OnChange Event Tracking Demo For Windows And Mobile

Embarcadero

vor 2 Jahren

OnChange Tracking Event Demo | Learn Delphi

OnChange Tracking Demo is the perfect way to learn how to build a demo that handles an OnChange event. This cross-platform application is built in Delphi using a single code base and single UI for Android, iOS, macOS, Windows, and Linux. With OnChange Tracking Demo, you’ll be able to quickly and easily create a demo that tracks changes in data. This is an essential tool for anyone who wants to learn how to build demos or for developers who need to track changes in their data. OnChange Tracking Demo is the perfect solution for tracking changes in data on any platform.

Download the full cross-platform Hello World source code on Github.

This demo is part of over 100 cross-platform demos with everything from camera demos to emoji demos and painting demos.

Inhaltsverzeichnis

What is an OnChange event in software development?

In software development, an OnChange event is an event that occurs when the value of a field changes. This can be due to the user changing the value manually, or programmatically through code. When the OnChange event fires, it allows the software to run any necessary code to update other parts of the software accordingly. For example, if a software application has a field for entering a user’s email address, the OnChange event could be used to check that the email address is valid before the user submits the form. In this way, OnChange events can help to ensure that software operates as intended.

Screenshot

What does the sample code look like?

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.Edit,
  FMX.Effects, FMX.StdCtrls, FMX.Controls.Presentation;

type
  TForm1 = class(TForm)
    ToolBar1: TToolBar;
    Label1: TLabel;
    ShadowEffect4: TShadowEffect;
    MaterialOxfordBlueSB: TStyleBook;
    Edit1: TEdit;
    procedure Edit1ChangeTracking(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

procedure TForm1.Edit1ChangeTracking(Sender: TObject);
begin
  Label1.Text := Edit1.Text;
end;

end.

unit Unit1;

interface

uses

System.SysUtils, System.Types, System.UITypes, System.Klassen, System.Variants,

FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.Edit,

FMX.Effects, FMX.StdCtrls, FMX.Controls.Presentation;

type

TForm1 = Klasse(TForm)

ToolBar1: TToolBar;

Label1: TLabel;

ShadowEffect4: TShadowEffect;

MaterialOxfordBlueSB: TStyleBook;

Edit1: TEdit;

procedure Edit1ChangeTracking(Sender: TObject);

private

{ Private declarations }

public

{ Public declarations }

end;

var

Form1: TForm1;

implementation

{$R *.fmx}

procedure TForm1.Edit1ChangeTracking(Sender: TObject);

Start

Label1.Text := Edit1.Text;

end;

end.

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