MSQUERY: DDE Commands Available Only on System Channel (125492)


The information in this article applies to:

  • Microsoft Excel for Windows 95
  • Microsoft Excel for Windows 5.0
  • Microsoft Query
This article was previously published under Q125492

SYMPTOMS

When you use an application that supports dynamic data exchange (DDE) to initiate a DDE conversation with Microsoft Query, a DDE command that you use may fail to complete, may return an error message, or may return unexpected results.

CAUSE

This behavior occurs if you initiate a DDE conversation using a query channel and if you use a DDE command that is only supported on a system channel.

You can use a system channel to establish a DDE conversation with Microsoft Query to return general and query-related information. You use a query channel to establish a DDE conversation with a specific query in Microsoft Query. The following is a list of the DDE commands that you can use with Microsoft Query. The commands marked with an asterisk (*) are commands that are only supported on a system channel and that cannot be used on a query channel:

Activate*
AllowEdit
BuildSQL*
Close
Command*
Exit*
Fetch and Fetch.Advise
Fetch.Unadvise
Logoff*
Logon*
ODBCLogon*
Open*
QueryNow
SaveAs
SetWindowState
UserControl*
ViewPane

WORKAROUND

To avoid returning an error when you use one of the Microsoft Query DDE commands that is only supported on a system channel, use a system channel instead of a query channel in the DDE conversation. The following Visual Basic, Applications Edition, examples show how to establish a DDE conversation with Microsoft Query using either a system channel or a query channel.

System Channel

Sub UsingSystemChan()

Dim chan As Integer
Dim sql As String

   ' Establish DDE conversation using system channel
   chan = DDEInitiate("MSQUERY", "System")

   ' logon using NWind data source
   DDEExecute chan, "[Logon('NWind')]"

   ' Execute an SQL query to retrieve all records from Customer table
   DDEExecute chan, "[Open('SELECT Custmr_ID FROM Customer')]"

   'Return data to Sheet1 at cells A1:A63
   DDEExecute chan, "[Fetch('Excel', 'Sheet1', 'R1C1:R63C1', 'All')]"

   ' Close the DDE channel
   DDETerminate chan

End Sub

Query Channel

Sub UseQueryChannel()

Dim chan As Integer
Dim NRows, NCols

   ' Establish DDE conversation using query channel
   ' ** Note that QUERY1 must be open in Microsoft Query
   ' in order for the following command to work
   chan = DDEInitiate("MSQUERY", "query1")

   'Determine the number of rows and columns in query1
   NRows = DDERequest(chan, "NumRows")
   NCols = DDERequest(chan, "NumCols")

   ' Return the data in Query1 to Sheet1 starting at A1.
   ' ** The following two lines should be entered on one line.
   DDEExecute chan,"[Fetch('Excel', 'Sheet1', 'R1C1:R" & NRows(1) & "C"
    & NCols(1) & "', 'All')]"

   ' Close the DDE channel
   DDETerminate chan

End Sub
Microsoft provides examples of Visual Basic for Applications procedures for illustration only, without warranty either expressed or implied, including, but not limited to the implied warranties of merchantability and/or fitness for a particular purpose. The Visual Basic procedures in this article are provided 'as is' and Microsoft does not guarantee that they can be used in all situations. While Microsoft Support professionals can help explain the functionality of a particular macro, they will not modify these examples to provide added functionality, nor will they help you construct macros to meet your specific needs. If you have limited programming experience, you may want to consult one of the Microsoft Solution Providers. Solution Providers offer a wide range of fee-based services, including creating custom macros. For more information about Microsoft Solution Providers, call Microsoft Customer Information Service at (800) 426-9400.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft Products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

REFERENCES

For more information about individual DDE commands, such as the Activate command, choose the Search button in Help and type:

DDE commands

Modification Type:MinorLast Reviewed:10/11/2006
Keywords:kbinterop KB125492
©2004 Microsoft Corporation. All rights reserved.