ADO Error 3001, when setting the connection

In MSDN there is a reference to this error happening with ADO Recordsets.

FIX: Setting Rst.ActiveConnection to a Recordset Causes GPF

Article: Q193093

But they say this problem has been fixed with MDAC v2.1 SP2. So you could try donloading latest and greatest MDAC to see if it resolves your problem.

Well try the connection with a recordset object, if you get the same error using the Rs object then get the latest MDAC.

I attempted to duplicate your problem:  Here is what I discovered might be the problem.

In your dll your code appears okay, as I duplicated it and it connected to my SQL Server 7.0.  In your Test.exe make sure to reference your dll and declare an obj of the dll.cls that contains your connection information, set and get, etc.  It appears as though you are trying to access the private module level variable in the class that you are using to pass the connection object through your set and get in the dll.  Try the following as an experiment and see if this doesn't work:

The dll's class code:

Option Explicit

Private m_objConn As ADODB.Connection

Public Property Get objConn() As ADODB.Connection
    Set objConn = m_objConn
End Property
Public Property Set objConn(cn As ADODB.Connection)
    Set objConn = cn
End Property

Private Sub Class_Initialize()
    Set m_objConn = New ADODB.Connection

    ' substitute your own connection string here
    m_objConn.ConnectionString = "Provider=SQLOLEDB.1;Data Source=HAWKEYE;Initial Catalog=Northwind;User ID=sa;Password=;"
   
    m_objConn.Open
End Sub


In the test project which is added to the dll project, in the form put the following code:

Option Explicit

Private cmd As ADODB.Command
Private obj As Project1.clsdataaccess

Private Sub Form_Load()
    Set cmd = New ADODB.Command
    Set obj = New Project1.clsdataaccess

    If obj.objconn.state then
          msgbox "Connection open"
         'set the command object connection to the public
         ' connection variable in the dll class, not the
         ' module level private variable which is what
         ' you appear to be doing.
          Set cmd.ActiveConnection = obj.objconn
    End If
End Sub


Following your information, I was unable to get the same error.  However, when I used the code Set objCommand.ActiveConnection = m_objConn I got "variable not defined" as an error.

I hope this helps.

Sorry, forgot to add that you also need to make a reference to the appropriate ADO object library in your Test.exe along with the reference to your dll.

Good luck.

Hi again,

It turned out that I needed to open the connection object in the dll, after I set the connection property (I presumed that as I was passing the dll an already opened object from the exe, that I wouldn't need to do this??)

Thanks for your help - that was a tricky one!

Hi mdelmar,
It appears that you have forgotten this question. I will ask Community Support to close it unless you finalize it within 7 days. I will ask a Community Support Moderator to:

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DanRollins -- EE database cleanup volunteer