umainform.~pas

用DLL中封装MDI,在DLL文件中封装MDI

unit uMainForm;

interface

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

type
  PCallDllProc=^TCallDllProc;
  TCallDllProc=record
    HostAppHwnd:HWND;
    HostAppMainf:LongInt;
    HostScreen:LongInt;
    HostDataMdl:LongInt;
    Sql:string;
    wPower:Word;
    wParam:Integer;
    lParam:Integer;
    Reserved:Integer;
  end;

type
  TMainform = class(TAncestor)
    mm1: TMainMenu;
    H1: TMenuItem;
    t1: TMenuItem;
    ds1: TDataSource;
    dbgrd1: TDBGrid;
    qry1: TADOQuery;
    cds1: TClientDataSet;
    dsp1: TDataSetProvider;
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure FormDestroy(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

function InitDllForm1(CallDllProc:PCallDllProc):Integer;stdcall;

var
  Mainform: TMainform;


implementation

uses uDataMdl;

{$R *.dfm}

function InitDllForm1(CallDllProc:PCallDllProc):Integer;
var
  PtrMainf, PtrScr, PtrDataMdl:PLongint;
  Mf:TForm;
begin
  if not Assigned(Mainform) then begin
    with CallDllProc^ do begin
      Application.Handle:=HostAppHwnd;
      PtrMainf:=@(Application.MainForm);
      PtrMainf^:=HostAppMainf;
      PtrScr:=@Screen;
      PtrScr^:=HostScreen;
      Mf:=TForm(HostAppMainf);
    end;
    Mainform:=TMainform.Create(Mf);
    try
      Mainform.Show;
      Mainform.BringToFront;
      Mainform.qry1.SQL.Add(CallDllProc^.sql);
      Mainform.cds1.Active:=True;
    except
    end;
   end else
    Mainform.BringToFront;
end;

procedure TMainform.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  inherited;
  Action:=caFree;
end;

procedure TMainform.FormDestroy(Sender: TObject);
begin
  Mainform:=nil;
end;

procedure TMainform.FormCreate(Sender: TObject);
begin
  if (FormStyle=fsMDIChild) and (WindowState=wsNormal) then begin
    Position:=poDesigned;
    top:=(screen.WorkAreaHeight div 2) -(Height div 2)-100;
    Left:=(screen.WorkAreawidth div 2) -(Width div 2)
  end else if FormStyle<>fsMDIChild then
    Position:=poMainFormCenter;
end;

end.