The information in this article applies to:
- Microsoft Visual Basic Control Creation, Learning, Professional, and
Enterprise Editions for Windows, version 5.0
SYMPTOMS
The Internet Transfer Control 5.0 "POST" request does not work as described
in the documentation provided by Microsoft. The input data parameter of the
Execute method is not being sent correctly to the web server when "POST" is
specified.
RESOLUTION
The Internet Transfer Control 5.0 "POST" request does not work from Visual
Basic 5.0. You need to use the WinInet APIs that are included with the
ActiveX SDK to PostData to your server. Specifically, the InternetOpen,
InternetConnect, HttpOpenRequest, and HttpSendRequest are the WinInet APIs
you need to use. In the sample code below, you will connect to //webserver
then post to page /generic.asp.
- Start a new Standard EXE project. Form1 is added by default.
- Add the following code to the general declarations section of Form1:
Private Declare Function InternetOpen Lib "wininet.dll" _
Alias "InternetOpenA" _
(ByVal lpszCallerName As String, _
ByVal dwAccessType As Long, _
ByVal lpszProxyName As String, _
ByVal lpszProxyBypass As String, _
ByVal dwFlags As Long) As Long
Private Declare Function InternetConnect Lib "wininet.dll" _
Alias "InternetConnectA" _
(ByVal hInternetSession As Long, _
ByVal lpszServerName As String, _
ByVal nProxyPort As Integer, _
ByVal lpszUsername As String, _
ByVal lpszPassword As String, _
ByVal dwService As Long, _
ByVal dwFlags As Long, _
ByVal dwContext As Long) As Long
Private Declare Function HttpOpenRequest Lib "wininet.dll" _
Alias "HttpOpenRequestA" _
(ByVal hInternetSession As Long, _
ByVal lpszVerb As String, _
ByVal lpszObjectName As String, _
ByVal lpszVersion As String, _
ByVal lpszReferer As String, _
ByVal lpszAcceptTypes As Long, _
ByVal dwFlags As Long, _
ByVal dwContext As Long) As Long
Private Declare Function HttpSendRequest Lib "wininet.dll" _
Alias "HttpSendRequestA" _
(ByVal hHttpRequest As Long, _
ByVal sHeaders As String, _
ByVal lHeadersLength As Long, _
ByVal sOptional As String, _
ByVal lOptionalLength As Long) As Boolean
Private Declare Function InternetCloseHandle Lib "wininet.dll" _
(ByVal hInternetHandle As Long) As Boolean
- From the Project menu, choose Components, and then select the Internet
Transfer Control 5.0 into the project if it is not already loaded.
- Place an Internet Transfer Control 5.0 (Inet1) on Form1.
- Place a CommandButton (Command1) on Form1 and add the following code:
Private Sub Command1_Click()
Dim hInternetOpen As Long
Dim hInternetConnect As Long
Dim hHttpOpenRequest As Long
Dim bRet As Boolean
hInternetOpen = 0
hInternetConnect = 0
hHttpOpenRequest = 0
'Use registry access settings.
Const INTERNET_OPEN_TYPE_PRECONFIG = 0
hInternetOpen = InternetOpen("http generic", _
INTERNET_OPEN_TYPE_PRECONFIG, _
vbNullString, _
vbNullString, _
0)
If hInternetOpen <> 0 Then
'Type of service to access.
Const INTERNET_SERVICE_HTTP = 3
Const INTERNET_DEFAULT_HTTP_PORT = 80
hInternetConnect = InternetConnect(hInternetOpen, _
"webserver", _
INTERNET_DEFAULT_HTTP_PORT, _
vbNullString, _
"HTTP/1.0", _
INTERNET_SERVICE_HTTP, _
0, _
0)
If hInternetConnect <> 0 Then
'Brings the data across the wire even if it locally cached.
Const INTERNET_FLAG_RELOAD = &H80000000
hHttpOpenRequest = HttpOpenRequest(hInternetConnect, _
"POST", _
"/generic.asp", _
"HTTP/1.0", _
vbNullString, _
0, _
INTERNET_FLAG_RELOAD, _
0)
If hHttpOpenRequest <> 0 Then
Dim lpszPostData As String
Dim lPostDataLen As Long
lpszPostData = "lname=Doe&fname=John"
lPostDataLen = Len(lpszPostData)
bRet = HttpSendRequest(hHttpOpenRequest, _
vbNullString, _
0, _
lpszPostData, _
lPostDataLen)
'Close all handles
bRet = InternetCloseHandle(hHttpOpenRequest)
End If
bRet = InternetCloseHandle(hInternetConnect)
End If
bRet = InternetCloseHandle(hInternetOpen)
End If
End Sub
- From the Run menu, choose Start (ALT, R, S) or press the F5 key to run
the program. Press the Command1 button and "lname=Doe&fname=John" will
be posted to your server.
NOTE: You will have to replace //webserver/generic.asp with your server
page that is expecting the posted information. You will also need to
replace "lname=Doe&fname=John" with the information you want posted.
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:
ARTICLE-ID: Q170365
TITLE : 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:
ARTICLE-ID: Q171554
TITLE : INFO: Visual Basic 5.0 Fixes in Visual Studio 97
Service Pack 2
MORE INFORMATION
Steps to Reproduce Behavior
- Start a new Standard EXE project. Form1 is added by default.
- From the Project menu, choose Components, and select the Internet
Transfer Control 5.0 into the project if it is not already loaded.
- Place an Internet Transfer Control 5.0 (Inet1) on Form1.
- Place a CommandButton (Command1) on Form1 and add the following code:
Private Sub Command1_Click()
Dim strURL As String, strFormData As String
strURL = "http://webserver/generic.htm"
strFormData = "fname=randy;lname=morgan"
Inet1.Execute strURL, "Post", strFormData
End Sub
- From the Run menu, choose Start (ALT, R, S) or press the F5 key to run
the program. Press the Command1 button and garbage will be posted to
"http://webserver/generic.htm".
REFERENCES
ActiveX SDK
Keywords : vb5all VBKBAX VBKBComp VBKBCtrl VBKBInt VS97FixlistSP3 VS97FixlistSP2 VB5FixlistSP2
Technology : kbole
Version : 5.0
Platform : WINDOWS
Issue type : kbbug
Solution Type : kbfix kbservicepack
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