WebBrowser组件和MSHTML 在Delphi中的使用

MSHTML把HTML页面中的元素封装成了IHTMLInputElement、 IHTMLInputButtonElement、IHTMLInputTextElement、IHTMLTextAreaElement、IHTMLTitleElement、IHTMLFormElement等等组件接口。
在程序中可以通过MSHTML提供的IHTMLDocument2接口得到整个Document对象，IHTMLElementCollection接口得到所有页面元素的集合,通过该接口的Item方法可以得到具体的某个组件,然后设置和读取该组件的属性值。
下面是一些常用功能的事例代码.
1． 打开某个页面：
web.Navigate(ExtractFilePath(Application.ExeName) + 'Template/login.html');
2． 取出页面中某个HtmlElement的Value属性值：
function GetValueByElementName(web: TWebBrowser; elementName: string; index: integer): string;
begin
result := (((web.Document as IHTMLDocument2).body.all as
IHTMLElementCollection).item(elementName, index) as IHTMLInputElement
).value
end;
3． 给HtmlElement设置Value属性
procedure SetValueTextAreaName(web: TWebBrowser; elementName, value: string;index: integer);
begin
(((web.Document as IHTMLDocument2).body.all as
IHTMLElementCollection).item(elementName, index) as IHTMLTextAreaElement
).value := value;
end;
4． 判断页面执行结果是否成功
因为Web应用中如果出错的一般是采用错误页面的方式呈现给最终用户,所以我们也无法抓到Http错误,只能通过在webBeforeNavigate2事件中将URL参数记录到全局变量中, 然后在webDocumentComplete事件中根据URL参数和全局变量中的URL参数来判断执行结果是否正确.当然,这样需要将页面地址编码到代码中,降低了灵活性,但是这也是我能想到的唯一的方法,如果大家有什么好的方法,请告诉我哦.
5． 屏蔽鼠标右键和某些快捷键
本功能需要在webBrowser的窗口中加入ApplicationEvents组件,设置它的OnMessage事件代码如下即可.
procedure TwebAdapterForm.ApplicationEvents1Message(var Msg: tagMSG;
var Handled: Boolean);
const
_KeyPressMask = $80000000;
begin
//禁用右键
with Msg do
begin
if not IsChild(web.Handle, hWnd) then Exit;
Handled := (message = WM_RBUTTONDOWN) or (message = WM_RBUTTONUP) or (message = WM_CONTEXTMENU);
end;
//禁止Ctrl + N
//禁止Ctrl + F
//禁止Ctrl + A
if Msg.message = WM_KEYDOWN then
begin
if ((Msg.lParam and _KeyPressMask) = 0) and
(GetKeyState(VK_Control) <0) and ((Msg.wParam = Ord('N'))
or (Msg.wParam = Ord('F')) or (Msg.wParam = Ord('A'))) then
begin
Handled := True;
end;
end;
end;
6． 在页面关闭的时候,同时关掉包含页面的VCL Form.(仅限 InternetExplorer 6.0)
本功能需要卸载掉Delphi自带的 WebBrowser组件,安装ActionX组件(Microsoft Internet Controls V1.1),而且以后的程序只能运行在安装有Internet Explorer 6.0 的环境下.具体方法如下:
在WebBrowser组件的OnWindowClosing事件中,输入self.close; 代码即可.如果需要阻止窗口的关闭, 设置CanClose参数的值为Flase.
7． 如何将页面中超链接新开的页面窗口包到指定的VCL窗口中.
procedure TForm1.webNewWindow2(Sender: TObject; var ppDisp: IDispatch;
var Cancel: WordBool);
var
form : TForm1;
begin
form := TForm1.Create(nil);
ppDisp := form.web.DefaultDispatch;
form.Show;
end;
8． 在WebBrowser加载html页面完成后,在页面顶端插入HTML代码, 下面两种方式斗可以.
{1. ----------------------------------------------------------------}
procedure TForm1.Button1Click(Sender: TObject);
var
Range: IHTMLTxtRange;
begin
Range := ((WebBrowser1.Document as IHTMLDocument2).body as
IHTMLBodyElement).createTextRange;
Range.collapse(False);
Range.pasteHTML('<br/><b>Hello!</b>');
end;
{2. ----------------------------------------------------------------}
procedure TForm1.WebBrowser1DocumentComplete(Sender: TObject;
const pDisp: IDispatch; var URL: OleVariant);
var
WebDoc: HTMLDocument;
WebBody: HTMLBody;
begin
WebDoc := WebBrowser1.Document as HTMLDocument;
WebBody := WebDoc.body as HTMLBody;
WebBody.insertAdjacentHTML('BeforeEnd', '<h1>Hello World!</h1>');
end;
9． 将页面中显示的内容全部选中,然后粘贴到Word文档中.
WebBrowser1.ExecWB(OLECMDID_SELECTALL, OLECMDEXECOPT_DODEFAULT);//全选网页
WebBrowser1.ExecWB(OLECMDID_COPY, OLECMDEXECOPT_DODEFAULT); //复制网页
WordDocu.Range.Paste; //word文档粘贴
WebBrowser1.ExecWB(OLECMDID_UNDO, OLECMDEXECOPT_DODEFAULT); //取消全选
注:WebBrowser的Document属性值和WordDocument的Document属性值必须都不为nil.
10． 如何解决网页不响应回车事件
public
{ Public declarations }
procedure MsgHandle(var Msg :TMsg; var Handled :Boolean);
end;
var
Form1: TForm1;
FOleInPlaceActiveObject :IOleInPlaceActiveObject;
implementation
{$R *.DFM}
procedure TForm1.MsgHandle(var Msg :TMsg; var Handled :Boolean);
var
iOIPAO :IOleInPlaceActiveObject;
Dispatch :IDispatch;
begin
if WebBrowser1 =nil then
begin
Handled :=False;
Exit;
end;
Handled :=(IsDialogMessage(WebBrowser1.Handle, Msg) =True);
if (Handled) and (not WebBrowser1.Busy) then
begin
if FOleInPlaceActiveObject =nil then
begin
Dispatch :=WebBrowser1.Application;
if Dispatch <>nil then
begin
Dispatch.QueryInterface(IOleInPlaceActiveObject, iOIPAO);
if iOIPAO <>nil then
FOleInPlaceActiveObject :=iOIPAO;
end;
end;
end;
if FOleInPlaceActiveObject <>nil then
if ((Msg.message =WM_KEYDOWN) or (Msg.Message =WM_KEYUP)) and ((Msg.wParam =VK_BACK) or (Msg.wParam =VK_LEFT) or (Msg.wParam =VK_RIGHT)) then
else
FOleInPlaceActiveObject.TranslateAccelerator(Msg);
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
Application.OnMessage :=MsgHandle;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
FOleInPlaceActiveObject :=nil;
end;
11． 如何在WebBrowser中调用当前页面中的javascript函数SayHello()
WebBrowser1.OleObject.
Document.parentWindow.execScript('SayHello()', 'javascript');
//or
(WebBrowser1.Document as IHTMLDocument2
).parentWindow.execScript('SayHello()', 'javascript')
//or
webrowser1.document.script.SayHello();