Dynamic Dialog Tools

(The contents of this page are (C) PowerBasic Inc.)

More often that not, your application will need to communicate with the person or persons using it. Either getting a set of input values for some calculation, or returning the result of that calculation (perhaps even both). In a Windows GUI application that usually means spending time in a forms designer such as Visual Basic or the Microsoft Dialog Editor. In a complex application with hundreds or even thousands of input fields that makes sense. But when you simply need to get smaller amounts of information, or more importantly, when the input dialog needs to be generated dynamically at run time, there is no easy solution. Until now.

PowerBASIC's Dynamic Dialog Tools allow you to use traditional programming methods that have been used by BASIC programmers for years. To create a dialog, you don't need a fancy forms designer, just a few statements of source code. In just a few short, simple steps you can create a dialog window, add text-boxes and buttons, and create a fully functional GUI application.

Overview of DDT-related functions:

Callback Function

Cbctl Function
Cbctlmsg Function
Cbhndl Function
Cblparam Function
Cbmsg Function
Cbwparam Function
Combobox Add
Combobox Get Text
Combobox Delete
Combobox Reset

Combobox Select

Control Disable

Control Get Check

Control Get Loc

Control Get Size

Control Get Text

Control Set Check

Control Set Focus

Control Set Image

Control Set Loc

Control Set Size

Callback Function
Defines a special, simplified form of user function which is used exclusively for your callback procedures. Callback Functions are automatically executed in response to certain events which occur in your program. When a Callback Function is listed in a DIALOG SHOW statement, it is executed whenever any message related to any part of the dialog is received by PowerBASIC. When a Callback function is listed in a CONTROL ADD statement, it is executed whenever a wm_command message for that specific control is received by PowerBASIC.
Callback Functions are only executed by PowerBASIC internals or Windows. You should never execute a Callback Function from your application code.

Cbctl Function
Returns the LoWrd of wParam. It is only valid within a callback function.

Cbctlmsg Function
Returns the HiWrd of wParam in a dialog callback function. It is only valid within a callback function.

Cbhndl Function
Returns the hWnd param in a callback function. It is only valid within a callback function.

Cblparam Function
Returns the lParam parameter in a callback function. It is only valid within a callback function.

Cbmsg Function
Returns the wMsg parameter in a callback function. It is only valid within a callback function.

Cbwparam Function
Returns the wParam parameter in a callback function. It is only valid within a callback function.

Combobox Add
Add a string to a combobox.

Combobox Get Text
Get the text of the currently selected item in a specified combobox.

Combobox Delete
Delete a string at the specified position within a combobox.

Combobox Reset
Remove all of the contents of the specified comboboxbox.

Combobox Select
Copy the specified listbox item at into the editbox portion of a combobox.

Control Add
Adds a control to the specified Dialog Box.
The Following controls are build-in, but custom controls can also be used.

A regular button, with text.

Check3state

A 3-state checkbox. (On / Off / Inactive).

A regular checkbox (On / Off).

A frame-control, also known as group-control.

Display an enclosed icon or bitmap picture.

Same as image, but image will be stretched to fit dimensions.

A button with an icon or Bitmap on it.

Button with icon or bitmap, stretched to fit.

Displays a line of text.

Radiobutton (allowing Only one choice to be selected).

Scrollbar (Duh.)

An edit-box, to allow user input.

-	A combobox.

Control Disable
Disables mouse and keyboard input from reaching the specified control. Most standard controls are automatically "grayed" to give the user a visual indication that it is not available for interaction.

Control Enable
Enables mouse and keyboard input to the specified control. This is the default condition upon initial "show" of a dialog.

Control Get Check
The "check state" of an option button, checkbox, or check3state is assigned to a long integer variable.
0=unchecked, 1=checked, 2=grayed (only if a 3state).

Control Get Loc
Retrieves the location of the specified control (in dialog units, relative to the client area of the dialog), and assigns it to the long integer variables.

Control Get Size
Retrieves the size of the specified control (in dialog units), and assigns it to the long integer variables.

Control Get Text
The text of the specified control (or dialog/window title) is copied to a string variable.

Control Handle
Retrieves the windows handle of a control, given the handle of the parent dialog and the id used to create it, and assigns it to a long integer variable. If the requested control cannot be found, a value of zero is returned. This control handle may be needed to successfully execute certain PowerBASIC statements, as well as some Windows API functions.

Control Kill
Destroys the specified control.

