Unable to cast COM object of type 'System._

Unable to cast COM object of type 'System.__ComObject' Error Message

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D. Janknecht - 17 Jun 2005 13:24 GMT

Hello,

after turning my Serviced Component into a server-application, i cannot call
any methods and the following error message occurs:

"Unable to cast COM object of type 'System.__ComObject' to interface type
'ESServerTest.IServer'. This operation failed because the QueryInterface
call on the COM component for the interface with IID
'{70924D77-7D69-3C0C-A5D8-3C6FD029F799}' failed with HRESULT: 0x80004002
(Schnittstelle nicht unterstützt (Exception from HRESULT: 0x80004002
(E_NOINTERFACE)))."

Where "Schnittstelle nicht unterstützt" means "Interface not supported"

I'm using VS2005 Beta2. Here is the code of my ServicedComponent:

namespace ESServerTest
{
[Guid("CAAD4F2A-52E8-4b7c-82DE-0B013A010900")]
public interface IServer
{
string SaySomething(string text);
}
[ComVisible(true)]
[Guid("3725FED2-C5B1-4789-9125-1B3E32CA7D9E")]
[ComponentAccessControl(true)]
[ClassInterface(ClassInterfaceType.None)]
public class ESServer : ServicedComponent, IServer
{
[ComVisible(true)]
public string SaySomething(string text)
{
return text;
}
}
}

I try to call the method "SaySomething" by:
ESServerTest.ESServer test = new ESServerTest;
MessageBox.Show(test.SaySomething("Test"));

I've already installed the assembly into the GAC, so this isn't the problem.
Does somebody have an idea?

Thanks,
Dirk

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cyberzuhalter@hotmail.com - 11 Jul 2005 15:53 GMT

Dirk,

Have you found a solution to your problem? I'm having an IDENTICAL problem now.

Thanks for any help.

-Boby

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D. Janknecht - 25 Jul 2005 11:09 GMT

Sorry Boby,

no solution so far. We have posted it as a bug...

Dirk

> Dirk,
>
[quoted text clipped - 9 lines]
> Comprehensive, categorised, searchable collection of links to ASP &
> ASP.NET resources...

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D. Janknecht - 27 Jul 2005 10:21 GMT

Hi Boby,

i removed all GUIDs and "ComVisible" attributes from the class, then
switched the [assembly: ComVisible(true)] attribute in the
AssemblyInfo-File to 'true'.

Now it works.

Dirk

> Sorry Boby,
>
[quoted text clipped - 15 lines]
>> Comprehensive, categorised, searchable collection of links to ASP &
>> ASP.NET resources...

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Michael Dyrnaes - 03 Aug 2005 06:05 GMT

Has anyone found a solution to this problem ???

Visual Studio 2005 Enhanced Edition Beta 2.

1. On the right column of the development screen I select the tab DATA
SOURCE.
2. Click on the link in window above that says ADD NEW DATA SOURCE.
3. Click on the data source type WEB SERVICES and then click on the
NEXT button.
4. In the URL field I type in the URL and then I click on the GO
button.
5. WEB DISCOVERY SERVICE dialog and I click on the YES button.
6. I enter the URL, USER NAME, PASSWORD, DOMAIN and click on the YES
button.
7. The error message above appears in a window with the heading "Web
services
found at this URL" and the dialog reappears with everything except the
PASSWORD visible.

Error Message ...

"Unable to cast COM object of type 'System.__ComObject' to interface
type 'EnvDTE.IVsExtensibility'. This operation failed because the
QueryInterface call on the COM component for the interface with IID
'{3C536122-57B1-46DE-AB34-ACC524140093}' failed with HRESULT: 0x80004002
(No such interface supported (Exception from HRESULT: 0x80004002
(E_NOINTERFACE)))."

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Fidias Gil de Montes - 15 Sep 2005 23:49 GMT

I have a similar problem. I receive the message:

************** Exception Text **************
System.InvalidCastException: Unable to cast object of type
System.__ComObject to type System.Data.DataSet.

Server stack trace:
at servidor.IclaseSvr.prueba2(DataSet ds)
at
System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(MethodBase
mb, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext,
Object[]& outArgs)
at
System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext)

Exception rethrown at [0]:
at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage
reqMsg, IMessage retMsg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData&
msgData, Int32 type)
at servidor.claseSvr.prueba2(DataSet ds)
at cliente.frmPrincipal.Button1_Click(Object sender, EventArgs e) in
d:\My Documents\Visual Studio
Projects\ErrorComObject\cliente\frmPrincipal.vb:line 113
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons
button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg,
IntPtr wparam, IntPtr lparam)

when the client calls the server. However if the Application COM's identity
is the same that the client's user ID, all works fine.

My server code is:

<SecureMethod()> _
Public Class claseSvr
Inherits ServicedComponent
Implements IclaseSvr

Public Sub prueba2(ByVal ds As DataSet) _
Implements IclaseSvr.prueba2
'<My Code Here>
End Sub

End Class

Public Interface IclaseSvr
Sub prueba2(ByVal ds As DataSet)
End Interface

My Client code:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Dim svr As New servidor.claseSvr
Dim ds As DataSet

ds = New DataSet
'<some code>
svr.prueba2(ds)
End Sub

Some guess?

Thanks,

Fidias Gil de Montes

> Hello,
>
[quoted text clipped - 42 lines]
> Thanks,
> Dirk

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Unable to cast COM object of type 'System.__ComObject' Error Message

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