PRB: 80004005 Unspecified Error When Passing Disconnected Recordset from MTS to ASP (237536)

SYMPTOMS

When passing a disconnected ActiveX Date Objects (ADO) Recordset from a Component Object Model (COM) component inside a Microsoft Transaction Server (MTS) Server Package/COM+ Application to Active Server Pages (ASP), you may receive one of the following error messages:

error '80004005'
Unspecified error
/xxx.asp, line x

-or- (with ASP error handling)

Error Number : 13 - Source : Microsoft VBScript runtime error - Type mismatch

-or- (after multiple tries)

Microsoft VBScript runtime error '800a0007'
Out of memory: 'obj.TestRS'
/xxx.asp, line x

CAUSE

An error occurs because the fields in the disconnected recordset have been defined as adVariant, and ADO cannot marshal certain data types within adVariant across process boundaries (in this case, between InetInfo and MTS or COM+). ADO marshaling cannot convert data of the following types when the field type is set to adVariant:

DBTYPE_BSTR = 8,
DBTYPE_IDISPATCH = 9,
DBTYPE_VARIANT = 12,
DBTYPE_IUNKNOWN = 13,
DBTYPE_ARRAY = 0x2000,
DBTYPE_BYREF = 0x4000,

Please note that the following types are not to be used for Automation when using adVariant, as documented (search for the Topic "Type Indicators" in the Microsoft Data Access Components 2.5 SDK - OLE DB Programmer's Reference in the MSDN library at http://msdn.microsoft.com/library/psdk/dasdk/olpr0vu6.htm):

// The following values exactly match VARENUM
// in Automation but cannot be used in VARIANT.
DBTYPE_I8 = 20,
DBTYPE_UI8 = 21,
DBTYPE_GUID = 72,
DBTYPE_VECTOR = 0x1000,
DBTYPE_FILETIME = 64,
DBTYPE_RESERVED = 0x8000,

RESOLUTION

When trying to pass values of the types mentioned above, such as strings (BSTR), you must declare those field types explicitly instead of using adVariant.

Example

    rs.Fields.Append "ID", adVariant 'this works since it is an Integer
    rs.Fields.Append "fname", adVarChar, 50
    rs.Fields.Append "lname", adVarChar, 50

MORE INFORMATION

Steps to Reproduce Behavior

In Microsoft Visual Basic 6.0, create a new ActiveX DLL project.
Add the following references to the project:
Microsoft Transaction Server Type Library
(NOTE: Under Windows 2000, select COM+ Services Type Library instead of Microsoft Transaction Server Type Library)

Microsoft ActiveX Data Objects Library

Copy and paste the following code into the Class Module:

Public Function TestRS() As Variant
    Dim rs As ADODB.Recordset
    Set rs = GetObjectContext.CreateInstance("ADODB.Recordset")
    rs.Fields.Append "ID", adVariant
    rs.Fields.Append "fname", adVariant
    rs.Fields.Append "lname", adVariant
    rs.CursorLocation = adUseClient
    rs.Open
    rs.AddNew
        rs(0) = 1
        rs(1) = "Yuri"
        rs(2) = "Lausberg"
    rs.Update
    Set TestRS = rs.Clone
    rs.Close
    Set rs = Nothing
    GetObjectContext.SetComplete
End Function

Set the Class Property MTSTransactionMode = 1 NoTransactions.
Compile the DLL.
Add the DLL to an MTS Server Package or a COM+ Application.

Copy and paste the following ASP script into a new ASP file.

<%
  On Error Resume Next 
  Set obj = Server.Createobject("project1.class1")
  Set rs = obj.TestRS
  Response.Write rs(1)
  If Err.Number > 0 Then
    Response.Write "<B>Unable to read field value</B><P>"
    Response.Write "Error Number : "& Err.Number
    Response.Write " - Source : " & Err.Source
    Response.Write " -  " & Err.Description & "<P>"
  Else
    Response.Write rs(2)
  End If
  rs.Close
  Set rs = Nothing
%>

Request the ASP file from a browser, and the following error appears:
Unable to read field value

Error Number : 13 - Source : Microsoft VBScript runtime error - Type mismatch