Calling COM+ component from webservice

Discussion in 'ASP .Net' started by Greg Busby, Jan 18, 2005.

  1. Greg Busby

    Greg Busby Guest

    I am a newbie to ASP.NET and webservices. I have a webservice that is
    calling a C# dll. This dll then calls methods in a VB COM+ component.
    The COM+ component is not instantiating correctly. The return value of
    the called function is an ADO recordset. Looking at the value of the
    variable in the watch window, it is undeclared. So, the function is not
    completing. I ran this code from a straight WinForms application and it
    worked fine. Is there something about webservices that would prevent me
    from doing what I am attempting? I got the following message in he
    output window:

    Interop.Grading QueryInterface for interface Grading._clsGrading
    failed. Since the calling of the COM+ component works fine in a
    WinForms app, is the problem one of security/permissions?

    Thanks in advance for any assistance.

    Greg



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    Greg Busby, Jan 18, 2005
    #1
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  2. Greg Busby

    bruce barker Guest

    unlike Winforms (or WebForms which support the aspcompat flag), calling STA
    (vb6) com components is not directly supported with webservices. you need
    to create your own STA thread to manage calls to the component. you only
    other option is to host the com object in a com+ application (though there
    is a big performance cost).

    -- bruce (sqlwork.com)


    "Greg Busby" <> wrote in message
    news:%23sBY%23ha$...
    | I am a newbie to ASP.NET and webservices. I have a webservice that is
    | calling a C# dll. This dll then calls methods in a VB COM+ component.
    | The COM+ component is not instantiating correctly. The return value of
    | the called function is an ADO recordset. Looking at the value of the
    | variable in the watch window, it is undeclared. So, the function is not
    | completing. I ran this code from a straight WinForms application and it
    | worked fine. Is there something about webservices that would prevent me
    | from doing what I am attempting? I got the following message in he
    | output window:
    |
    | Interop.Grading QueryInterface for interface Grading._clsGrading
    | failed. Since the calling of the COM+ component works fine in a
    | WinForms app, is the problem one of security/permissions?
    |
    | Thanks in advance for any assistance.
    |
    | Greg
    |
    |
    |
    | *** Sent via Developersdex http://www.developersdex.com ***
    | Don't just participate in USENET...get rewarded for it!
     
    bruce barker, Jan 18, 2005
    #2
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