        Begin Menu mnuCopy
            Caption = "&Copy"
        End
        Begin Menu mnuPaste
            Caption = "&Paste"
        End
    End
End

Menu Item Properties

Nesting

Menu items are nested by placing Begin Menu blocks inside other Begin Menu blocks:

• Level 0: top-level menu bar headers (e.g. "File", "Edit").
• Level 1: items within a top-level menu.
• Level 2+: submenu items.

A level-0 menu that contains children becomes a top-level menu header. A non-level-0 menu that contains children becomes a submenu.

Event Dispatch

Each clickable menu item (not headers, not separators) receives a unique numeric ID at load time. When clicked, the form's onMenu handler maps the ID to the menu item's name and fires MenuName_Click.

Sub mnuOpen_Click ()
    MsgBox "Open was clicked"
End Sub

Sub mnuExit_Click ()
    Unload Form1
End Sub

Control Arrays

DVX BASIC supports VB-style control arrays. Multiple controls can share the same name, differentiated by an Index property. When an event fires on a control array element, the element's index is passed as the first parameter.

Defining Control Arrays in FRM

Begin CommandButton Command1
    Caption = "Button A"
    Index   = 0
End
Begin CommandButton Command1
    Caption = "Button B"
    Index   = 1
End
Begin CommandButton Command1
    Caption = "Button C"
    Index   = 2
End

Event Handler Convention

When a control has an Index property (>= 0), the event handler receives Index As Integer as the first parameter, before any event-specific parameters.

Sub Command1_Click (Index As Integer)
    Select Case Index
        Case 0
            MsgBox "Button A clicked"
        Case 1
            MsgBox "Button B clicked"
        Case 2
            MsgBox "Button C clicked"
    End Select
End Sub

Accessing Array Elements in Code

Use the indexed form ControlName(Index) to access a specific element:

Command1(0).Caption = "New Text"
Command1(1).Enabled = False

FRM File Format

The .frm file is a text file that describes a form's layout, controls, menus, and code. It follows a format compatible with VB3 .frm files, with DVX-specific extensions.

Structure

VERSION DVX 1.00
Begin Form FormName
    form-level properties...

    Begin Menu mnuFile
        Caption = "&File"
        Begin Menu mnuOpen
            Caption = "&Open"
        End
    End

    Begin TypeName ControlName
        property = value
        ...
    End

    Begin Frame Frame1
        Caption = "Group"
        Begin TypeName ChildName
            ...
        End
    End
End

BASIC code follows...

Sub FormName_Load ()
    ...
End Sub

Rules

• The VERSION line is optional. VERSION DVX 1.00 marks a native DVX form. VB forms with version <= 2.0 are accepted for import.
• The form block begins with Begin Form Name and ends with End.
• Controls are nested with Begin TypeName Name / End.
• Container controls (Frame, VBox, HBox, Toolbar, TabStrip, ScrollPane, Splitter, WrapBox) can have child controls nested inside them.
• Properties are assigned as Key = Value. String values are optionally quoted.
• Everything after the form's closing End is BASIC source code.
• Comments in the form section use ' (single quote).
• Blank lines are ignored in the form section.

Common FRM Properties

DVX BASIC Control Reference -- Generated from source code analysis of formrt.c, ideProperties.c, ideDesigner.c, and widget DXE interface descriptors.