Error: CoInitialize has not been called

[AP81]

I have an multithreaded application which runs fine, until I remove a procedure which is no longer needed. I am removing all the references to ADO (as I am no longer using ADO).

When I remove this procedure, any thread I have will not run. When the thread is executed, it will give the followinf error:
CoInitialize has not been called.

Here is the code, that creates the error when removed:

procedure TfrmMain.SetADOObjects;
begin
  ADOTableCustomers.ConnectionString := connString;
  ADOTableCustomers.TableName := 'customer_msg';
  ADOTableCustomers.Open;
end;

Here is the basic layout of one of my threads(they are all similar).

Declaration:

//type for updating items --> runs in it's own thread
type TUpdateItems = class(TThread)
  protected
    procedure Execute; override;
end;

Start the thread

procedure TfrmMain.cmdPerformOperationClick(Sender: TObject);
var
  ItemThread : TUpdateItems;
begin
if optUpdateItems.Checked then
    begin
    intResult := MessageDlg('You are about to update the database with all item codes ' +
                'from the Quicken database' + #13#10 + #13#10  +
                'If you wish to update the Items codes and descriptions, click OK',
                mtInformation, [mbOK, mbCancel], 0);
    //user presses OK
    if intResult = mrOK then
      begin
        //begin importing items and descriptions
        ItemThread := TupdateItems.Create(True);
        ItemThread.FreeOnTerminate := True;
        ItemThread.Resume;
      end
    else
      exit; //exit procedure
    end;
end;

The actual thread execute:

//procedure to retrieve all items from the Quicken database
procedure TUpdateItems.Execute;
var
  strTicket : WideString;
  strXMLRequest, strXMLResponse : String;
  //Create the RequestProcessor object
  qbXMLCOM : TRequestProcessor2;
  blnSessionBegun : Boolean;   //utility variable
begin
  frmMain.lblAdminErrorMsg.Caption := '';
  Try //begin error trapping
    //create new instance of TRrequestProcessor
    qbXMLCOM := TRequestProcessor2.Create(nil);
    qbXMLCOM.OpenConnection('','Update Database Inventory');
    strTicket := qbXMLCOM.BeginSession('', QBXMLRP2Lib_TLB.qbFileOpenDoNotCare);
    //session has begun
    blnSessionBegun := True;

    //show status label
    frmMain.taStatus.Visible := True;

    //assign strXMLRequestString to XML to update all items
    strXMLRequest :=  '<?xml version="1.0" encoding="ISO-8859-1"?>' +
                      '<?qbxml version="AU3.0"?>' +
                      '<QBXML>' +
                      '<QBXMLMsgsRq onError="continueOnError">' +
                      '<ItemQueryRq requestID="1">' +
                      '</ItemQueryRq>' +
                      '</QBXMLMsgsRq>' +
                      '</QBXML>';

    //parse XML to Quickbooks qbXML parser
    strXMLResponse := qbXMLCOM.ProcessRequest(strTicket, strXMLRequest);
    qbXMLCOM.EndSession(strTicket);  //end session
    qbXMLCOM.CloseConnection;        //close connection

  Except
    on E : Exception do
      begin
        //close session and connection
        if blnSessionBegun then
          begin
            qbXMLCOM.EndSession(strTicket);
            qbXMLCOM.CloseConnection;
          end;
        frmMain.taStatus.Visible := False;    //hide status label
        frmMain.lblAdminErrorMsg.Caption := 'Error: ' + E.Message;
         exit; //stop further processing
      end;
    end;  {try}
    frmMain.taStatus.Visible := False;    //hide import label
    //process XML datastream from Quickbooks
    frmMain.SaveToXML(strXMLResponse, 'ItemUpdate.xml');
    frmMain.FilterItems;
end;

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There's no place like 127.0.0.1
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[Griffyn]

This one annoyed me a lot too when I first came across it. I'm still not 100% sure what causes it - I thought it was by referencing an ADO object prior to Application.Run was called, but I don't think that's always the case. At any rate, to fix:

uses
  ActiveX;
begin
  CoInitialize(nil);
end;

Documentation i've come across seems to insist that if you do this, you should also call CoUninitialize; as your application is shutting down and after you've destroyed all of your ADO objects.

 

[AP81]

Griffynm, I understand what you mean but do not know where to add the code:

uses
  ActiveX;
begin
  CoInitialize(nil);
end;

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There's no place like 127.0.0.1
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[Griffyn]

If you have any [/b]initialization[/b] sections in your units that create any ADO objects, then call it prior to that. If not, then create one in your main form. That should fix it.

 

[whosrdaddy]

Hi AP81,

you must call Coinitialize in the thread were you're creating your ADO objects...

don't forget to call CoUninitialize; in the thread's destructor!

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