利用Delphi編寫IE擴充套件 (轉)

worldblog發表於2007-12-04
利用Delphi編寫IE擴充套件 (轉)[@more@]

就是如何使IE擴充套件可以響應事件。
  在自己的中使用過Browser的朋友都知道,WebBrowser控制元件定義了諸如BeforeNavigate、Complete 等事件,我們可以透過編寫事件處理程式碼實現對WebBrowser控制元件的操作。那麼如何實現對IE的事件響應和處理呢?同建立IE皮膚一樣。我們需要建立一個實現IWithSite介面的COM元件,不同的是,我們還需要實現IDispatch介面,在IObjectWithSite介面的SetSite方法中獲得IE的WebBrowser介面並建立自身與WebBrowser的連線,然後如果在IE的Webbrowser中發生什麼事件的話,那麼IE就會回撥連線的IDispatch介面的Invoke方法。我們透過在Invoke方法中編寫程式碼就可以獲得IE事件了。這個利用的是COM的回撥介面原理。
  下面我們首先來實現程式碼。點選選單 File | New 。在 頁面中選擇Active Library ,然後點選 OK 按鈕。然後用同樣的方法建立一個Object。在COM Object Wizard 視窗中,將核取方塊 Included type library 去掉。然後在Class Name中輸入IEHelper,在Implemented Interface 中輸入:IDispatch;IObjectwithSite 。然後點選 OK 按鈕建立一個COM元件。
  儲存工程,將工程儲存為IEHelper.dpr,將Unit1儲存為IEHelperUnit.pas。下面是IEHelperUnit.pas的具體程式碼:

unit iehelperunit;

interface

uses
, Comobj, ActiveX, SHDOCVW, MSHTML,Dialogs;


type

  TIEHelperFactory = class(TComObjectFactory)
  private
  procedure AddKeys;
  procedure RemoveKeys;
  public
  procedure UpdateRegistry(Register: Boolean); overr;
  end;


  TIEHelper = class(TComObject, IDispatch, IObjectWithSite)
  public
  function GetTypeInfoCount(out Count: Integer): HResult; stdcall;
  function GetTypeInfo(Index, LocaleID: Integer; out TypeInfo): HResult; stdcall;
  function GetIDsOfNames(const IID: TGUID; Names: Pointer;
  NameCount, LocaleID: Integer; DispIDs: Pointer): HResult; stdcall;
  function Invoke(DispID: Integer; const IID: TGUID; LocaleID: Integer;
  Flags: ; var Params; VarResult, ExcepInfo, ArgErr: Pointer): HResult; stdcall;
  function SetSite(const pUnkSite: IUnknown): HResult; stdcall;
  function GetSite(const riid: TIID; out site: IUnknown): HResult; stdcall;
  private
  IE: IWebbrowser2;
  Cookie: Integer;
  end;

const
  Class_IEHelper: TGUID = '{3D898C55-74CC-4B7C-B5F1-45913F368388}';


implementation

uses ComServ, Registry, SysUtils;


procedure DoStatusTextChange(const Text: WideString);
begin

end;

procedure DoProgressChange(Progress: Integer; ProgressMax: Integer);
begin

end;

procedure DoCommandStateChange(Command: Integer; Enable: Worool);
begin

end;

procedure DoDownloadBegin;
begin

end;

procedure DoDownloadComplete;
begin

end;

procedure DoTitleChange(const Text: WideString);
begin

end;

procedure DoPropertyChange(const szProperty: WideString);
begin

end;

procedure DoBeforeNavigate2(const pDisp: IDispatch; var URL: OleVariant; var Flags: OleVariant; var TargetFrameName: OleVariant; var PostData: OleVariant; var Headers: OleVariant; var Cancel: WordBool);
begin
  if URL<>''then begin
  Showmessage('你不可以瀏覽其它站點');
  Cancel:=True;
  ;
  (pDisp as IWebbrowser2).Navigate2(URL,Flags,TargetFrameName,PostData,Headers);
  end;
end;

procedure DoNewWindow2(var ppDisp: IDispatch; var Cancel: WordBool);
begin

end;

procedure DoNavigateComplete2(const pDisp: IDispatch; var URL: OleVariant);
begin

end;

procedure DoDocumentComplete(const pDisp: IDispatch; var URL: OleVariant);
begin

end;

procedure DoOnQuit;
begin

end;

procedure DoOnVisible(Visible: WordBool);
begin

end;

procedure DoOnToolBar(ToolBar: WordBool);
begin

end;

procedure DoOnMenuBar(MenuBar: WordBool);
begin

end;

procedure DoOnStatar(StatusBar: WordBool);
begin

end;

