Re: Automating dialog with web server from VB.NET

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From: Mark Gross (mgross_at_deq.state.id.us)
Date: 04/14/04 

Date: Wed, 14 Apr 2004 11:56:47 -0600

Peter,

Thank you very much. This will keep me busy for a while. I appreciate the
guidance.

My wife had a rough night last night with a bad reaction to the chemotherapy (ICE -
ifosomide/carboplatin/etopocide) which has to be administered over 3 days in the
hospital. Although the leukemia is terminal and swift, she is actually responding
to treatment and gaining strength. We are grateful for each day.

thank you again,
mark

Peter Huang wrote:

> Hi Mark,
>
> I am sorry to hear that.
> Hope your wife will recover soon.
>
> As for the question that retrieve the frame src, because the security
> concern, we can not use the mshtml library to access the frame's property
> directly.
> As a workaround, we have to access the WebBrowser object model of frame
> windows in an HTML page inside the control by using the IOleContainer
> interface.
>
> e.g. the html file we got from the post operation is as below.
> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN">
> <html>
> <head>
> <title>Nested Hierarchy Frameset</title>
> <meta name="GENERATOR" content="Microsoft Visual Studio .NET 7.1">
> <meta content="http://schemas.microsoft.com/intellisense/ie5"
> name="vs_targetSchema">
> </head>
> <frameset cols="150,*">
> <frame name="left" src="http://www.google.com" scrolling="no" noresize>
> <frameset rows="20%,*">
> <frame name="rtop" src="http://www.microsoft.com">
> <frame name="rbottom" src="http://www.yahoo.com">
> </frameset>
> <noframes>
> <p id="p1">
> This HTML frameset displays multiple Web pages. To view this frameset,
> use a Web browser that supports HTML 4.0 and later.
> </p>
> </noframes>
> </frameset>
> </html>
>
> Here is the VB.NET code to get the Frame URL.
> We may need to add an WebBrowser control onto the form to achieve out goal,
> but we can make the control invisible.
>
> 1. We need to declare some interface.
>
> Imports System.Runtime.InteropServices
> <ComVisible(True), Guid("0000011B-0000-0000-C000-000000000046"),
> InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)> _
> Interface IOleContainer
> Sub ParseDisplayName(<[In](), MarshalAs(UnmanagedType.Interface)> ByVal
> pbc As [Object], <[In](), MarshalAs(UnmanagedType.BStr)> ByVal
> pszDisplayName As [String], <Out(), MarshalAs(UnmanagedType.LPArray)> ByVal
> pchEaten() As Integer, <Out(), MarshalAs(UnmanagedType.LPArray)> ByVal
> ppmkOut() As [Object])
> Function EnumObjects(<[In](), MarshalAs(UnmanagedType.U4)> ByVal
> grfFlags As Integer, <Out()> ByRef ppenum As IEnumUnknown) As Integer
> Sub LockContainer(<[In](), MarshalAs(UnmanagedType.I4)> ByVal fLock As
> Integer)
> End Interface 'IOleContainer
> Public Enum tagOLECONTF
> EMBEDDINGS = 1
> LINKS = 2
> OTHERS = 4
> ONLYUSER = 8
> ONLYIFRUNNING = 16
> End Enum
> <ComImport(), InterfaceType(ComInterfaceType.InterfaceIsIUnknown),
> Guid("00000100-0000-0000-C000-000000000046")> _
> Public Interface IEnumUnknown
> <PreserveSig()> _
> Function [Next](ByVal celt As Integer,
> <MarshalAs(UnmanagedType.IUnknown)> ByRef rgelt As [Object], ByRef
> pceltFetched As Integer) As Integer
> <PreserveSig()> _
> Function Skip(ByVal celt As Integer) As Integer
> <PreserveSig()> _
> Function Reset() As Integer
> <PreserveSig()> _
> Function Clone(ByRef ppenum As IEnumUnknown) As Integer
> End Interface
>
> 2. We use the WebBrowser control to load the html file we get from the
> post operation and save to harddisk( we note it as test.html)
>
> Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Load
> Me.AxWebBrowser1.Visible = False
> Me.AxWebBrowser1.Navigate("c:\test.html")
> End Sub
>
> Private Sub AxWebBrowser1_DownloadComplete(ByVal sender As Object,
> ByVal e As System.EventArgs) Handles AxWebBrowser1.DownloadComplete
> MsgBox("Download complele")
> End Sub
>
> 3. After the the document has been downloaded, we can run the code below to
> get the urls.
>
> Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles Button2.Click
> Dim pContainer As IOleContainer '
> Dim o As IEnumUnknown
> Dim pEnumerator As IEnumUnknown
> Dim pUnk As Object
> Dim pBrowser As SHDocVw.IWebBrowser2
> pContainer = CType(Me.AxWebBrowser1.Document, IOleContainer)
> ' Get an enumerator for the frames
> If pContainer.EnumObjects(tagOLECONTF.EMBEDDINGS, pEnumerator) = 0
> Then
> pContainer = Nothing
> Dim pceltFetched As Integer = 0
> ' Enumerate and refresh all the frames
> Do While pEnumerator.Next(1, pUnk, pceltFetched) = 0
> Try
> If IsNothing(pUnk) Then
> Exit Do
> End If
> ' Get the IWebBrowser2 interface
> pBrowser = pUnk
> Debug.WriteLine("Frame: " & pBrowser.LocationURL)
> Catch ex As Exception
> Debug.WriteLine(ex.Message)
> End Try
> pceltFetched = 0
> Loop
> pEnumerator = Nothing
> End If
> End Sub
>
> 4. Now we have the urls of the three frames, we can use the Webclient use
> the download and save the content.
> Here is the link about how to downloads data from a resource with the
> specified URI to a local file.
>
> WebClient.DownloadFile Method
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/
> frlrfsystemnetwebclientclassdownloadfiletopic.asp
>
> You may try my suggestion and let me know the result.
>
> Best regards,
>
> Peter Huang
> Microsoft Online Partner Support
>
> Get Secure! - www.microsoft.com/security
> This posting is provided "AS IS" with no warranties, and confers no rights.

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