Retornar código gerado de campo autoincremento para a tela, utilizando DBExpress. Automatizando processos com TFieldDataLink.

Unit Text;

Interface

Uses
   StdCtrls, Classes, DB, DBCtrls;

Type
  TText = Class(TEdit)
  Private
    FFieldLink:TDataFieldLink;
  Public
    Constructor Create(AOwner:TComponent); Override;
    Destructor Destroy(); Override;
  Protected
    Procedure KeyPress(var Key:Char); Override;
  Private
    Procedure ProximoCampo;
    Procedure CampoAnterior;
    Procedure DataChange(Sender:TObject);
    Procedure OnFieldLinkActivate(Sender:TObject);
  Protected
    Function GetDataField: WideString;
    Procedure SetDataField(Value: WideString);
    Function GetDataSource: TDataSource;
    Procedure SetDataSource(Value: TDataSource);
  Published
    Property DataField:WideString   Read GetDataField  Write SetDataField;
    Property DataSource:TDataSource Read GetDataSource Write SetDataSource;
  End;


Procedure Register;

Implementation

Uses
   Windows, Messages, Controls, SysUtils;

Procedure Register;
Begin
  RegisterComponents('FWEdits', [TText]);
End;

{ TText }

// Constructor & Destructor ------------------------------------------------- //

Constructor TText.Create(AOwner: TComponent);
Begin
   Inherited Create(AOwner);

   ControlStyle := ControlStyle + [csReplicatable];

   FFieldLink := TDataFieldLink.Create;
   FFieldLink.Control := Self;
   FFieldLink.OnDataChange := DataChange;
   FFieldLink.OnActiveChange := OnFieldLinkActivate;
   Inherited ReadOnly := ( DataSource <> Nil );
End;

Destructor TText.Destroy;
Begin
   FreeAndNil(FFieldLink);
   Inherited;
End;

// Métodos Protected's Herdados da Classe Pai ------------------------------- //

Procedure TText.KeyPress(var Key:Char);
Begin
   Inherited;

   If ( Key = #13 ) Then
      Begin
         Key := #0;
         ProximoCampo;
      End;

   If ( Key = #27 ) Then
      Begin
         Key := #0;
         CampoAnterior;
      End;
End;

// Métodos Privates Implementados ------------------------------------------- //

Procedure TText.ProximoCampo;
Begin
   SendMessage( Self.Parent.Handle, WM_NEXTDLGCTL, 0, 0 );
End;

Procedure TText.CampoAnterior;
Begin
   SendMessage( Self.Parent.Handle, WM_NEXTDLGCTL, 0, 1 );
End;

Procedure TText.DataChange(Sender:TObject);
Begin
   If ( FFieldLink.DataSource <> Nil ) And ( FFieldLink.Field = Nil ) Then
      If Not( FFieldLink.DataSource.State In [dsEdit,dsInsert] ) Then
         Begin
            Text := FFieldLink.Field.DisplayText;
         End;
End;

Procedure TText.OnFieldLinkActivate(Sender: TObject);
Begin
   If FFieldLink.Field <> Nil Then
      Begin

         Alignment := FFieldLink.Field.Alignment;
         MaxLength := FFieldLink.Field.Size;
      End
   Else
      Begin
         Alignment := taLeftJustify;
      End;
End;

// Métodos de Propriedades Implementadas ------------------------------------ //

Procedure TText.SetDataField(Value: WideString);
Begin
   FFieldLink.FieldName := Value;
   OnFieldLinkActivate(Self);
End;

Function TText.GetDataField: WideString;
Begin
   Result := FFieldLink.FieldName;
End;

Procedure TText.SetDataSource(Value: TDataSource);
Begin
   If FFieldLink.DataSource <> Value Then
      FFieldLink.DataSource := Value;
End;

Function TText.GetDataSource: TDataSource;
Begin
   Result := FFieldLink.DataSource;
End;

End.

Unit Unit1;

Interface

Uses
  Forms, Controls, StdCtrls, Classes, Text, Grids, DBGrids, DB, DBClient,
  SimpleDS, DBXFirebird, ExtCtrls, DBCtrls;

type
  TForm1 = Class(TForm)
    Text1: TText;
    Label1: TLabel;
    Text2: TText;
    Label2: TLabel;
    Text3: TText;
    Label3: TLabel;
    DBGrid1: TDBGrid;
    Adicionar: TButton;
    SDSTeste: TSimpleDataSet;
    DtsTeste: TDataSource;
    procedure AdicionarClick(Sender: TObject);
    procedure FormShow(Sender: TObject);
  Private
  Public
  End;

var
  Form1: TForm1;

Implementation

Uses
   Dialogs;

{$R *.dfm}

Procedure TForm1.FormShow(Sender: TObject);
Begin
   SdsTeste.CreateDataSet;
End;

Procedure TForm1.AdicionarClick(Sender: TObject);
var nI:Integer;
Begin
  SdsTeste.Append;

  For nI := 0 To (Self.ComponentCount-1) Do
     Begin

        If Self.Components[nI] Is TText Then
           SDSTeste.FieldByName( TText( Self.Components[nI] ).DataField ).Text :=
              TText( Self.Components[nI] ).Text;
     End;

  SdsTeste.Post;
  SdsTeste.ApplyUpdates(0);

  ShowMessage( SDSTeste.FieldByName('Codig_Prod').AsString );
End;

End.