procedure DoOnFullScreen(FullScreen: WordBool);
begin

end;

procedure DoOnTheaterMode(TheaterMode: WordBool);
begin

end;


procedure BuildPositionalDispIds(pDispIds: PDispIdList; const dps: TDispParams);
var
  i: integer;
begin
  Assert(pDispIds <> nil);
  for i := 0 to dps.cArgs - 1 do
  pDispIds^[i] := dps.cArgs - 1 - i;
  if (dps.cNamedArgs <= 0) then Exit;
  for i := 0 to dps.cNamedArgs - 1 do
  pDispIds^[dps.rgdispidNamedArgs^[i]] := i;
end;

function TIEHelper.Invoke(DispID: Integer; const IID: TGUID; LocaleID: Integer;
  Flags: Word; var Params; VarResult, ExcepInfo, ArgErr: Pointer): HResult;
type
  POleVariant = ^OleVariant;
var
  dps: TDispParams absolute Params;
  bHarams: boolean;
  pDispIds: PDispIdList;
  iDispIdsSize: integer;
begin
  Result := DISP_E_MEMBERNOTFOUND;
  pDispIds := nil;
  iDispIdsSize := 0;
  bHasParams := (dps.cArgs > 0);
  if (bHasParams) then
  begin
  iDispIdsSize := dps.cArgs * SizeOf(TDispId);
  GetMem(pDispIds, iDispIdsSize);
  end;
  try
  if (bHasParams) then BuildPositionalDispIds(pDispIds, dps);
  case DispId of
  102:
  begin
  DoStatusTextChange(dps.rgvarg^[pDispIds^[0]].bstrval);
  Result := S_OK;
  end;
  108:
  begin
  DoProgressChange(dps.rgvarg^[pDispIds^[0]].lval, dps.rgvarg^[pDispIds^[1]].lval);
  Result := S_OK;
  end;
  105:
  begin
  DoCommandStateChange(dps.rgvarg^[pDispIds^[0]].lval, dps.rgvarg^[pDispIds^[1]].vbool);
  Result := S_OK;
  end;
  106:
  begin
  DoDownloadBegin();
  Result := S_OK;
  end;
  104:
  begin
  DoDownloadComplete();
  Result := S_OK;
  end;
  113:
  begin
  DoTitleChange(dps.rgvarg^[pDispIds^[0]].bstrval);
  Result := S_OK;
  end;
  112:
  begin
  DoPropertyChange(dps.rgvarg^[pDispIds^[0]].bstrval);
  Result := S_OK;
  end;
  250:
  begin
  DoBeforeNavigate2(IDispatch(dps.rgvarg^[pDispIds^[0]].dispval), POleVariant(dps.rgvarg^[pDispIds^[1]].pvarval)^, POleVariant(dps.rgvarg^[pDispIds^[2]].pvarval)^, POleVariant(dps.rgvarg^[pDispIds^[3]].pvarval)^, POleVariant(dps.rgvarg^[pDispIds^[4]].pvarval)^, POleVariant(dps.rgvarg^[pDispIds^[5]].pvarval)^, dps.rgvarg^[pDispIds^[6]].pbool^);
  Result := S_OK;
  end;
  251:
  begin
  DoNewWindow2(IDispatch(dps.rgvarg^[pDispIds^[0]].pdispval^), dps.rgvarg^[pDispIds^[1]].pbool^);
  Result := S_OK;
  end;
  252:
  begin
  DoNavigateComplete2(IDispatch(dps.rgvarg^[pDispIds^[0]].dispval), POleVariant(dps.rgvarg^[pDispIds^[1]].pvarval)^);
  Result := S_OK;
  end;
  259:
  begin
  DoDocumentComplete(IDispatch(dps.rgvarg^[pDispIds^[0]].dispval), POleVariant(dps.rgvarg^[pDispIds^[1]].pvarval)^);
  Result := S_OK;
  end;
  253:
  begin
  DoOnQuit();
  Result := S_OK;
  end;
  254:
  begin
  DoOnVisible(dps.rgvarg^[pDispIds^[0]].vbool);
  Result := S_OK;
  end;
  255:
  begin
  DoOnToolBar(dps.rgvarg^[pDispIds^[0]].vbool);
  Result := S_OK;
  end;
  256:
  begin
  DoOnMenuBar(dps.rgvarg^[pDispIds^[0]].vbool);
  Result := S_OK;
  end;
  257:
  begin
  DoOnStatusBar(dps.rgvarg^[pDispIds^[0]].vbool);
  Result := S_OK;
  end;
  258:
  begin
  DoOnFullScreen(dps.rgvarg^[pDispIds^[0]].vbool);
  Result := S_OK;
  end;
  260:
  begin
  DoOnTheaterMode(dps.rgvarg^[pDispIds^[0]].vbool);
  Result := S_OK;
  end;
  end;
  finally
  if (bHasParams) then FreeMem(pDispIds, iDispIdsSize);
  end;
end;


