DOCUMENT:Q171824  11-JAN-2001  [vbwin]
TITLE   :FIX: Crash in INET Control Downloading Page Multiple Times
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:WINDOWS:5.0
OPER/SYS:
KEYWORDS:kbVBp500 kbVS97sp2fix kbvbp500sp2fix

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The information in this article applies to:

 - Microsoft Visual Basic Learning Edition for Windows, version 5.0 
 - Microsoft Visual Basic Professional Edition for Windows, version 5.0 
 - Microsoft Visual Basic Enterprise Edition for Windows, version 5.0 
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SYMPTOMS
========

The Internet Transfer Control crashes if you call the Execute method that causes
the GetChunk function to be called repeatedly.

This problem only occurs with the Execute method when GetChunk is called
repeatedly, asking for small buffers (for instance, 1K), until the total
download is retrieved. If GetChunk is called only once and asks for a very large
buffer (for instance, 100K), the problem disappears.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual Studio 97 Service
Pack 2.

For more information on the Visual Studio 97 Service Pack 2, please see the
following article in the Microsoft Knowledge Base:

   Q170365 : INFO: Visual Studio 97 Service Packs - What, Where, and Why

For a list of the Visual Basic 5.0 bugs that were fixed in the Visual Studio 97
Service Pack 2, please see the following article in the Microsoft Knowledge
Base:

   Q171554 : INFO: Visual Basic 5.0 Fixes in Visual Studio 97 Service Pack 2

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Run Visual Basic or, if Visual Basic is already running, choose New Project
   from the File menu (ALT, F, N). Form1 is created by default.

2. Place an Internet Transfer Control (Inet1) on Form1 and add the following
   code:

        Private Sub Inet1_StateChanged(ByVal State As Integer)
           Dim strMess As String ' Message variable.
           Select Case State
           ' ... Other cases not shown.

           Case icResponseCompleted ' 12
               Dim vtData As Variant ' Data variable.
               Dim strData As String: strData = ""
               Dim bDone As Boolean: bDone = False

               ' Get first chunk.
               vtData = Inet1.GetChunk(1024, icString)

               Do While Not bDone
                   strData = Data & vtData
                   ' Get next chunk.
                   vtData = Inet1.GetChunk(1024, icString)
                   If Len(vtData) = 0 Then
                       bDone = True
                   End If
               Loop

               txtdata.Text = strData

         End Sub
     

3. Place a CommandButton (Command1) on Form1, and add the following code:

         Private Sub Command4_Click()
            Inet1.Execute "ftp://Tony's Server", "dir"
         End Sub
     

4. From the Run menu, click Start (ALT, R, S), or press the F5 key to run the
   program. Press the Command1 button multiple time to see the crash.

Additional query words: kbDSupport

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Keywords          : kbVBp500 kbVS97sp2fix kbvbp500sp2fix 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVBA500 kbVB500
Version           : WINDOWS:5.0
Issue type        : kbbug
Solution Type     : kbfix

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Copyright Microsoft Corporation 2001.