OKCancelAsynchronous (Function)

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Features of the dialog box
Line break in the dialog box
Miscellaneous
Application in the background: Specific case from Android 10

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OKCancelAsynchronous (Function)

In french: OKAnnulerAsynchrone

Displays a message in a standard non-blocking dialog box with the answers "OK" and "Cancel" and calls a WLanguage procedure with the user's response.

Remarks:

This is a non-blocking dialog box. The WLanguage code that follows the call to OKCancelAsynchronous continues to run. To close the window, the user must validate one of the buttons. When the user clicks one of the buttons, the code of a WLanguage procedure is run.
In the WLanguage code following the call to the function, another modal window cannot be opened before closing the dialog box.
WINDEV allows you to apply the skin template of your project to this dialog box. For more details, see Customizing dialog boxes.

Example

// Choice used to exit the program
OKCancelAsynchronous(No, "Do you want to exit the program?", MyProcedure_OKCancel)

INTERNAL PROCEDURE MyProcedure_OKCancel(nResponse int)
	SWITCH nResponse
		CASE Yes: 
		ToastDisplay("OK button")
		Close()
		CASE No: ToastDisplay("Cancel button")
	END
END

Syntax

Displaying an OK/Cancel dialog box Hide the details

OKCancelAsynchronous([<Selected button>, ] <Text> , <WLanguage procedure>)

<Selected button>: Optional boolean

Button selected by default in the dialog box:
No "Cancel" button selected by default.
True
(by default) "OK" button selected by default.

<Text>: Character string

Text to display.

<WLanguage procedure>: Name of the procedure or lambda procedure

Name of the WLanguage procedure ("callback" procedure) called when the user clicks one of the buttons in the confirmation window.
This procedure is used to find out which button was clicked, and to run a specific process if necessary.
For more details on this procedure, see Parameters of the procedure used by OKCancelAsynchronous.
This WLanguage procedure can correspond to:
a name of a global or local procedure,
a name of an internal procedure,
a lambda procedure.

Remarks

Features of the dialog box

The title of the dialog box corresponds to the title of the current window (or page).
To comply with the system specifications, the title of dialog box is empty by default. To define this title, use NextTitle.
To modify or define the title of dialog box, use NextTitle.

The message is aligned to the left.
The captions of buttons depend on the runtime language of Windows.
The maximum number of characters cannot exceed 4096. If a larger string is passed as parameter, it will be truncated.
The icon displayed (exclamation mark) cannot be modified.

To customize this dialog box (and all the system dialog boxes in your application), check "Customize system windows (Info, YesNo, Confirm, Dialog)" in the "Style" tab of the project description. For more details, see Customizing dialog boxes.

Line break in the dialog box

The CR string (Carriage Return) can be used to force a break to the next line. For example:

OKCancelAsynchronous("Caution: you are going to delete this record" + CR + ...
	"Do you want to continue?", MyProcedure)

You also have the ability to use the syntax of multiline strings. For example:

OKCancelAsynchronous(
[
Caution: you are going to delete this record.

Do you want to continue?
], Procedure_OKCancelAsynchronous)

Miscellaneous

Timers (TimerSys) are not stopped when this function is called.
Windows events are not stopped when this function is called.
DelayBeforeClosing limits how long the message is displayed. The dialog box is automatically closed. For question or confirmation dialog boxes, the default button corresponds to the expected answer.
The text of the buttons is displayed in the system language.
This function must not be used:
- in the "Resize" event of the window. Otherwise, the application will be locked.
- in the "Change the orientation" event of the window.
- in the "Move to the foreground" event associated with the project.
  Remark: However, the function can be used in the "Move to the foreground" event of a window.
- in a thread.

Application in the background: Specific case from Android 10

From Android 10, it is no longer possible to open a window when the application is in the background.

OKCancelAsynchronous can open a window. If this function is used while the application is in the background, a fatal error will occur.

Tips:

It is possible to determine if the application is in the background using InBackgroundMode.
If an application needs to interact with the user while it is in the background, the solution is to display a notification (via the Notification type). The application will be brought back to the foreground when the notification is clicked, if the ActivateApplication property is set to True. You can also open a window from the procedure passed to the ActionClick property.

For more details, see Android 10: Behavior of applications in the background.

Component: wd300obj.dll