unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ComCtrls, StdCtrls, ExtCtrls, Grids, Wwdbigrd, Wwdbgrid, DBCtrls,
  SUIForm, SUIPageControl, SUITabControl, Buttons, SUIImagePanel, ToolWin,
  DB, ADODB, wwriched,ActiveX, ImgList;

type
  TDragAndDropOLE=Class(TObject,IUnknown,IDropTarget)
  private
   CanDrop:HResult;
   fe:TFormatEtc;//數(shù)據(jù)的格式，在實(shí)現(xiàn)部分給出詳細(xì)說(shuō)明
   FRefCount:integer;//引用計(jì)數(shù)
  protected
   { Iunkown }
   function _AddRef:integer;stdcall;
   function _Release:integer;stdcall;
   function QueryInterface(const IID:TGUID;out Obj):HResult;stdcall;
   { IdropTarget }
   function DragEnter(const dataObj: IDataObject; grfKeyState: Longint;
      pt: TPoint; var dwEffect: Longint): HResult;stdcall;
   function DragOver(grfKeyState: Longint; pt: TPoint;var dwEffect: Longint):HResult;stdcall;
   function DragLeave: HResult;stdcall;
   function Drop(const dataObj: IDataObject; grfKeyState: Longint; pt: TPoint;
    var dwEffect: Longint): HResult; stdcall;
  public
   constructor Create;
   destructor Destroy;override;
  end;

type
  TForm1 = class(TForm)
    suiForm1: TsuiForm;
    suiPageControl1: TsuiPageControl;
    suiTabSheet1: TsuiTabSheet;
    suiTabSheet2: TsuiTabSheet;
    suiPanel1: TsuiPanel;
    lbl1: TLabel;
    edt1: TEdit;
    btn1: TSpeedButton;
    suiPanel2: TsuiPanel;
    wwDBGrid1: TwwDBGrid;
    spl1: TSplitter;
    dbmmo1: TDBMemo;
    lbl2: TLabel;
    suiPanel3: TsuiPanel;
    tlb1: TToolBar;
    btn2: TToolButton;
    btn3: TToolButton;
    btn4: TToolButton;
    btn5: TToolButton;
    btn6: TToolButton;
    btn7: TToolButton;
    btn8: TToolButton;
    dbmmo2: TDBMemo;
    spl2: TSplitter;
    dbmmo3: TDBMemo;
    lbl3: TLabel;
    ds1: TADODataSet;
    ds2: TDataSource;
    ImageList1: TImageList;
    procedure btn2Click(Sender: TObject);
    procedure btn3Click(Sender: TObject);
    procedure btn4Click(Sender: TObject);
    procedure btn5Click(Sender: TObject);
    procedure btn6Click(Sender: TObject);
    procedure btn7Click(Sender: TObject);
    procedure btn8Click(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure btn1Click(Sender: TObject);
  private
    DragAndDropOLE:TDragAndDropOLE;
  public
    constructor Create(AOwner: TComponent);override;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

constructor TDragAndDropOLE.Create;
begin
  FRefCount:=0;
  RegisterDragDrop(Form1.dbmmo2.Handle,self);//上文提到的函數(shù)
  RegisterDragDrop(Form1.dbmmo3.Handle,self);//上文提到的函數(shù)
end;

destructor TDragAndDropOLE.Destroy;
begin
  RevokeDragDrop(Form1.dbmmo2.Handle);
  RevokeDragDrop(Form1.dbmmo3.Handle);
  inherited;
end;

//接下來(lái)實(shí)現(xiàn)Iunknown，不再做詳細(xì)說(shuō)明：
function TDragAndDropOLE._AddRef: integer;
begin
 result:=InterLockedDecrement(FRefCount);
 if Result=0 then Destroy;
end;
 
function TDragAndDropOLE._Release: integer;
begin
 result:=InterLockedIncrement(FRefCount);
end;
 
function TDragAndDropOLE.QueryInterface(const IID: TGUID;
  out Obj): HResult;
begin
 if GetInterface(IID,Obj) then
  result:=S_OK
 else result:=E_NOINTERFACE;
end;

