Delphi Spinedit: Get the previous value

Question

Lets say I have a Spinedit on my Form.

The current Value of the Spinedit is e.g 5

When the user clicks on the SpinButton the next Value could be

4 or 6.

In the onChange event

I can get the new Value

4 or 6

but I need to know also the old Value

5

How can I get the previous value 5 in Delphi?

I need to know the old and the new Value

Answer 1

Store the previous value in a variable at the end of the OnChange event and at startup as below.

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.Samples.Spin;

type
  TForm1 = class(TForm)
    SpinEdit1: TSpinEdit;
    procedure SpinEdit1Change(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
    FSpinPrev : Integer;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  FSpinPrev := SpinEdit1.Value;
end;

procedure TForm1.SpinEdit1Change(Sender: TObject);
begin
  if SpinEdit1.Value > FSpinPrev then Caption := 'Increasing'
                                 else Caption := 'Decreasing';

  FSpinPrev := SpinEdit1.Value;
end;

end.