BUG: Error 0x800A02E0 "Cannot Save an Uninitialized Class" on Visual Basic Component (272490)


The information in this article applies to:

  • Microsoft Visual Basic Enterprise Edition for Windows 6.0
  • Microsoft Visual Basic Professional Edition for Windows 6.0
  • Microsoft Internet Information Server 4.0
  • Microsoft Internet Information Server 5.0
  • Microsoft Active Server Pages
This article was previously published under Q272490

SYMPTOMS

When you create a Visual Basic ActiveX dynamic-link library (DLL) from Active Server Pages (ASP) or from another Microsoft Transaction Server component with CreateInstance and call a method on it that writes to a PropertyBag object, you may receive the following error message when you call the WriteProperty method on the PropertyBag:
Error Type:
SomeComponent (0x800A02E0)
Cannot save an uninitialized class. You must use the global InitProperties method to initialize the class, or load the class from a PropertyBag before trying to save it.
This problem does not occur when you create the component from Visual Basic with the New keyword.

CAUSE

This problem occurs because the IPersistStream::InitNew method is not called on the component that is saved. When the component is created from Visual Basic with New, the Visual Basic runtime calls InitNew for you.

RESOLUTION

To work around this problem, create the component through a factory component in Visual Basic so that Visual Basic creates the component and calls InitNew on the IPersistStreamInit interface.

STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

MORE INFORMATION

Steps to Reproduce Behavior

  1. Create a new Visual Basic ActiveX DLL. Rename the project "MyBag" and the class "CBag".
  2. Set the persistable property of CBag to "1 persistable".
  3. Add the following code and compile:
    Private n As Long

Private Sub Class_InitProperties()
    n = 12
End Sub

Private Sub Class_ReadProperties(PropBag As PropertyBag)
    n = PropBag.ReadProperty("n")
End Sub

Private Sub Class_WriteProperties(PropBag As PropertyBag)
    PropBag.WriteProperty "n", n
End Sub

Public Function Serialize() As Byte()

   Dim pbgState As PropertyBag
   
   Set pbgState = New PropertyBag
   
   pbgState.WriteProperty "TestSerialize", Me
   
   Serialize = pbgState.Contents
   
   Set pbgState = Nothing
  
End Function
  4. Create an ASP page named Mybag.asp, and paste the following code:
    <%
	set bag = Server.CreateObject("Bag.CBag")
	bag.Serialize
	response.write "Done" 
%>
  5. In your browser, open the page. You receive the above-mentioned error.

Workaround

  1. Add another class to the project named CBagFactory.
  2. Add a function called CreateBag as follows:
    Public Function CreateBag() As CBag
    Set CreateBag = New CBag
End Function
  3. Recompile the DLL.
  4. Replace the ASP code with the following code:
    <%
	set fac = Server.CreateObject("Bag.CBagFactory")
	set bag = fac.CreateBag
	bag.Serialize
	response.write "Done" 
%>
  5. In your browser, run the ASP page. You do not receive the error message.

REFERENCES

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

241896 PRB: Threading Issues with Visual Basic 6.0 ActiveX Components

Modification Type:MinorLast Reviewed:7/13/2004
Keywords:kbbug kberrmsg kbnofix KB272490
©2004 Microsoft Corporation. All rights reserved.