//最重要的IDropTarget實(shí)現(xiàn)：
function TDragAndDropOLE.DragEnter(const dataObj: IDataObject;
  grfKeyState: Integer; pt: TPoint; var dwEffect: Integer): HResult;
begin
 result:=E_FAIL;
 CanDrop:=E_Fail;
 if assigned(dataObj) then
 begin
  with fe do
  begin
   cfFormat:=CF_TEXT;
   ptd:=nil;
   dwAspect:=DVASPECT_CONTENT;
   lindex:=-1;
   tymed:=TYMED_HGLOBAL;
  end;
  //大家從上面看到的fe是一種我們處理內(nèi)存數(shù)據(jù)時(shí)常用的轉(zhuǎn)換格式
  //這里它表示將數(shù)據(jù)格式作為文字（cfFormat），并將其存入一塊
  //全局的內(nèi)存區(qū)域（tymed:=TYMED_HGLOBAL），更多的格式請(qǐng)?jiān)趙in32
  //幫助中搜索TFormatEtc
  CanDrop:=dataObj.QueryGetData(fe);//按照f(shuō)e指定的格式檢查數(shù)據(jù)
  result:=CanDrop;
  if not Failed(result) then
   dwEffect:=DROPEFFECT_COPY
  else dwEffect:=DROPEFFECT_NONE;
  //注意這里我們?cè)O(shè)置了dwEffect,更多的取值請(qǐng)查看win32幫助
 end;
end;
 
function TDragAndDropOLE.DragLeave: HResult;
begin
 result:=S_OK;
end;
 
function TDragAndDropOLE.DragOver(grfKeyState: Integer; pt: TPoint;
  var dwEffect: Integer): HResult;
begin
 result:=S_OK;
 //我們不需要在這里做其余的操作，當(dāng)然你可以根據(jù)自己的需要完成自己的方法
end;
 
function TDragAndDropOLE.Drop(const dataObj: IDataObject;
  grfKeyState: Integer; pt: TPoint; var dwEffect: Integer): HResult;
var
 medium:stgMedium;
 hData:HGLOBAL;
 handle:THandle;
begin
 result:=E_Fail;
 if not Failed(CanDrop) then
 begin
   result:=dataObj.GetData(fe,medium);
   //按照f(shuō)e的格式將數(shù)據(jù)存入內(nèi)存的一塊全局區(qū)域，注意medium
   hData:=HGLOBAL(GlobalLock(medium.hGlobal));
   //GlobalLock鎖定這塊區(qū)域，并返回指向它的指針
   handle:=WindowFromPoint(pt);
   if Form1.dbmmo2.Handle=handle then
     Form1.dbmmo2.Text:=pchar(hData)
   else
     Form1.dbmmo3.Text:=pchar(hData);
   GlobalUnlock(hData);//接觸鎖定
   GlobalFree(hData);//釋放
 end;
end;

constructor TForm1.Create(AOwner: TComponent);
begin
  inherited Create(AOWner);
  OleInitialize(nil);
  DragAndDropOLE:=TDragAndDropOLE.Create;
  // TDragAndDropOLE便是我們要實(shí)現(xiàn)IDropTarget接口的類
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  DragAndDropOLE.Free;
  OleUninitialize;
  inherited;
end;

procedure TForm1.btn2Click(Sender: TObject);
begin
    ds1.Append;
end;

procedure TForm1.btn3Click(Sender: TObject);
begin
  ds1.Post;
end;

procedure TForm1.btn4Click(Sender: TObject);
begin
  ds1.Delete;
end;

procedure TForm1.btn5Click(Sender: TObject);
begin
  ds1.First;
end;

procedure TForm1.btn6Click(Sender: TObject);
begin
  ds1.Prior;
end;

procedure TForm1.btn7Click(Sender: TObject);
begin
  ds1.Next;
end;

procedure TForm1.btn8Click(Sender: TObject);
begin
  ds1.Last;
end;

procedure TForm1.btn1Click(Sender: TObject);
begin
    ds1.Close;
    ds1.CommandText:='select * from 題目 where 題目 like ''%'+edt1.Text+'%''';
    ds1.Open;
end;

end.