测试环境：XP,DELPHI XE

验证通过结构：主程序+一个Dll窗体

共享方式原理：通过主程序与各Dll定义相同的参数结构体，由主程序实例化该结构体，对于各Dll间的共享，通过传主程序实例化的结构体指针达到各Dll与主程序相互间的数据共享。且Dll释放不影响主程序实例化结构体时获得的内存空间

主程序代码：

unit Main_Unit;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;

type

  TPara = record

    ADOConnStr: String;

  end;

  TCreateFrm = procedure(AppHnd: THandle; APar: TPara); stdcall;		//此处传递主程序实例化后的参数结构体

  TCreateSubFrm = procedure(AppHnd: THandle); stdcall;

  TDropFrm = procedure; stdcall;

  TFrm_Main = class(TForm)

    Btn_1: TButton;

    Btn_2: TButton;

    Btn_3: TButton;

    Btn_4: TButton;

    Btn_5: TButton;

    Btn_6: TButton;

    Btn_7: TButton;    procedure Btn_1Click(Sender: TObject);

    procedure Btn_2Click(Sender: TObject);

    procedure Btn_3Click(Sender: TObject);

    procedure Btn_4Click(Sender: TObject);

    procedure Btn_5Click(Sender: TObject);

    procedure Btn_6Click(Sender: TObject);

    procedure Btn_7Click(Sender: TObject);

  private

    LibHandle: THandle;

    FormRef: LongInt;

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Frm_Main: TFrm_Main;

  APara: TPara;

implementation

{$R *.dfm}

procedure TFrm_Main.Btn_1Click(Sender: TObject);

begin

  if LibHandle = 0 then

  begin

    LibHandle := SafeLoadLibrary('SubMain.dll');

    if LibHandle = 0 then

      raise Exception.Create('Not Found Dll File')

    else

      ShowMessage('Dll Loaded');

  end;

end;

procedure TFrm_Main.Btn_2Click(Sender: TObject);

begin

  if LibHandle > 0 then

  begin

    FreeLibrary(LibHandle);

    LibHandle := 0;

    ShowMessage('Dll UnLoaded');

  end;

end;

procedure TFrm_Main.Btn_3Click(Sender: TObject);

var

  CreateFrm: TCreateFrm;

begin

  if LibHandle = 0 then

    raise Exception.Create('Place Load Dll File First');

  @CreateFrm := GetProcAddress(LibHandle,PChar('CreateFrm'));

  if @CreateFrm = nil then

    raise Exception.Create('Function Error');

  APara.ADOConnStr := 'Provider=SQLOLEDB.1;Password=*****;Persist Security Info=True;User ID=sa;Initial Catalog=test;Data Source=127.0.0.1';	//结构体赋值

  CreateFrm(Application.Handle,APara);

end;

procedure TFrm_Main.Btn_4Click(Sender: TObject);

var

  DropFrm: TDropFrm;

begin

  @DropFrm := GetProcAddress(LibHandle,PChar('DropFrm'));

  if @DropFrm = nil then

    raise Exception.Create('Function Error');

  DropFrm;

end;

procedure TFrm_Main.Btn_5Click(Sender: TObject);

var

  CreateSubFrm: TCreateSubFrm;

begin

  if LibHandle = 0 then

    raise Exception.Create('Place Load Dll File First');

  @CreateSubFrm := GetProcAddress(LibHandle,PChar('CreateSubFrm'));

  if @CreateSubFrm = nil then

    raise Exception.Create('Function Error');

  CreateSubFrm(Application.Handle);

end;

procedure TFrm_Main.Btn_7Click(Sender: TObject);

begin

  ShowMessage(APara.ADOConnStr);			//用来释放Dll后，验证结构体内存块是否同步被释放

end;

end.

Dll引用代码：

unit SubMain_Unit;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, DB, FyDataConn_Unit, ActiveX,

  ADODB, StdCtrls, cxGraphics, cxControls, cxLookAndFeels,

  cxLookAndFeelPainters, cxStyles, dxSkinsCore, dxSkinBlueprint,

  dxSkinDevExpressDarkStyle, dxSkinDevExpressStyle, dxSkinHighContrast,

  dxSkinSevenClassic, dxSkinSharpPlus, dxSkinStardust, dxSkinTheAsphaltWorld,

  dxSkinVS2010, dxSkinWhiteprint, dxSkinscxPCPainter, cxCustomData, cxFilter,

  cxData, cxDataStorage, cxEdit, cxNavigator, cxDBData, cxGridLevel, cxClasses,

  cxGridCustomView, cxGridCustomTableView, cxGridTableView, cxGridDBTableView,

  cxGrid, Grids, DBGrids,dxCore;

type

  TPara = record				//与主程序定义一个一样的结构体

    ADOConnStr: String;

  end;

  TPPara = ^TPara;				//定义该结构体的指针结构

  TFrm_SubMain = class(TForm)

    Btn_1: TButton;

    GTV_1: TcxGridDBTableView;

    GL_1: TcxGridLevel;

    Grd_1: TcxGrid;

    procedure FormClose(Sender: TObject; var Action: TCloseAction);

    procedure FormDestroy(Sender: TObject);

    procedure Btn_1Click(Sender: TObject);

    procedure FormCreate(Sender: TObject);

  private

    DSet: TADODataSet;

    DS: TDataSource;

    Conn: TADOConnection;

    { Private declarations }

  public

    { Public declarations }

  end;

  procedure CreateFrm(AppHnd: THandle; APar: TPara);export;stdcall;

  procedure DropFrm; export;stdcall;

var

  Frm_SubMain: TFrm_SubMain;

  LocPara: TPara;

  PPara: TPPara;

implementation

{$R *.dfm}

procedure CreateFrm(AppHnd: THandle; APar: TPara);

begin

  Application.Handle := AppHnd;

  PPara := @APar;		//直接

  if not Assigned(Frm_SubMain) then

    Frm_SubMain := TFrm_SubMain.Create(Application);

  Frm_SubMain.Show;

end;

procedure DropFrm;

begin

  if Frm_SubMain <> nil then

    FreeAndNil(Frm_SubMain);

end;

procedure TFrm_SubMain.Btn_1Click(Sender: TObject);

var

  SQL: String;

begin

  DSet.Connection := Conn;

  DS.DataSet := DSet;

  SQL := 'Select * From Cg_CgDanSub';

  dbOpen(SQL,DSet);       //自定义函数，用于打开数据集

  GTV_1.DataController.DataSource := DS;

  (GTV_1.DataController as IcxCustomGridDataController).DeleteAllItems;           //清除cxGrid列

  (GTV_1.DataController as IcxCustomGridDataController).CreateAllItems(False);    //添加cxGrid列

end;

procedure TFrm_SubMain.FormClose(Sender: TObject; var Action: TCloseAction);

begin

  Action := caFree;

end;

procedure TFrm_SubMain.FormCreate(Sender: TObject);

begin

  Conn := TADOConnection.Create(Application);

  Conn.LoginPrompt := False;

  Conn.ConnectionString := PPara.ADOConnStr;

  //Conn.ConnectionString := 'Provider=SQLOLEDB.1;Password=fydesign;Persist Security Info=True;User ID=sa;Initial Catalog=test;Data Source=127.0.0.1';

  Conn.Connected := True;

  DSet := TADODataSet.Create(Application);

  DS := TDataSource.Create(Application);

end;

procedure TFrm_SubMain.FormDestroy(Sender: TObject);

begin

  DSet.Free;

  DS.Free;

  FreeAndNil(Conn);

  Frm_SubMain := nil;

end;

initialization

  dxInitialize;

finalization

  dxFinalize;

end.