Control Send
Sends a windows message to the specified control, which is identified by the parent dialog handle and control id combination. It optionally assigns the result to a long integer variable.

Control Set Check
Set the "check state" of an option button, checkbox, or check3state.
0=unchecked, 1=checked, 2=grayed (only if a 3state).

Control Set Focus
The specified control receives the focus -- keyboard input is directed to it.

Control Set Image
A new bitmap or icon image is displayed on the specified control. However, bitmaps and icons cannot be interchanged. A bitmap can only be changed to another bitmap, likewise with icons.

Control Set Loc
Moves the specified control to a new location. (In dialog units, relative to the client area of the dialog)

Control Set Size
Changes the size of the specified control (in dialog units).

Control Set Text
The text of the control (or dialog/window title) is changed to the specified string expression.

Declare Callback Function
Declares a special Callback Function prior to its full definition. It must be declared as returning a long integer value, or if ambiguous, it defaults to long integer. It must include no parameters.

Dialog Disable
Disables mouse and keyboard input from reaching any control in the specified dialog. Controls within the dialog are not automatically "grayed", so it is necessary to use CONTROL DISABLE with each, if you wish to provide a visual indication they are not available for interaction.

Dialog Doevents
Processes a pending window or dialog message and releases the remainder of the timeslice to Windows if there are no active dialogs.

Dialog Enable
Enables mouse and keyboard input to the specified control. This is the default condition upon initial "show" of a dialog.

Dialog End
The specified Dialog is destroyed.

Dialog Get Client
Retrieves the size of the client area of the specified dialog (in dialog units), and assigns it to the long integer variables.

Dialog Get Loc
Retrieves the location of the specified dialog (in dialog units, relative to the client area of the parent dialog or if none, the screen), and assigns it to long integer variables.

Dialog Get Size
Retrieves the total size of the specified dialog (in dialog units), and assigns it to long integer variables.

Dialog New
A new dialog is defined, but not yet displayed. The dialog can be set to appear on specified coordinates, or centered on the screen.

Dialog Pixels
Converts pixels to dialog units, based upon the appropriate ratios for the specified dialog.

Dialog Send
Sends a windows message to the specified control/window/dialog, and optionally assigns the result to a long integer variable.

Dialog Set Loc
Moves the specified dialog to the location (in dialog units, relative to the client area of the parent dialog or if none, the screen).

Dialog Set Size
Changes the size of the specified dialog (in dialog units).

Dialog Show Modal
The specified modal dialog is made visible. The Callback function is executed each time any message for this dialog occurs.
A modal dialog halts the application until it is closed again through a callback function.

Dialog Show Modeless
The specified modal dialog is made visible. The Callback function is executed each time any message for this dialog occurs.
A modeless dialog will not halt the application when called.

Dialog Show State
Used to change the state/appearance of the specified dialog. This can be used to programmatically minimize, maximize, etc. a dialog.

Dialog Units
Converts dialog units to pixels, based upon the appropriate ratios for the specified dialog.

Listbox Add
Adds a string to the specified listbox.

Listbox Get Text
Get the text of the currently selected item in the specified listbox.

Listbox Delete
Delete the string at the specified position in a listbox.

Listbox Reset
Remove all contents of the specified listbox.

Listbox Select
Select the string at the specified position in a listbox.

Menu Add Popup
A previously defined popup menu is added to the specified menu.

Menu Add String
A new menu string is added to a menu.

Menu Attach
A previously defined menu is attached to a dialog window.

Menu Delete
Deletes an item from the specified menu.

Menu Draw Bar
Causes the main menu bar in the Dialog specified to be redrawn. This statement must be executed any time the menu bar changes after the dialog has been created/displayed with DIALOG SHOW.

Menu Get State
The state of the menu item specified is copied to a long integer variable.

Menu Get Text
The text of the specified menu item is copied to a string variable.

Menu Set State
Changes the state of a menu item:
Enabled, Disabled, Checked, Un-checked, Hilighted, Un-hilighted, Grayed.

Menu Set Text
The menu item specified is changed to the new string expression.

MousePtr
Changes the mouse pointer to a new shape:
Default, Arrow, Cross, Ibeam, Arrow, SizeAll, SizeNESW, SizeNS, SizeNWSE, SizeWE, UpArrow, Wait, No, AppStarting.

The text on this page is (C) PowerBasic Inc.
HTML-conversion by Marc van den Dikkenberg

Last update: 27 May 1999