DW.VCL.DBControl.pas

unit DW.VCL.DBControl;

interface

uses
  Classes, System.SysUtils, DW.VCL.Control, DB, DWElementTag, DW.VCL.DataLink;

type
  // Base class for DW data aware controls
  TDWCustomDbControl = class(TDWInputControl)
  private
    FMaxLength: Integer;
    procedure SetMaxLength(const AValue: Integer);
  protected
    FDataLink: TDWDataLink;
    FDataField: string;
    FDataSource: TDataSource;
    procedure CheckData; virtual;
    procedure Notification(AComponent: TComponent; AOperation: TOperation); override;
    procedure SetDataField(const AValue: string); virtual;
    procedure SetDataSource(const Value: TDataSource); virtual;
    property MaxLength: Integer read FMaxLength write SetMaxLength;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    procedure InternalRenderCss(var ACss: string); override;
    function RenderAsync: TDWElementXHTMLTag; override;
    function RenderHTML: TDWElementTag; override;
  published
    property DataSource: TDataSource read FDataSource write SetDataSource;
    property DataField: string read FDataField write SetDataField;
  end;

implementation

uses
  DWUtils;
{ TIWBSCustomDbControl }

procedure TDWCustomDbControl.CheckData;
begin
  //
end;

constructor TDWCustomDbControl.Create(AOwner: TComponent);
begin
  inherited;
  FDataLink  := nil;
  FDataField := '';
end;

destructor TDWCustomDbControl.Destroy;
begin
  FreeAndNil(FDataLink);
  inherited;
end;

procedure TDWCustomDbControl.InternalRenderCss(var ACss: string);
begin
  inherited;

end;

procedure TDWCustomDbControl.Notification(AComponent: TComponent; AOperation: TOperation);
begin
  inherited Notification(AComponent, AOperation);
  if AOperation = opRemove then
    if FDataSource = AComponent then
      SetDataSource(nil);
end;

function TDWCustomDbControl.RenderAsync: TDWElementXHTMLTag;
begin
  CheckData;
  Result := inherited;
end;

function TDWCustomDbControl.RenderHTML: TDWElementTag;
begin
  CheckData;
  Result := inherited;
end;

procedure TDWCustomDbControl.SetDataField(const AValue: string);
var
  xFld: TField;
begin
  if not SameText(AValue, FDataField) then
    begin
      FDataField := AValue;
      MaxLength  := 0;
      if FDataField <> '' then
        begin
          xFld := GetDataSourceField(FDataSource, FDataField);
          if Assigned(xFld) and (xFld is TStringField) then
            MaxLength := TStringField(xFld).Size;
        end;
      Invalidate;
    end;
end;

procedure TDWCustomDbControl.SetDataSource(const Value: TDataSource);
begin
  if Value <> FDataSource then
    begin
      FDataSource := Value;
      if Value = nil then
        begin
          FDataField := '';
          FreeAndNil(FDataLink);
        end
      else
        begin
          if FDataLink = nil then
            FDataLink          := TDWDataLink.Create(Self);
          FDataLink.DataSource := FDataSource;
        end;
      Invalidate;
    end;
end;

procedure TDWCustomDbControl.SetMaxLength(const AValue: Integer);
begin
  if FMaxLength <> AValue then
    begin
      FMaxLength := AValue;
      AsyncRefreshControl;
    end;
end;

end.