ThinBASIC Modules > UI (User Interface) > CONTROLS > Control Types > Button Control > Button Control Creation

Description

Add a command button to a dialog.

A command button is a button that causes an action to occur when the button is clicked. A common example of a command button is the "OK" button on a message box dialog.

Syntax

hndl = CONTROL ADD BUTTON [Name ControlName],, hwnd, ctrlID, txt, xPos, yPos, Width, Height [, [Style] [, [ExStyle]]] [[,] CALL CallBack]

Returns

Number

Control window handler.

Parameters

Name	Type	Optional	Meaning
ControlName	String	Yes	Optional name for the control. This name must be globally unique, and is used to create a global variable to be used with control name methods and properties.
hwnd	Number	No	Handle of the dialog containing the control
ctrlID	Number	No	Control identifier
txt	String	No	A text expression representing the text you want to assign to the control.
xPos	Number	No	Horizontal position of the control inside the dialog
yPos	Number	No	Vertical position of the control inside the dialog
Width	Number	No	Control width
Height	Number	No	Control height
Style	Number	Yes	Primary style of the control. See BUTTON Style equates If no Style is specified, the following expression is assumed as default: %BS_CENTER OR %BS_VCENTER OR %WS_TABSTOP
ExStyle	Number	Yes	Extended style of the control. See BUTTON ExStyle equates If no ExStyle is specified, the following expression is assumed as default: %WS_EX_LEFT
CallBack	Function	Yes	Optional name of a Callback Function that receives all %WM_COMMAND and %WM_NOTIFY messages for the control. If a callback for the control is not designated, you must create a dialog Callback Function to process messages from your control. If the Callback Function processes a message, it should return %TRUE (non-zero) to prevent the message being passed unnecessarily to the dialog callback (if one exists). The dialog callback should also return %TRUE if the notification message is processed by that Callback Function.

Remarks

In general, if the control Callback Function processes a message, it should return %TRUE (non-zero) to prevent the message being passed unnecessarily to the dialog callback (if one exists). The dialog callback should also return %TRUE, if the notification message is processed by that Callback Function.

Notification messages are sent to the Callback Function, with CBMSG = %WM_COMMAND, CBCTL holding the ID (ctrlID) of the control, and CBCTLMSG holding the following values:

%BN_CLICKED Sent when the user clicks a mouse button, or activates the button with the hot-key (unless the button has been disabled).

%BN_DISABLE Sent when a button is disabled.

%BN_KILLFOCUS Sent when a button loses the keyboard focus. The button must include the %BS_NOTIFY style.

%BN_SETFOCUS Sent when a button receives the keyboard focus. The button must include the %BS_NOTIFY style.

When a Callback Function receives a %WM_COMMAND message, it should explicitly test the value of CBCTL and CBCTLMSG to guarantee it is responding appropriately to the notification message.

Restrictions