利用DELPHI编写IE扩展
116、利用DELPHI编写IE扩展
在自己的程序中使用过WebBrowser控件的朋友都知道,WebBrowser控件定义了诸如BeforeNavigate、DownloadComplete 等事件,我们可以通过编写事件处理代码实现对WebBrowser控件的操作。那么如何实现对IE的事件响应和处理呢?同建立IE面板一样。我们需要建立一个实现IObjectWithSite接口的COM组件,不同的是,我们还需要实现IDispatch接口,在IObjectWithSite接口的SetSite方法中获得IE的WebBrowser接口并建立自身与WebBrowser的连接,然后如果在IE的Webbrowser对象中发生什么事件的话,那么IE就会回调连接的IDispatch接口的Invoke方法。我们通过在Invoke方法中编写代码就可以获得IE事件了。这个利用的是COM编程的回调接口原理。
下面我们首先来实现代码。点击Delphi菜单 File | New 。在 ActiveX 页面中选择Active Library ,然后点击 OK 按钮。然后用同样的方法建立一个COM Object。在COM Object Wizard 窗口中,将复选框 Included type library 去掉。然后在Class Name中输入IEHelper,在Implemented Interface 中输入:IDispatch;IObjectwithSite 。然后点击 OK 按钮建立一个COM组件。
保存工程,将工程保存为IEHelper.dpr,将Unit1保存为IEHelperUnit.pas。下面是IEHelperUnit.pas的具体代码:
unit iehelperunit
interface
uses
WIndows, Comobj, ActiveX, SHDOCVW, MSHTML,Dialogs
type
TIEHelperFactory = class(TComObjectFactory)
private
procedure AddKeys
procedure RemoveKeys
public
procedure UpdateRegistry(Register: Boolean)
override
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(c onst IID: TGUID
Names: Pointer
NameCount, LocaleID: Integer
DispIDs: Pointer): HResult
stdcall
function Invoke(DispID: Integer
c onst IID: TGUID
LocaleID: Integer
Flags: Word
var Params
VarResult, ExcepInfo, ArgErr: Pointer): HResult
stdcall
function SetSite(c onst pUnkSite: IUnknown): HResult
stdcall
function GetSite(c onst riid: TIID
out site: IUnknown): HResult
stdcall
private
IE: IWebbrowser2
Cookie: Integer
end
c onst
Class_IEHelper: TGUID = '{3D898C55-74CC-4B7C-B5F1-45913F368388}'
implementation
uses ComServ, Registry, SysUtils
procedure DoStatusTextChange(c onst Text: WideString)
begin
end
procedure DoProgressChange(Progress: Integer
ProgressMax: Integer)
begin
end
procedure DoCommandStateChange(Command: Integer
Enable: WordBool)
begin
end
procedure DoDownloadBegin
begin
end
procedure DoDownloadComplete
begin
end
procedure DoTitleChange(c onst Text: WideString)
begin
end
procedure DoPropertyChange(c onst szProperty: WideString)
begin
end
procedure DoBeforeNavigate2(c onst pDisp: IDispatch
var URL: OleVariant
var Flags: OleVariant
var TargetFrameName: OleVariant
var PostData: OleVariant
var Headers: OleVariant
var Cancel: WordBool)
begin
if URL<>'http://www.applevb.com/&#39;then begin
Showmessage('你不可以浏览其它站点')
Cancel:=True
URL:='http://www.applevb.com&#39;
(pDisp as IWebbrowser2).Navigate2(URL,Flags,TargetFrameName,PostData,Headers)
end
end
procedure DoNewWindow2(var ppDisp: IDispatch
var Cancel: WordBool)
begin
end
procedure DoNavigateComplete2(c onst pDisp: IDispatch
var URL: OleVariant)
begin
end
procedure DoDocumentComplete(c onst 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 DoOnStatusBar(StatusBar: WordBool)
begin
end
procedure DoOnFullScreen(FullScreen: WordBool)
begin
end
procedure DoOnTheaterMode(TheaterMode: WordBool)
begin
end
procedure BuildPositionalDispIds(pDispIds: PDispIdList
c onst dps: TDispParams)
var
i: integer
begin
Assert(pDispIds <> nil)
for i := 0 to dps.cArgs - 1 do
pDispIds^ := 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
c onst IID: TGUID
LocaleID: Integer
Flags: Word
var Params
VarResult, ExcepInfo, ArgErr: Pointer): HResult
type
POleVariant = ^OleVariant
var
dps: TDispParams absolute Params
bHasParams: 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(c onst 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(c onst 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(c onst pUnkSite: IUnknown): HResult
var
cmdTarget: IOleCommandTarget
Sp: IServiceProvider
CPC: Ic onnectionPointc ontainer
CP: Ic onnectionPoint
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(Ic onnectionPointc ontainer, CPC)
CPC.Findc onnectionPoint(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
RootKey := HKEY_LOCAL_MACHINE
if OpenKey('Software/Microsoft/Windows/CurrentVersion/explorer/Browser 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('Software/Microsoft/Windows/CurrentVersion/explorer/Browser 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.
代码很长,但是关键的是TIEHelper.SetSite方法以及TIEHelper.Invoke方法。在TIEHelper.SetSite方法中注意以下语句:
if Assigned(Sp)then
Sp.QueryService(IWebbrowserApp, IWebbrowser2, IE)
if Assigned(IE) then begin
IE.QueryInterface(Ic onnectionPointc ontainer, CPC)
CPC.Findc onnectionPoint(DWEBbrowserEvents2, CP)
CP.Advise(Self, Cookie)
上面的语句作用是,首先获得IE的Webbrowser接口,然后寻找到连接点。并通过Advise方法建立COM自身与连接点的连接。
当连接建立成功后,IE在有事件引发后,会调用连接到自身的IDispatch接口对象的Invoke方法。不同的事件对应不同的DispID编码,我们可以在程序中判断DispID并做相应的处理。在上面的程序中,我们只处理了BeforeNavigate2 事件,处理函数是DoBeforeNavigate2,在该函数中,如果浏览的站点不是'http://www.applevb.com/&#39;的话,程序会提示:'你不可以浏览其它站点'并强行转到http://www.applevb.com。
很多的软件,象“护花使者”以及“3721”一类的中文网址”都是利用上面的原理来实现对IE浏览器事件响应的,例如3721,当用户输入一个中文词并浏览时,COM组件可以在BeforeNavigate2 事件中编写代码访问服务器并转到正确的站点上去。