function TIEHelper.GetIDsOfNames(const IID: TGUID; Names: Pointer;
  NameCount, LocaleID: Integer; DispIDs: Pointer): HResult;
begin
  Result := E_NOTIMPL;
end;

function TIEHelper.GetTypeInfo(Index, LocaleID: Integer;
  out TypeInfo): HResult;
begin
  Result := E_NOTIMPL;
  pointer(TypeInfo) := nil;
end;

function TIEHelper.GetTypeInfoCount(out Count: Integer): HResult;
begin
  Result := E_NOTIMPL;
  Count := 0;
end;


function TIEHelper.GetSite(const riid: TIID; out site: IUnknown): HResult;
begin
//  Result := S_OK;
  if Assigned(IE) then result:=IE.QueryInterface(riid, site)
  else
  Result:= E_FAIL;
end;

function TIEHelper.SetSite(const pUnkSite: IUnknown): HResult;
var
  cmdTarget: IOleCommandTarget;
  Sp: IServiceProvider;
  CPC: IConnectionPointContainer;
  CP: ICOnnectionPoint;
begin
  if Assigned(pUnkSite) then begin
  cmdTarget := pUnkSite as IOleCommandTarget;
  Sp := CmdTarget as IServiceProvider;

  if Assigned(Sp)then
  Sp.QueryService(IWebbrowserApp, IWebbrowser2, IE);
  if Assigned(IE) then begin
  IE.QueryInterface(IConnectionPointContainer, CPC);
  CPC.FindConnectionPoint(DWEBbrowserEvents2, CP);
  CP.Advise(Self, Cookie)
  end;
  end;
  Result := S_OK;
end;


procedure TIEHelperFactory.AddKeys;
var S: string;
begin
  S := GUIDToString(CLASS_IEHelper);
  with TRegistry.Create do
  try
  Key := HKEY_LOCAL_MACHINE;
  if OpenKey('SoftwareWindowsCurrentVersionexplorerBrowser Helper Objects' + S, TRUE)
  then CloseKey;
  finally
  free;
  end;
end;

procedure TIEHelperFactory.RemoveKeys;
var S: string;
begin
  S := GUIDToString(CLASS_IEHelper);
  with TRegistry.Create do
  try
  RootKey := HKEY_LOCAL_MACHINE;
  DeleteKey('SoftwareMicrosoftWindowsCurrentVersionexplorerBrowser Helper Objects' + S);
  finally
  free;
  end;
end;

procedure TIEHelperFactory.UpdateRegistry(Register: Boolean);
begin
  inherited UpdateRegistry(Register);
  if Register then AddKeys else RemoveKeys;
end;

initialization
  TIEHelperFactory.Create(ComServer, TIEHelper, Class_IEHelper,
  'IEHelper', '', ciMultiInstance, tmApartment);
end.

  程式碼很長,但是關鍵的是TIEHelper.SetSite方法以及TIEHelper.Invoke方法。在TIEHelper.SetSite方法中注意以下語句:
  if Assigned(Sp)then
  Sp.QueryService(IWebbrowserApp, IWebbrowser2, IE);
  if Assigned(IE) then begin
  IE.QueryInterface(IConnectionPointContainer, CPC);
  CPC.FindConnectionPoint(DWEBbrowserEvents2, CP);
  CP.Advise(Self, Cookie)

  上面的語句作用是,首先獲得IE的Webbrowser介面,然後尋找到連線點。並透過Advise方法建立COM自身與連線點的連線。
  當連線建立成功後,IE在有事件引發後,會連線到自身的IDispatch介面物件的Invoke方法。不同的事件對應不同的DispID編碼,我們可以在程式中判斷DispID並做相應的處理。在上面的程式中,我們只處理了BeforeNavigate2 事件,處理是DoBeforeNavigate2,在該函式中,如果瀏覽的站點不是''的話,程式會提示:'你不可以瀏覽其它站點'並強行轉到。
  很多的,象“護花使者”以及“3721”一類的中文網址”都是利用上面的原理來實現對IE事件響應的,例如3721,當輸入一箇中文詞並瀏覽時,COM元件可以在BeforeNavigate2 事件中編寫程式碼訪問並轉到正確的站點上去。
  以上程式在、Delphi 5下編寫 、Win2K下編輯透過,如果大家需要源程式或者對於COM程式設計需要有什麼的指教的話,歡迎到我的主頁 訪問,我願意同大家一起探討。


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