Cynna封装的TDHTMLEvent类（TWebBrowser常用）

Delphi中一些比较常用的方法和函数

PageControl封装WebBrowser及游览器 ?

2010-8

4

Cynna封装的TDHTMLEvent类（TWebBrowser常用）

发表于: Delphi | 作者: 代码哥哥

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// ************* TDHTMLEvent class is placed in this separate unit ******************// 1. File -> New -> Unit// 2. Copy/Paste this code: unit Unit2; interface uses Windows, Classes; type TDHTMLEvent = class (TObject, IUnknown, IDispatch) private FRefCount: Integer; FOldEvent: IDispatch; FElementEvent: TNotifyEvent; // IUnknown function QueryInterface(const IID: TGUID; out Obj): Integer; stdcall; function _AddRef: Integer; stdcall; function _Release: Integer; stdcall; // IDispatch 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: Word; var Params; VarResult, ExcepInfo, ArgErr: Pointer): HResult; stdcall; public { Public declarations } function HookEventHandler(CallerHandler: TNotifyEvent): IDispatch; property ElementEvent: TNotifyEvent read FElementEvent write FElementEvent; end; implementation { TDHTMLEvent }  function TDHTMLEvent._AddRef: Integer;begin Inc(FRefCount); Result := FRefCount;end; function TDHTMLEvent._Release: Integer;begin Dec(FRefCount); Result := FRefCount;end; function TDHTMLEvent.GetIDsOfNames(const IID: TGUID; Names: Pointer; NameCount, LocaleID: Integer; DispIDs: Pointer): HResult;begin if FOldEvent <> nil then Result := FOldEvent.GetIDsOfNames(IID, Names, NameCount, LocaleID, DispIDs) else Result := E_NOTIMPL;end; function TDHTMLEvent.GetTypeInfo(Index, LocaleID: Integer; out TypeInfo): HResult;begin if FOldEvent <> nil then Result := FOldEvent.GetTypeInfo(Index, LocaleID, TypeInfo) else begin Pointer(TypeInfo) := nil; Result := E_NOTIMPL; endend; function TDHTMLEvent.GetTypeInfoCount(out Count: Integer): HResult;begin if FOldEvent <> nil then Result := FOldEvent.GetTypeInfoCount(Count) else begin Count := 0; Result := S_OK; end;end; function TDHTMLEvent.QueryInterface(const IID: TGUID; out Obj): Integer;begin if GetInterface(IID, Obj) then Result := S_OK else Result := E_NOINTERFACE;end; function TDHTMLEvent.Invoke(DispID: Integer; const IID: TGUID; LocaleID: Integer; Flags: Word; var Params; VarResult, ExcepInfo, ArgErr: Pointer): HResult;begin try if Assigned(FElementEvent) then FElementEvent(Self); finally if FOldEvent <> nil then Result := FOldEvent.Invoke(DispID, IID, LocaleID, Flags, Params, VarResult, ExcepInfo, ArgErr) else Result := E_NOTIMPL; end;end; function TDHTMLEvent.HookEventHandler(CallerHandler: TNotifyEvent): IDispatch;begin FOldEvent:=nil; ElementEvent:=CallerHandler; Result:=Self;end;  end.    //********************* DEMO *************************// Principles from your last question are kept. This code is variation// of existing code, modified to accomodate use of events. uses Unit2; // Contains TDHTMLEvent // .... var Form1: TForm1; InputKeyPress: TDHTMLEvent; // .... procedure TForm1.FormCreate(Sender: TObject);begin InputKeyPress:=TDHTMLEvent.Create;end; procedure SetOnChangeInputElement(Browser:TWebBrowser; ElementName: String; EventObject: TDHTMLEvent; EventHandler:TNotifyEvent);var WebDoc : IHTMLDocument2; pDispatch : IDISPATCH; elements : IHTMLElementCollection; Input : IHTMLInputElement;begin OleCheck(Browser.Document.QueryInterface(IID_IHTMLDocument2, WebDoc)); // grab all elements: elements := WebDoc.Get_all; // find first with the name ElementName: pDispatch := elements.item(ElementName, 0); // get it: OleCheck(pDispatch.QueryInterface(IID_IHTMLInputElement, Input)); // now you can hook event handler to our object: OleVariant(Input).OnKeyDown:=EventObject.HookEventHandler(EventHandler);end; procedure TForm1.DHTMLElementEvent(Sender: TObject);begin // This is triggered with each KeyDown event Panel1.Color:=RGB(Random(254), Random(254), Random(254));end; // DEMO:// -------- procedure TForm1.Button1Click(Sender: TObject);var site: String;begin // Surf to EE: site:='http://www.experts-exchange.com/Programming/Programming_Languages/Delphi/Q_20339253.html'; WebBrowser1.Navigate(site); // Wait for page to fully load: while WebBrowser1.ReadyState<>READYSTATE_COMPLETE do begin Sleep(1); Application.ProcessMessages; end; // Hook it: SetOnChangeInputElement (WebBrowser1, 'keyWord', // We are hooking event in INPUT field named "keyWord" InputKeyPress, // TDHTMLEvent object dedicated to this event DHTMLElementEvent // Our own event handler that will get hooked by InputKeyPress );end;   Run it, and then type something in Search box. Panel1 will change color with each key press.

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