Delphi - Correctly displaying a Message Dialog in FireMonkey and returning the Modal Result

Question:

It does not show the 2 buttons (Yes, Cancel). Could someone please help me get this right - i.e. correctly show the message dialog with the 2 buttons and send the modal result of the message dialog back as the Result of the function.

The Fmx.TDialogService.MessageDialog does not support arbitrary combinations of dialog buttons.

Looking into the source code (Fmx.Dialogs.Win.pas) reveals these valid combinations (mbHelp can be included in all combinations):

• mbOk
• mbOk,mbCancel
• mbYes,mbNo,mbCancel
• mbYes, mbYesToAll, mbNo, mbNoToAll, mbCancel
• mbAbort, mbRetry, mbIgnore
• mbAbort, mbIgnore
• mbYes, mbNo
• mbAbort, mbCancel

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This means that [mbYes,mbCancel] is not a valid combination, use [mbOk,mbCancel] instead for example.

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A final note about the Fmx.TDialogService.MessageDialog. It is normally a synchronous dialog on desktop applications, but asynchronous on mobile platforms. The use case will look a bit different depending on those conditions, so for a multi-platform application, check the value of TDialogService.PreferredMode.

Hi friend try this code:

function myMessageDialog(const AMessage: string; const ADialogType: TMsgDlgType;
  const AButtons: TMsgDlgButtons; const ADefaultButton: TMsgDlgBtn): Integer;
var
  mr: TModalResult;
begin
  mr:=mrNone;
  // standart call with callback anonimous method
  TDialogService.MessageDialog(AMessage, ADialogType, AButtons,
    ADefaultButton, 0,
    procedure (const AResult: TModalResult) 
    begin 
      mr:=AResult 
    end);

  while mr = mrNone do // wait for modal result
    Application.ProcessMessages;
  Result:=mr;
end;

Or this:

function MsgBox(const AMessage: string; const ADialogType: TMsgDlgType; const AButtons: TMsgDlgButtons;
    const ADefaultButton: TMsgDlgBtn ): Integer;
var
    myAns: Integer;
    IsDisplayed: Boolean;
begin
    myAns := -1;
    IsDisplayed := False;

While myAns = -1 do
Begin
    if IsDisplayed = False then
    TDialogService.MessageDialog(AMessage, ADialogType, AButtons, ADefaultButton, 0,
            procedure (const AResult: TModalResult)
            begin
                myAns := AResult;
                IsDisplayed := True;
            end);

    IsDisplayed := True;
    Application.ProcessMessages;
End;

Result := myAns;

end;

Enjoy it!