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Implementing IDispatch for Webbrowser.....

How would I implement the IDispatch interface to handle the following in
VB.Net

<BEGIN>
Controlling Download and Execution
The WebBrowser Control gives you control over what it downloads, displays,
and executes. To gain this control, you need to implement your host's
IDispatch so it handles DISPID_AMBIENT_ DLCONTROL. When the WebBrowser
Control is instantiated, it will call your IDispatch::Invo ke with this ID.
Set pvarResult to a combination of following flags, using the bitwise OR
operator, to indicate your preferences.

a.. DLCTL_DLIMAGES, DLCTL_VIDEOS, and DLCTL_BGSOUNDS: Images, videos, and
background sounds will be downloaded from the server and displayed or played
if these flags are set. They will not be downloaded and displayed if the
flags are not set.
b.. DLCTL_NO_SCRIPT S and DLCTL_NO_JAVA: Scripts and Java applets will not
be executed.
c.. DLCTL_NO_DLACTI VEXCTLS and DLCTL_NO_RUNACT IVEXCTLS : ActiveX controls
will not be downloaded or will not be executed.
d.. DLCTL_DOWNLOADO NLY: The page will only be downloaded, not displayed.
e.. DLCTL_NO_FRAMED OWNLOAD: The WebBrowser Control will download and parse
a frameSet, but not the individual frame objects within the frameSet.
f.. DLCTL_RESYNCHRO NIZE and DLCTL_PRAGMA_NO _CACHE: These flags cause cache
refreshes. With DLCTL_RESYNCHRO NIZE, the server will be asked for update
status. Cached files will be used if the server indicates that the cached
information is up-to-date. With DLCTL_PRAGMA_NO _CACHE, files will be
re-downloaded from the server regardless of the update status of the files.
g.. DLCTL_NO_BEHAVI ORS: Behaviors are not downloaded and are disabled in
the document.
h.. DLCTL_NO_METACH ARSET_HTML: Character sets specified in meta elements
are suppressed.
i.. DLCTL_URL_ENCOD ING_DISABLE_UTF 8 and DLCTL_URL_ENCOD ING_ENABLE_UTF8 :
These flags function similarly to the
DOCHOSTUIFLAG_U RL_ENCODING_DIS ABLE_UTF8 and
DOCHOSTUIFLAG_U RL_ENCODING_ENA BLE_UTF8 flags used with
IDocHostUIHandl er::GetHostInfo . The difference is that the DOCHOSTUIFLAG
flags are checked only when the WebBrowser Control is first instantiated.
The download flags here for the ambient property change are checked whenever
the WebBrowser Control needs to perform a download.
j.. DLCTL_NO_CLIENT PULL: No client pull operations will be performed.
k.. DLCTL_SILENT: No user interface will be displayed during downloads.
l.. DLCTL_FORCEOFFL INE: The WebBrowser Control always operates in offline
mode.
m.. DLCTL_OFFLINEIF NOTCONNECTED and DLCTL_OFFLINE: These flags are the
same. The WebBrowser Control will operate in offline mode if not connected
to the Internet.
DISPID_AMBIENT_ DLCONTROL and the flag values are defined in mshtmdid.h.

Initially, when the function call to IDispatch::Invo ke starts, the VARIANT
to which the parameter pvarResult points is of type VT_EMPTY. You must
switch the type to VT_I4 for any settings to have an effect. You can place
your flag values in the lVal member of the VARIANT.

Most of the flag values have negative effects, that is, they prevent
behavior that normally happens. For instance, scripts are normally executed
by the WebBrowser Control if you don't customize its behavior. But if you
set the DLCTL_NOSCRIPTS flag, no scripts will execute in that instance of
the control. However, three flags-DLCTL_DLIMAGES, DLCTL_VIDEOS, and
DLCTL_BGSOUNDS-work exactly opposite. If you set flags at all, you must set
these three for the WebBrowser Control to behave in its default manner
vis-a-vis images, videos and sounds.

The following code sample causes a WebBrowser Control instance to download
and display images and videos, but not background sounds, since the
DLCTL_BGSOUNDS is not explicitly set. Also, script execution on pages
displayed by the WebBrowser Control is disabled.

STDMETHODIMP CAtlBrCon::Invo ke(DISPID dispidMember, REFIID riid,
LCID lcid, WORD wFlags,
DISPPARAMS* pDispParams,
VARIANT* pvarResult,
EXCEPINFO* pExcepInfo,
UINT* puArgErr)
{
switch (dispidMember)
{
case DISPID_AMBIENT_ DLCONTROL:
pvarResult->vt = VT_I4;
pvarResult->lVal = DLCTL_DLIMAGES | DLCTL_VIDEOS | DLCTL_NO_SCRIPT S;
break;

default:
return DISP_E_MEMBERNO TFOUND;
}

return S_OK;
}
<END>Thanks so much for your help. Contributors will be listed in the
freeware browser being developed.
Nov 21 '05 #1
0 3469

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