Microsoft KB Archive/224424

Knowledge Base

How To Implement Visual Basic COM Objects Returning Recordsets

Article ID: 224424

Article Last Modified on 7/1/2004

---

APPLIES TO

• Microsoft Active Server Pages 4.0
• Microsoft ActiveX Data Objects 1.5
• Microsoft ActiveX Data Objects 2.0
• Microsoft ActiveX Data Objects 2.1 Service Pack 2
• Microsoft ActiveX Data Objects 2.5
• Microsoft ActiveX Data Objects 2.6
• Microsoft ActiveX Data Objects 2.7
• Microsoft Visual Basic 5.0 Learning Edition
• Microsoft Visual Basic 6.0 Learning Edition
• Microsoft Visual Basic 5.0 Professional Edition
• Microsoft Visual Basic 6.0 Professional Edition
• Microsoft Visual Basic 5.0 Enterprise Edition
• Microsoft Visual Basic 6.0 Enterprise Edition
• Microsoft Internet Information Server 4.0
• Microsoft Internet Information Services 5.0
• Microsoft Data Access Components 2.5
• Microsoft Data Access Components 2.6
• Microsoft Data Access Components 2.7

---

This article was previously published under Q224424

SUMMARY

This article describes, by example, how to implement a Visual Basic Component Object Model (COM) Object that returns a recordset to Active Server Pages (ASP).

Implementing this incorrectly can result in memory leaks or one of the following errors:

The operation requested by the application is not allowed if the object is closed.

-or-

Type Mismatch

-or-

error 'ASP 0115' - A trappable error occured in an external object

MORE INFORMATION

Use the following steps to implement a method that returns a recordset from a Visual Basic COM Object to Active Server Pages:

1. Create a Visual Basic ActiveX DLL project called PassRsPrj.
2. Add a class module and change its name to PassRsObj.

3. Implement the following method:
   
   Note You must change the UID and the PWD values to the ones that are used on your system.
   

   Public Function TestRs() as ADODB.Recordset
          Dim rsObj As ADODB.Recordset
          Dim cnObj As ADODB.Connection    
   
          set rsObj = New ADODB.Recordset         
          set cnObj = New ADODB.Connection
   
          'Open connection to database
          cnObj.Open("DSN=pubs;uid=<username>;pwd=<strong password>")
          
          'To use disconnected Recordset you must use client side cursors
          rsObj.CursorLocation = adUseClient
   
          rsObj.Open "select * from authors", cnObj, adOpenKeyset, _
             adLockOptimistic, adCmdText
          
          'Disconnected recordset
          Set rsObj.ActiveConnection = Nothing
   
          'Set return value
          Set Testrs = rsObj
          
          'Clean up resources
          cnObj.Close
          Set cnObj = Nothing
          
      End Function
                       

4. Create an ASP page with the following code:

   <%
      Dim rsTest, oTestPassRs
   
      Set oTestPassRs = Server.CreateObject("PassRsPrj.PassRsObj")
      Set rsTest = oTestPassRs.TestRs()
   
      Do 
         Response.Write ( "Value in Record = " & rsTest(1) & "<BR>" )
         rsTest.MoveNext
      Loop until rsTest.EOF
   
      rsTest.Close
      Set rsTest = Nothing
      Set oTestPassRs = Nothing
      %>
                       

REFERENCES

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

244012 INFO: Type Mismatch Errors When You Pass Parameters from ASP to a Visual Basic Component

Additional query words: error 0115

Keywords: kberrmsg kbhowto kbcodesnippet kbdatabase KB224424

---

Send feedback to Microsoft

© Microsoft Corporation. All rights reserved.