• Features of the dialog box
  • Line break in the dialog box
  • Miscellaneous
  • Application in the background: Specific case from Android 10
WindowsLinuxUniversal Windows 10 AppJavaReports and QueriesUser code (UMC)
WindowsLinuxPHPWEBDEV - Browser code
AndroidAndroid Widget iPhone/iPadIOS WidgetApple WatchMac CatalystUniversal Windows 10 App
Stored procedures
Displays a message in a standard dialog box that proposes "Yes" and "No" and returns the user's choice.
Yes / No dialog
  • This is a blocking dialog box. To continue running the application, the user must validate one of the buttons.
    AndroidiPhone/iPad To avoid blocking the application, use YesNoAsynchronous.
Universal Windows 10 AppAndroidiPhone/iPad
// Exit choice
IF YesNo("Do you want to exit the program?") = Yes THEN
Universal Windows 10 AppAndroidiPhone/iPad

Displaying a Yes/No dialog box Hide the details

<Result> = YesNo([<Selected button>, ] <Text> [, <Line 2> [... [, <Line N>]]])
<Result>: Integer constant
Identifies the button selected by the user:
No (or 0)The user selected [NO]
or closed the dialog box via the 'X' icon.
Yes (or 1)The user selected [YES]
<Selected button>: Optional integer constant
Button selected by default in the dialog box:
No (or 0)The "No" button is selected by default.
Yes (or 1)
(Default value)
The "Yes" button is selected by default.
<Text>: Character string
Text to display.
<Line 2>: Optional character string
Text displayed on the second line.
<Line N>: Optional character string
Text displayed on the Nth line.

Features of the dialog box

  • The title of the dialog box corresponds to the title of the current window (or page).
    AndroidiPhone/iPad 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.

Line break in the dialog box

The CR string (Carriage Return) can be used to force a break to the next line. For example:
YesNo("The XXX form was modified." + CR + ...
"Do you want to save it before exiting?")
is equivalent to:
YesNo("The XXX form was modified.", ...
"Do you want to save it before exiting?")
You also have the ability to use the syntax of multiline strings. For example:
The XXX form has been modified.
Do you want to save changes before closing?
Universal Windows 10 AppAndroidiPhone/iPad


  • Timers (TimerSys) are not stopped when this function is called.
  • The text of the buttons is displayed in the system language.
  • iPhone/iPad This function must not be used:
    • in the event "Resizing" of the window. Otherwise, the application will be locked.
    • in the event "Changing the orientation" of the window.
    • in the event "Move to the foreground" associated with the project.
      Remark: However, the function can be used in the event "Move to the foreground" of a window.
    • in a thread.
  • Android The position of the buttons varies according to the Android version. From Android 4.1, the system sets the validation button on the right. Dialog is used to define the position of the buttons, if necessary.

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.
YesNo can open a window. If this function is used while the application is in the background, a fatal error will occur.
  • 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.
Business / UI classification: UI Code
Component: wd270obj.dll
Minimum version required
  • Version 9
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Case 1


Case 2

18 Oct. 2021
Your documentation should go to trash, it is not possible to use YesNo in Browser, add a damn example, you only provide a skeletoon of the function but there are tons of users unable to use it. I never expect something from PCSOFT and I still get disapointed
Aldo Vargas
30 Apr. 2021