URLDownloadToFile Function
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Downloads bits from the Internet and saves them to a file.
Syntax
HRESULT URLDownloadToFile( LPUNKNOWN pCaller,
LPCTSTR szURL,
LPCTSTR szFileName,
DWORD dwReserved,
LPBINDSTATUSCALLBACK lpfnCB
);
Parameters
pCaller
Pointer to the controlling IUnknown interface of the calling Microsoft
ActiveX component (if the caller is an
ActiveX component). If the calling application is not an
ActiveX component, this value can be set to NULL. Otherwise, the caller is a Component Object Model (
COM) object that is contained in another component (such as an
ActiveX control within the context of an
HTML page). This parameter represents the outermost IUnknown of the calling component. The function attempts the download within the context of the
ActiveX client framework and allows the caller's container to receive callbacks on the progress of the download.
szURL
Pointer to a string value containing the
URL to be downloaded. Cannot be set to NULL. If the
URL is invalid, INET_E_DOWNLOAD_FAILURE is returned.
szFileName
Pointer to a string value containing the name of the file to create for bits that come from the download.
dwReserved
Reserved. Must be set to 0.
lpfnCB
Pointer to the caller's IBindStatusCallback interface. URLDownloadToFile calls this interface's IBindStatusCallback::OnProgress method on a connection activity, including the arrival of data. IBindStatusCallback::OnDataAvailable is never called. Implementing IBindStatusCallback::OnProgress allows a caller to implement a user interface or other progress monitoring functionality. It also allows the download operation to be canceled by returning E_ABORT from the IBindStatusCallback::OnProgress call. This can be set to NULL.
Return Value
Returns one of the following values.
S_OK The operation succeeded.
E_OUTOFMEMORY The buffer length is invalid or there was insufficient memory to complete the operation.
INET_E_DOWNLOAD_FAILURE The download of the specified resource has failed.