TaskDialog function

The TaskDialog function creates, displays, and operates a task dialog. The task dialog contains application-defined message text and title, icons, and any combination of predefined push buttons. This function does not support the registration of a callback function to receive notifications.

Syntax

HRESULT TaskDialog(
  HWND                           hwndOwner,
  HINSTANCE                      hInstance,
  PCWSTR                         pszWindowTitle,
  PCWSTR                         pszMainInstruction,
  PCWSTR                         pszContent,
  TASKDIALOG_COMMON_BUTTON_FLAGS dwCommonButtons,
  PCWSTR                         pszIcon,
  int                            *pnButton
);

Parameters

hwndOwner

Type: HWND

Handle to the owner window of the task dialog to be created. If this parameter is NULL, the task dialog has no owner window.

hInstance

Type: HINSTANCE

Handle to the module that contains the icon resource identified by the pszIcon member, and the string resources identified by the pszWindowTitle and pszMainInstruction members. If this parameter is NULL, pszIcon must be NULL or a pointer to a null-terminated, Unicode string that contains a system resource identifier, for example, TD_ERROR_ICON.

pszWindowTitle

Type: PCWSTR

Pointer to the string to be used for the task dialog title. This parameter is a null-terminated, Unicode string that contains either text, or an integer resource identifier passed through the MAKEINTRESOURCE macro. If this parameter is NULL, the filename of the executable program is used.

pszMainInstruction

Type: PCWSTR

Pointer to the string to be used for the main instruction. This parameter is a null-terminated, Unicode string that contains either text, or an integer resource identifier passed through the MAKEINTRESOURCE macro. This parameter can be NULL if no main instruction is wanted.

pszContent

Type: PCWSTR

Pointer to a string used for additional text that appears below the main instruction, in a smaller font. This parameter is a null-terminated, Unicode string that contains either text, or an integer resource identifier passed through the MAKEINTRESOURCE macro. Can be NULL if no additional text is wanted.

dwCommonButtons

Type: TASKDIALOG_COMMON_BUTTON_FLAGS

Specifies the push buttons displayed in the dialog box. This parameter may be a combination of flags from the following group.

Note  If no buttons are specified, the dialog box will contain the OK button by default.
 
Value Meaning
TDCBF_OK_BUTTON
The task dialog contains the push button: OK.
TDCBF_YES_BUTTON
The task dialog contains the push button: Yes.
TDCBF_NO_BUTTON
The task dialog contains the push button: No.
TDCBF_CANCEL_BUTTON
The task dialog contains the push button: Cancel. This button must be specified for the dialog box to respond to typical cancel actions (Alt-F4 and Escape).
TDCBF_RETRY_BUTTON
The task dialog contains the push button: Retry.
TDCBF_CLOSE_BUTTON
The task dialog contains the push button: Close.

pszIcon

Type: PCWSTR

Pointer to a string that identifies the icon to display in the task dialog. This parameter must be an integer resource identifier passed to the MAKEINTRESOURCE macro or one of the following predefined values. If this parameter is NULL, no icon will be displayed. If the hInstance parameter is NULL and one of the predefined values is not used, the TaskDialog function fails.

Value Meaning
TD_ERROR_ICON
A stop-sign icon appears in the task dialog.
TD_INFORMATION_ICON
An icon consisting of a lowercase letter i in a circle appears in the task dialog.
TD_SHIELD_ICON
A security shield icon appears in the task dialog.
TD_WARNING_ICON
An exclamation-point icon appears in the task dialog.

pnButton

Type: int*

When this function returns, contains a pointer to an integer location that receives one of the following values:

Value Description
0 Function call failed. Refer to return value for more information.
IDCANCEL Cancel button was selected, Alt-F4 was pressed, Escape was pressed or the user clicked on the close window button.
IDNO No button was selected.
IDOK OK button was selected.
IDRETRY Retry button was selected.
IDYES Yes button was selected.
 

If this value is NULL, no value is returned.

Return Value

Type: HRESULT

This function can return one of these values.

Return code Description
S_OK
The operation completed successfully.
E_OUTOFMEMORY
There is insufficient memory to complete the operation.
E_INVALIDARG
One or more arguments are not valid.
E_FAIL
The operation failed.

Remarks

When you use a task dialog box to indicate that the system is low on memory, the strings pointed to by the pszMainInstruction and pszWindowTitle parameters should not be taken from a resource file since an attempt to load the resource may fail.

If you create a task dialog while a dialog box is present, use a handle to the dialog box as the hWndParent parameter. The hWndParent parameter should not identify a child window, such as a control in a dialog box.

Because task dialog boxes use the correct system-defined UI elements, you should use them instead of using message boxes created with the MessageBox function. To achieve more functionality, use TaskDialogIndirect.

The following example code, to be included as part of a larger program, shows how to create a task dialog and capture input.

int nButtonPressed = 0;
TaskDialog(NULL, hInst, 
    MAKEINTRESOURCE(IDS_APPLICATION_TITLE),
    MAKEINTRESOURCE(IDS_DOSOMETHING), 
    MAKEINTRESOURCE(IDS_SOMECONTENT), 
    TDCBF_OK_BUTTON | TDCBF_CANCEL_BUTTON,
    TD_WARNING_ICON, 
    &nButtonPressed);

if (IDOK == nButtonPressed) { // OK button pressed } else if (IDCANCEL == nButtonPressed) { // Cancel pressed }

Requirements

   
Windows version Windows Vista [desktop apps only] Windows Server 2008 [desktop apps only]
Target Platform Windows
Header commctrl.h (include Commctrl.h)
Library Comctl32.lib
DLL Comctl32.dll (version 6)

See Also

Dialog Boxes