我有一个显示Google地图页面的TWebBrowser组件。问题是,当用户按F5页面刷新和页面重新加载。这会导致javascript变量重新初始化并与Delphi不同步,并出现脚本错误对话框, 'undefined'为null或不是对象。
我想停止用户刷新。
我为OnBeforeNavigate2尝试了这个事件:
procedure TNewOrganizationForm.mapAddressBeforeNavigate2(ASender: TObject;
const pDisp: IDispatch; var URL, Flags, TargetFrameName, PostData,
Headers: OleVariant; var Cancel: WordBool);
begin
inherited;
Cancel := Assigned(fMapEngine) and not fMapEngine.Loading;
end;
但是当我设置一个断点时,它甚至都没有被调用。还有另一种方式吗?
答案 0 :(得分:8)
Ronald你可以使用IHTMLDocument2.onkeydown事件拦截并阻止一个密钥。
首先分配事件处理程序,必须使用IHTMLEventObj
作为参数创建过程类型。
THTMLProcEvent = procedure(Sender: TObject; Event: IHTMLEventObj) of object;
然后你必须从InterfacedObject
和IDispatch
创建一个后代类来传递和处理事件。
最后你可以用这种方式处理onkeydown事件中的截获密钥
Var
HTMLDocument2 : IHTMLDocument2;
begin
if Not Assigned(WebBrowser1.Document) then Exit;
HTMLDocument2:=(WebBrowser1.Document AS IHTMLDocument2);
if HTMLDocument2.parentWindow.event.keyCode=VK_F5 then //compare the key
begin
HTMLDocument2.parentWindow.event.cancelBubble:=True; //cancel the key
HTMLDocument2.parentWindow.event.keyCode :=0;
end;
end;
//检查完整的源代码
unit Unit55;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, OleCtrls, SHDocVw, MSHTML;
type
//Create the procedure type to assign the event
THTMLProcEvent = procedure(Sender: TObject; Event: IHTMLEventObj) of object;
//Create a new class for manage the event from the twebbrowser
THTMLEventLink = class(TInterfacedObject, IDispatch)
private
FOnEvent: THTMLProcEvent;
private
constructor Create(Handler: THTMLProcEvent);
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
property OnEvent: THTMLProcEvent read FOnEvent write FOnEvent;
end;
TForm55 = class(TForm)
WebBrowser1: TWebBrowser;
procedure FormShow(Sender: TObject);
procedure WebBrowser1NavigateComplete2(ASender: TObject; const pDisp: IDispatch; var URL: OleVariant);
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
FOnKeyDownConnector: THTMLEventLink; //pointer to the event handler
procedure WebBrowser1OnKeyDown(Sender: TObject; EventObjIfc: IHTMLEventObj);//the event handler
public
{ Public declarations }
end;
var
Form55: TForm55;
implementation
{$R *.dfm}
constructor THTMLEventLink.Create(Handler: THTMLProcEvent);
begin
inherited Create;
_AddRef;
FOnEvent := Handler;
end;
function THTMLEventLink.GetIDsOfNames(const IID: TGUID; Names: Pointer; NameCount, LocaleID: Integer; DispIDs: Pointer): HResult;
begin
Result := E_NOTIMPL;
end;
function THTMLEventLink.GetTypeInfo(Index, LocaleID: Integer; out TypeInfo): HResult;
begin
Result := E_NOTIMPL;
end;
function THTMLEventLink.GetTypeInfoCount(out Count: Integer): HResult;
begin
Result := E_NOTIMPL;
end;
function THTMLEventLink.Invoke(DispID: Integer; const IID: TGUID; LocaleID: Integer; Flags: Word; var Params; VarResult, ExcepInfo, ArgErr: Pointer): HResult;
var
HTMLEventObjIfc: IHTMLEventObj;
begin
Result := S_OK;
if Assigned(FOnEvent) then FOnEvent(Self, HTMLEventObjIfc);
end;
procedure TForm55.FormCreate(Sender: TObject);
begin
FOnKeyDownConnector := THTMLEventLink.Create(WebBrowser1OnKeyDown); //assign the address of the event handler
end;
procedure TForm55.WebBrowser1NavigateComplete2(ASender: TObject; const pDisp: IDispatch; var URL: OleVariant);
var
HTMLDocument2 : IHTMLDocument2;
begin
HTMLDocument2:=(WebBrowser1.Document AS IHTMLDocument2);
HTMLDocument2.onkeydown := FOnKeyDownConnector as IDispatch; //assign the event handler
end;
procedure TForm55.WebBrowser1OnKeyDown(Sender: TObject; EventObjIfc: IHTMLEventObj);
Var
HTMLDocument2 : IHTMLDocument2;
begin
//finally do your stuff here, in this case we will intercept and block the F5 key.
if Not Assigned(WebBrowser1.Document) then Exit;
HTMLDocument2:=(WebBrowser1.Document AS IHTMLDocument2);
if HTMLDocument2.parentWindow.event.keyCode=VK_F5 then
begin
HTMLDocument2.parentWindow.event.cancelBubble:=True;
HTMLDocument2.parentWindow.event.keyCode :=0;
end;
end;
procedure TForm55.FormShow(Sender: TObject);
begin
WebBrowser1.Navigate('www.google.com');
end;
end.
答案 1 :(得分:0)
我没有找到一个简单的方法来做到这一点。我在TWebBrowser上找不到任何类似的事件或类似内容,这会让人感到不快。也许您应该检查TEmbededWB,因为它有更多的事件,并且比默认的TWebBrowser更有能力。否则它们非常相似。
但我发现了一种防止刷新的方法。现在很有趣的是,即使KeyPreview在主窗体上设置为“True”,我也无法收到关键通知。似乎TWebBrowser以某种方式吃掉它们。但这很有效:
procedure TForm1.FormCreate(Sender: TObject);
begin
Application.OnMessage := OnAppMessage;
end;
procedure TForm1.OnAppMessage(var Msg: TMsg; var Handled: Boolean);
begin
if Msg.message = WM_KEYDOWN then
if Msg.wParam = VK_F5 then
Handled := True;
end;
不是最优雅的方式,但至少它有效。我还没有找到更好的解决方案。