Cross-Platform Change Tracking Data Bindings Example

Embarcadero

2 years ago

Edit field change tracking for data bindings

The Update Edit Field Demo is a great way to learn how to use data with Live Bindings. This cross-platform application makes it easy to bind the contents of an edit field with a label, using a single code base and single UI for Android, iOS, macOS, Windows, and Linux. It features change tracking so that on each key press the in-memory data set is updated with the change. With this demo, you’ll be able to quickly and easily update your labels with new data, keeping your user interface consistent across all platforms.

Download the full cross-platform change tracking data bindings 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.

Table of Contents

What is change tracking for data bindings in software development?

Change tracking is a process in software development whereby changes to data bindings are tracked. This enables developers to identify which parts of their codebase need to be updated when a change is made, and also allows for rollbacks if necessary. Change tracking can be done manually or using automation tools. In either case, it is an essential part of keeping a codebase maintainable and up-to-date. Without change tracking, it would be very difficult to manage any but the simplest of software projects.

Screenshot

What does the data binding source code look like for the edit field demo?

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs,
  FireDAC.Stan.Intf, FireDAC.Stan.Option, FireDAC.Stan.Param,
  FireDAC.Stan.Error, FireDAC.DatS, FireDAC.Phys.Intf, FireDAC.DApt.Intf,
  System.Rtti, System.Bindings.Outputs, Fmx.Bind.Editors, Data.Bind.EngExt,
  Fmx.Bind.DBEngExt, Data.Bind.Components, Data.Bind.DBScope, FMX.Edit, Data.DB,
  FireDAC.Comp.DataSet, FireDAC.Comp.Client, FMX.StdCtrls, FMX.Effects,
  FMX.Controls.Presentation, FireDAC.Stan.StorageBin;

type
  TForm1 = class(TForm)
    MaterialOxfordBlueSB: TStyleBook;
    ToolBar1: TToolBar;
    ShadowEffect4: TShadowEffect;
    Label1: TLabel;
    FDMemTable1: TFDMemTable;
    Edit1: TEdit;
    Label2: TLabel;
<strong>    BindSourceDB1: TBindSourceDB;
    BindingsList1: TBindingsList;
    LinkControlToField1: TLinkControlToField;
    LinkPropertyToFieldText: TLinkPropertyToField;
    procedure Edit1ChangeTracking(Sender: TObject);</strong>
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

<strong>procedure TForm1.Edit1ChangeTracking(Sender: TObject);
begin
  TLinkObservers.ControlChanged(Edit1);
end;</strong>

end.

unit Unit1;

interface

uses

System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,

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

FireDAC.Stan.Intf, FireDAC.Stan.Option, FireDAC.Stan.Param,

FireDAC.Stan.Error, FireDAC.DatS, FireDAC.Phys.Intf, FireDAC.DApt.Intf,

System.Rtti, System.Bindings.Outputs, Fmx.Bind.Editors, Data.Bind.EngExt,

Fmx.Bind.DBEngExt, Data.Bind.Components, Data.Bind.DBScope, FMX.Edit, Data.DB,

FireDAC.Comp.DataSet, FireDAC.Comp.Client, FMX.StdCtrls, FMX.Effects,

FMX.Controls.Presentation, FireDAC.Stan.StorageBin;

type

TForm1 = class(TForm)

MaterialOxfordBlueSB: TStyleBook;

ToolBar1: TToolBar;

ShadowEffect4: TShadowEffect;

Label1: TLabel;

FDMemTable1: TFDMemTable;

Edit1: TEdit;

Label2: TLabel;

<strong> BindSourceDB1: TBindSourceDB;

BindingsList1: TBindingsList;

LinkControlToField1: TLinkControlToField;

LinkPropertyToFieldText: TLinkPropertyToField;

procedure Edit1ChangeTracking(Sender: TObject);</strong>

private

{ Private declarations }

public

{ Public declarations }

end;

var

Form1: TForm1;

implementation

{$R *.fmx}

<strong>procedure TForm1.Edit1ChangeTracking(Sender: TObject);

begin

TLinkObservers.ControlChanged(Edit1);

end;</strong>

end.

What does the data bindings look like?

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