PRB: 'Unspecified Error' Err Using ADO Data Marshalling w/ DCOM

MORE INFORMATION

Steps to Reproduce Behavior

• Creating the SQL Server table.
• Creating the Visual Basic ActiveX .dll.
• Creating the Visual Basic Standard EXE.
• Setting up Microsoft Transaction Server Explorer.

Creating the SQL Server Table

1. Start ISQL_w and execute the following script to create the test table for the ADO sample code. After executing the script you may close ISQL_w:

         CREATE TABLE dbo.TestTable_SN
         (
            col1 varchar (25) NOT NULL DEFAULT (user_name()),
            col2 datetime NOT NULL DEFAULT (getdate())
         )
         GO
   
   					

Start Visual Basic and Create an ActiveX DLL Project

1. From the Project menu, choose References and select the Microsoft Data Access Objects 2.0 Library and the Microsoft Data Access Objects Recordset 2.0 Library.
2. Paste the following code in the <Class> for the project:

         Private strSQL As String
         Private strConnect As String
         Dim ADOCn As ADODB.Connection
   
         Public Function GetData() As ADOR.Recordset
          If Not ADOCn Is Nothing Then
           Else
            Err.Raise vbObjectError + 98, "ADOGetData", "No valid Connection"
           End If
           Dim ADORs As ADOR.Recordset
           Set ADORs = New ADOR.Recordset
           With ADORs
              .CursorLocation = adUseClient
              .ActiveConnection = ADOCn
              .CursorType = adOpenForwardOnly
              .LockType = adLockBatchOptimistic 'batch updates.
              .Open strSQL
           End With
   
            'DisConnect the Recordset from the connection.
           Set ADORs.ActiveConnection = Nothing
           Set GetData = ADORs
           Set ADORs = Nothing
         End Function
   
         Private Property Get ConnectStr() As String
             ConnectStr = strConnect
         End Property
   
         Private Property Let ConnectStr(strCn As String)
           strConnect = strCn
         End Property
   
         Public Property Get SQL() As String
           SQL = strSQL
         End Property
   
         Public Property Let SQL(nSQL As String)
           strSQL = nSQL
         End Property
   
         Public Sub UpdateRS(ByVal ClientRs As ADOR.Recordset)
             Dim ADORs As New ADOR.Recordset
             If Not ADOCn Is Nothing Then
             Else
              Err.Raise vbObjectError + 99, "ADOUpdate", "No valid Connection"
             End If
             ADORs.ActiveConnection = strConnect
             ADORs.Open ClientRs
             ADORs.UpdateBatch
   
         End Sub
   
         Public Sub ADOConnect(strConnect As String, Optional CnTimeOut As _
             Integer = 20)
            Set ADOCn = New ADODB.Connection
            With ADOCn
               .Provider = "MSDASQL"  '"SQLOLEDB"
               .CursorLocation = adUseClient
               .ConnectionString = strConnect
               .CommandTimeout = CnTimeOut
               .Open
            End With
            ConnectStr = ADOCn
          End Sub
   
   					

3. Rename the Class to ADOData.
4. Rename the Project to ADOProc.
5. Compile the project and an ActiveX DLL named ADOProc.dll will be created and registered.

Creating a New Standard EXE Project to Call the DLL

1. Open a new project and create a Standard EXE application.
2. From the Project menu, choose References and select the Microsoft Data Access Objects 2.0 Library and the Microsoft Data Access Objects Recordset 2.0 Library and ADOProc.
3. Add a Command button to the form.
4. Add a text box to the form and change the name to txtValue.
5. Paste the following code into the General Declarations section of the form: NOTE: You may need to change the connect string to work in your environment.

         Const strConnect = "Driver={SQL _
            Server};Server=(local);Database=Pubs;Uid=Sa;Pwd="
   
         Private Sub Command1_Click()
            On Error GoTo ErrorHandler
   
            Dim ADORs As ADOR.Recordset
            Dim objADOData As ADOProc.ADOData
            Dim rField As ADODB.Field
            Dim iValue As Byte
   
            ' Instantiate the Data Object.
            Set objADOData = New ADOProc.ADOData
            With objADOData
               .SQL = "SELECT * FROM TestTable_SN"
               .ADOConnect strConnect, 15 'Establish connection.
            End With
   
            Set ADORs = New ADOR.Recordset
            ' Rtrn the Resultset from Data object.
            Set ADORs = objADOData.GetData
            ' The Resultset is disConnected at this point.
   
            ADORs.AddNew
   
            ' Fails (Remotely - DCOM) if quotes around the
            ' Date value instead of pound sign.
            ADORs(0) = App.EXEName
            ADORs(1) = #12/12/98#
   
            ADORs.MarshalOptions = adMarshalModifiedOnly
            objADOData.UpdateRS ADORs
            MsgBox "Data Changed", vbOKOnly, "Data Object"
          Exit Sub
   
          ErrorHandler:
          MsgBox "Change Failed:" & vbCrLf & Err.Number & vbCrLf & _
            Err.Description, vbOKOnly, "Data Object"
          Debug.Print Err.Number & vbCrLf & Err.Description
          Exit Sub
          End Sub
   
   					

Setting up Microsoft Transaction Server Explorer

1. Compile the Client application (the Standard EXE) and build a setup/install package with the Application Setup Wizard in Visual Basic 5.0 and the Package and Deployment Wizard for Visual Basic 6.0.
   
   NOTE: For more information about using these, please refer to the Online help.
2. Copy the install/setup program for the Client application to the remote computer and run the install.
3. On the server, start Microsoft Transaction Server Explorer.
4. Navigate to Microsoft Transaction Server, Computers, My Computer, Packages Installed.
5. Right-click Packages Installed and select New Package.
6. Create a new Empty Package, enter a name for the package, click Next twice, then click Finish.
7. Navigate to your new package by name then navigate to the Component folder.
8. Click Component then right-click Component. Select New-Component then choose "Import Components that are already Registered."
9. Scroll down to the ADOProc.ADOData component and click Finish.
10. Export the package to the second computer by right-clicking the Package folder (for your new package) and selecting Export.
11. Browse to the computer to export the package and then name the exported package.
12. On the client computer (where you exported the package), run the client Setup .exe to install/register the package on the remote client.
13. When the Client application is installed run the application and you should not see any errors.
14. Change the Client application to see the error by modifying the Visual Basic code as indicated in the source. That is, put quotes around the date value and recompile the Client application. Next, copy the client EXE file to the remote computer and rerun it. You should see an 'Unspecified Error' error message this time.