CDialog Class

Introducing CDialog: A Streamlined Dialog Engine for FreeBasic

CDialog is a lightweight yet powerful dialog engine tailored for FreeBasic developers seeking a clean, high-level approach to building Windows dialogs — without sacrificing control or clarity. Inspired by the straightforwardness of PowerBasic’s DDT model, yet engineered with modern design in mind, CDialog offers structured, maintainable UI development rooted in the familiar logic of the Windows API.

At its core, CDialog replicates and refines the DDT engine, delivering cleaner syntax, robust internal architecture, and simplified message handling. Whether you’re building modal or modeless dialogs, adding controls, or managing layout behavior, CDialog keeps things intuitive and transparent — no bloat, no black boxes.

Among its standout features is the automatic anchoring system, which minimizes the tedium of UI resizing logic. By applying simple declarative rules, it handles control repositioning and scaling automatically — sparing developers the hassle of manual calculations. Crucially, this system works identically for dialogs defined in pixels or dialog units, providing consistency and flexibility across design styles.

And for those who prefer procedural syntax, DDT.inc bridges the gap by exposing DDT-style wrappers atop the CDialog class — allowing developers to adopt CDialog incrementally or stick with the idioms they already know.

Whether you’re modernizing legacy utilities, crafting new tools, or just writing code for fun, CDialog delivers a flexible, DPI-aware foundation that respects both your time and your muscle memory.

Include file: AfxNova/CDialog.inc.

Dialog methods

Control methods

Fonts

Images

Metric conversions

DPI scaling

Layout manager

Colors

Keyboard accelerators

Scrollable dialogs

Helper function

Constructor

Creates instances of the CDialog class.

CONSTRUCTOR (BYREF fontName AS WSTRING = "Segoe UI", BYVAL ptSize AS LONG = 9, _
   BYVAL fontStyle AS BYTE = 0, BYVAL charset AS BYTE = DEFAULT_CHARSET) 

Usage examples

DIM pDialog AS CDialog
DIM pDialog AS CDialog = CDialog("Segoe UI", 9)
DIM pDialog AS CDialog = CDialog("Times New Roman", 10, 2, DEFAULT_CHARSET)

hDialog

Returns the dialog handle.

PROPERTY hDialog () AS HWND

Usage example

DIM hDlg AS HWND = pDlg.hDialog

IsModal

Returns TRUE if the dialog is modal; FALSE otherwise.

FUNCTION IsModal () AS BOOLEAN

Usage example

DIM bModal AS BOOLEAN = pDlg.IsModal

IsCustom

Returns TRUE if it is a custom dialog; FALSE otherwise.

FUNCTION IsCustom () AS BOOLEAN

Usage example

DIM bCustom AS BOOLEAN = pDlg.IsCustom

UsesPixels

Returns TRUE if the dialog uses pixels; FALSE otherwise.

FUNCTION UsesPixels () AS BOOLEAN

Usage example

DIM bUsesPixels AS BOOLEAN = pDlg.UsesPixels

UsesUnits

Returns TRUE if the dialog uses dialog units; FALSE otherwise.

FUNCTION UsesUnits () AS BOOLEAN

Usage example

DIM bUsesUnits AS BOOLEAN = pDlg.UsesUnits

DialogNew

Creates a dialog in memory. A new empty dialog is created, but not yet displayed. Once the dialog has been created and all of the desired controls have been added with, the dialog can be displayed with the DialogShowModeless or DialogSHowModal functions.

If a modeless dialog is created, the application must create a DialogDoEvents message pump for the duration of the dialog. Failure to provide a message pump can result in disruptions to the display of the dialog, or the inability of the dialog to respond to messages such as button clicks, etc. Modal dialogs do not require a message pump.

To change the displayed state of a dialog (i.e., hidden, minimized, etc) after the dialog has been created, use the DialogShowState function.

If a dialog does not have either WS_CHILD or WS_POPUP styles, Windows may enforce a minimum dialog width of some 60-70 dialog units.

You can give to the dialog a class Name of your choice; otherwise, the predefined class #32770” is used.

The overloaded function DialogNewPixels uses pixels instead of dialog units.

FUNCTION DialogNew (BYVAL hParent AS HWND = HWND_DESKTOP, BYREF wszTitle AS WSTRING, _
   BYVAL x AS LONG = -1, BYVAL y AS LONG = -1, BYVAL cx AS LONG = 0, BYVAL cy AS LONG = 0, _
   BYVAL dwStyle AS LONG = 0, BYVAL dwExStyle AS LONG = 0) AS HWND

FUNCTION DialogNew (BYREF wszClassName AS WSTRING, BYVAL hParent AS HWND = HWND_DESKTOP, _
   BYREF wszTitle AS WSTRING = "", BYVAL x AS LONG = -1, BYVAL y AS LONG = -1, _
   BYVAL cx AS LONG = 0, BYVAL cy AS LONG = 0, BYVAL dwStyle AS LONG = 0, _
   BYVAL dwExStyle AS LONG = 0) AS HWND

FUNCTION DialogNewPixels (BYVAL hParent AS HWND = HWND_DESKTOP, BYREF wszTitle AS WSTRING, _
   BYVAL x AS LONG = -1, BYVAL y AS LONG = -1, BYVAL cx AS LONG = 0, BYVAL cy AS LONG = 0, _
   BYVAL dwStyle AS LONG = 0, BYVAL dwExStyle AS LONG = 0) AS HWND

FUNCTION DialogNewPixels (BYREF wszClassName AS WSTRING, BYVAL hParent AS HWND = HWND_DESKTOP, _
   BYREF wszTitle AS WSTRING = "", BYVAL x AS LONG = -1, BYVAL y AS LONG = -1, _
   BYVAL cx AS LONG = 0, BYVAL cy AS LONG = 0, BYVAL dwStyle AS LONG = 0, _
   BYVAL dwExStyle AS LONG = 0) AS HWND

If the style does not include WS_CAPTION, the width and height specify the overall dialog size, including the caption and border, if any. Note that WS_CAPTION is a combination of the WS_BORDER and WS_DLGFRAME styles. The default dialog style includes WS_BORDER and WS_DLGFRAME styles, so it implicitly includes the WS_CAPTION style. | | dwStyle | | | dwExStyle | |

Return value

The Windows window handle assigned by Windows. This handle should be used with subsequent Dialog and Control functions, and may be directly used with Windows API calls.

If the dialog could not be created (i.e., due to low Windows resources), NULL is returned.