TaskDialogCallbackProc callback function

Applies to: desktop apps only

The TaskDialogCallbackProc function is an application-defined function used with the TaskDialogIndirect function. It receives messages from the task dialog when various events occur.

The PFTASKDIALOGCALLBACK type defines a pointer to this callback function. TaskDialogCallbackProc is a placeholder for the application defined function name.

Syntax

HRESULT CALLBACK TaskDialogCallbackProc(
  __in  HWND hwnd,
  __in  UINT uNotification,
  __in  WPARAM wParam,
  __in  LPARAM lParam,
  __in  LONG_PTR dwRefData
);

Parameters

hwnd [in]

Type: HWND

Handle to the TaskDialog window. Do not continue sending messages to hwnd after the callback procedure returns from having been called with TDN_DESTROYED.

uNotification [in]

Type: UINT

One of the following notifications.

Notification	Usage
TDN_BUTTON_CLICKED	Indicates that a button has been selected. The command ID of the button is specified by wParam.
TDN_CREATED	Indicates that the Task Dialog has been created.
TDN_DESTROYED	Indicates that the Task Dialog has been destroyed.
TDN_DIALOG_CONSTRUCTED	Indicates that the Task Dialog has been created but has not been displayed yet.
TDN_EXPANDO_BUTTON_CLICKED	Indicates that the exando button has been selected.
TDN_HELP	Indicates that the F1 key has been pressed while the Task Dialog has focus.
TDN_HYPERLINK_CLICKED	Indicates that a hyperlink has been selected. A pointer to the link text is specified by lParam.
TDN_NAVIGATED	Indicates that navigation has occurred.
TDN_RADIO_BUTTON_CLICKED	Indicates that a radio button has been selected. The command ID of the radio button is specified by wParam.
TDN_TIMER	Indicates that the Task Dialog timer has fired. The total elapsed time is specified by wParam. You can update the progress bar by sending a TDM_SET_PROGRESS_BAR_POS message to the window specified by the hwnd parameter.
TDN_VERIFICATION_CLICKED	Indicates that the Task Dialog verification check box has been selected.

 

wParam [in]

Type: WPARAM

Specifies additional notification information. The contents of this parameter depend on the value of the uNotification parameter.

lParam [in]

Type: LPARAM

Specifies additional notification information. The contents of this parameter depend on the value of the uNotification parameter.

dwRefData [in]

Type: LONG_PTR

Pointer to application specific data. This is the data pointed to by the lpCallbackData member of structure TASKDIALOGCONFIG used to create the task dialog.

Return value

Type: HRESULT

The return value is specific to the notification being processed. When responding to a button click, your implementation should return S_FALSE if the Task Dialog is not to close. Otherwise return S_OK.

Remarks

An application must register this callback function by passing its address in the pfCallback member of the TASKDIALOGCONFIG structure that is passed via pointer through TaskDialogIndirect.

Requirements

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Build date: 3/6/2012