Refresh DBGrid from another form in delphi

Question

I'm just beginning to learn Delphi and I've a problem. I'd refresh DBGrid from another form. My code:

Form1:

unit uForm1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, ADODB, Grids, DBGrids, StdCtrls;

type
  TForm1 = class(TForm)
    btnAdd: TButton;
    grid: TDBGrid;
    ADOQuery1: TADOQuery;
    DataSource1: TDataSource;
    procedure btnAdd(Sender: TObject);
  private
  public
       constructor Create(Owner:TComponent); overload;
  end;

var
  form1: TForm1;

implementation

uses uForm2, uDbOperations;

{$R *.dfm}

procedure TForm1.btnAddClick(Sender: TObject);
var
  frm : TForm2;
begin
  frm := TForm2.Create(form1);
  frm.ShowModal;
  frm.Free;
end;

Form2:

unit uForm2;
procedure TForm2.btnAddClick(Sender: TObject);
var
  query : string;
begin
       query := 'Insert into Employees(Name) Values('''+txtName.Text+''');';
       DbOperations.InsertOrUpdate(query, ADOQuery1);
        ModalResult := mrCancel;
        //And this here I'd refresh grid on form1           
end;
end.

How I can after add record in form2, refresh dbgrid in form1? I've tried many ways, but without success. I know that in C# need pass reference in constructor, but delphi how?

Answer 1

Using your pattern, I would do something like this:

procedure TForm1.btnAddClick(Sender: TObject);
var
  frm : TForm2;
begin
  frm := TForm2.Create(form1);
  try
    if frm.ShowModal = mrOK then
    begin
      Grid.Datasource.Dataset.Refresh;
      // some databases require open/close to refresh
      // in this case Grid.Datasource.Dataset.close;
      //              Grid.Datasource.Dataset.Open;
    end;
  finally
    frm.Free;
  end
end;

procedure TForm2.btnAddClick(Sender: TObject);
var
  query : string;
begin
  query := 'Insert into Employees(Name) Values('''+txtName.Text+''');';
  DbOperations.InsertOrUpdate(query, ADOQuery1);
  ModalResult := mrOK;
  // let a cancel button on Form2 perform ModalResult = mrCancel  
  // to avoid unnecessary dataset refreshes..      
end;