DevExpress (DEXT) Components — Skill

Use this skill when developing rich interfaces with DevExpress (DEXT) components for Delphi VCL.

When to Use

• When creating advanced grids with TcxGrid
• When using TcxDBTreeList for hierarchical structures
• When implementing layout managers (TdxLayoutControl)
• When customizing skins and themes

Main Components

TcxGrid Configuration

//Programmatic column creation
procedure TfrmCustomerList.ConfigureGrid;
var
  LView: TcxGridDBTableView;
begin
  LView := grdCustomers.Views[0] as TcxGridDBTableView;
  LView.DataController.DataSource := dsCustomers;

  //Configure behavior
  LView.OptionsData.Editing := False;        //Read only
  LView.OptionsData.Deleting := False;
  LView.OptionsData.Inserting := False;
  LView.OptionsView.GroupByBox := True;       //Visual grouping
  LView.OptionsView.Footer := True;          //Footer with summaries
  LView.OptionsView.Indicator := True;       //Line indicator
  LView.OptionsCustomize.ColumnFiltering := True;
  LView.OptionsCustomize.ColumnSorting := True;
  LView.OptionsSelection.MultiSelect := True;

  //Configure columns individually
  ConfigureColumn(LView.GetColumnByFieldName('name'), 'Nome', 200);
  ConfigureColumn(LView.GetColumnByFieldName('cpf'), 'CPF', 120);
  ConfigureColumn(LView.GetColumnByFieldName('email'), 'E-mail', 250);
end;

procedure TfrmCustomerList.ConfigureColumn(
  AColumn: TcxGridDBColumn; const ACaption: string; AWidth: Integer);
begin
  if not Assigned(AColumn) then Exit;
  AColumn.Caption := ACaption;
  AColumn.Width := AWidth;
  AColumn.HeaderAlignmentHorz := taCenter;
end;

Summaries in the Grid

//Footer Summary
procedure ConfigureFooterSummary(AView: TcxGridDBTableView);
var
  LSummary: TcxGridDBTableSummaryItem;
begin
  AView.DataController.Summary.FooterSummaryItems.Clear;

  LSummary := AView.DataController.Summary.FooterSummaryItems.Add
    as TcxGridDBTableSummaryItem;
  LSummary.FieldName := 'value';
  LSummary.Kind := skSum;
  LSummary.Format := 'Total: R$ #,##0.00';
  LSummary.Column := AView.GetColumnByFieldName('value');

  LSummary := AView.DataController.Summary.FooterSummaryItems.Add
    as TcxGridDBTableSummaryItem;
  LSummary.FieldName := 'id';
  LSummary.Kind := skCount;
  LSummary.Format := 'Registros: %d';
  LSummary.Column := AView.GetColumnByFieldName('name');
end;

TdxLayoutControl (Responsive Layout)

//Form organization with LayoutControl
//Advantages: responsive, automatically repositions, consistent look

procedure TfrmCustomerEdit.ConfigureLayout;
begin
  lytMain.BeginUpdate;
  try
    //Personal data group
    lgrpPersonal.Caption := 'Dados Pessoais';
    lgrpPersonal.LayoutDirection := ldHorizontal;

    //Address group
    lgrpAddress.Caption := 'Endereço';
    lgrpAddress.LayoutDirection := ldHorizontal;

    //Configure items
    litmName.Control := edtName;
    litmName.CaptionOptions.Text := 'Nome:';
    litmName.CaptionOptions.Width := 80;
  finally
    lytMain.EndUpdate;
  end;
end;

Skinning / Themes

//Apply skin globally
uses
  dxSkinsCore,
  dxSkinOffice2019Colorful;  //Specific skin

procedure TfrmMain.ApplySkin;
begin
  //Via SkinController (recommended)
  sknController.NativeStyle := False;
  sknController.SkinName := 'Office2019Colorful';

  //OR programmatically
  cxLookAndFeelController.NativeStyle := False;
  cxLookAndFeelController.SkinName := 'Office2019Colorful';
end;

//Skins populares: 'Office2019Colorful', 'WXI', 'Metropolis',
//'MetropolisDark', 'TheBezier', 'Fluent', 'Office2019DarkGray'

Filters in the Grid

//Programmatic filter
procedure TfrmCustomerList.ApplyFilter(const AField, AValue: string);
var
  LView: TcxGridDBTableView;
begin
  LView := grdCustomers.Views[0] as TcxGridDBTableView;
  LView.DataController.Filter.Root.Clear;
  LView.DataController.Filter.Root.AddItem(
    LView.GetColumnByFieldName(AField),
    foLike,
    '%' + AValue + '%',
    AValue
  );
  LView.DataController.Filter.Active := True;
end;

//Clean filter
procedure TfrmCustomerList.ClearFilter;
begin
  (grdCustomers.Views[0] as TcxGridDBTableView)
    .DataController.Filter.Root.Clear;
end;

Grid Export

uses
  cxGridExportLink;

//Export to Excel
procedure TfrmCustomerList.ExportToExcel;
begin
  cxGridExportLink.ExportGridToXLSX(
    'customers.xlsx',
    grdCustomers,
    False,   // AExpand
    True,    //AUseNativeFormat
    True     //AShowProgress
  );
end;

//Export to PDF
procedure TfrmCustomerList.ExportToPDF;
begin
  cxGridExportLink.ExportGridToPDF(
    'customers.pdf',
    grdCustomers
  );
end;

DEXT Conventions

Checklist for DEXT Projects

• TdxSkinController configured in the main form?
• Grids configured with OptionsData (read-only when appropriate)?
• Footer summaries configured with BR formats (R$ #,##0.00)?
• TdxLayoutControl used for editing forms?
• Grid columns with Caption, Width and Alignment?
• Filters using DataController.Filter (not SQL)?
• Export via cxGridExportLink?
• Component prefixes following the standard table?