TQThread = class(TThread)
  private
    FQuery: TADOQuery;
    FDataSource: TDataSource;
    FIsRunning: Boolean;
    FRecordCount: Integer;

    function GetIsRunning: Boolean;

    procedure DisableFormControls;
    procedure EnableFormControls;
  protected
    procedure Execute; override;

  public
    constructor Create(DataSource: TDataSource);
    destructor Destroy; override;

  published
    property IsRunning: Boolean read GetIsRunning;
    property RecordCount: Integer read FRecordCount write FRecordCount;
  end;


constructor TQThread.Create(DataSource: TDataSource);
begin
  FDataSource := DataSource;
  FQuery := TADOQuery(FDataSource.DataSet);
  FreeOnTerminate := True;

  inherited Create(True);
end;

destructor TQThread.Destroy;
begin
  FreeAndNil(FQuery);

  inherited;
end;

procedure TQThread.DisableFormControls;
begin
  FDataSource.DataSet.DisableControls;
end;

procedure TQThread.EnableFormControls;
begin
  FDataSource.DataSet.EnableControls;
end;

procedure TQThread.Execute;
begin
  inherited;

  try
    try
      FIsRunning := True;
      RecordCount := 0;

      Synchronize(DisableFormControls);

      FQuery.Close;
      FQuery.Open;

      FQuery.Last;
      FQuery.First;

      RecordCount := FQuery.RecordCount;
    except
      on Ex: Exception do
      begin
        dxMessageDlg('Fehler beim Ausführen des Query-Thead! (' + FQuery.Name + ', ' + Self.QualifiedClassName + ')' + #13#10#13#10 + 'Fehlermeldung: ' + Ex.Message + #13#10 + Ex.StackTrace + #13#10 + 'SQL: ' + FQuery.SQL.Text, mtError, [mbOK], 0);
      end;
    end;
  finally
    if not Terminated then
    begin
      Synchronize(EnableFormControls);
      FIsRunning := False;
    end;
  end;
end;

function TQThread.GetIsRunning: Boolean;
begin
  Result := FIsRunning;
end;