procedure TForm1.DBNavigator1Click(Sender: TObject; Button: TNavigateBtn);
begin
    if Button = nbInsert then
    begin
    Table1.Append;
    abort;
    end
end;

或者：

procedure TForm1.DBNavigator1Click(Sender: TObject; Button: TNavigateBtn);
begin
    if Button = nbInsert then begin
    Query1.Cancel;
    Query1.Append;
    end;
end;