C# – ASP.Net Com-InterOp Excel Generation issue when hosting

asp.netccom-interopwindows-server-2008

In my ASP.Net application I'm generating a Excel file using MsExcel Object Libby (Com-InterOp) . The application worked fine in the VS dev. environment.

But when I host it in the server I'm getting following error, if I'm no user is logged in to the server through Remote desktop Connection.

"Retrieving the COM class factory for component with CLSID {00024500-0000-0000-C000-000000000046} failed due to the following error: 8000401a The server process could not be started because the configured identity is incorrect. Check the username and password. (Exception from HRESULT: 0x8000401A)."

I've set DCOM configurations as well. The strange thing is that at least one user should be connected to the server through RDC. If so everyone can generate excels. If not above error throws. Rest of the functionality of the application works fine.

The server is Windows Server 2008, IIS7. And the users connecting the application through a VPN.

Has any one experienced a issue like this?

Thanks in advance.

Best Answer

In the end I created user who is admin on the computer with the web service, and then I set this user like shown on the screen below:

enter image description here

That worked. And we didn't have to let the computer be locked.

Related Solutions

C# – How to properly clean up Excel interop objects

Excel does not quit because your application is still holding references to COM objects.

I guess you're invoking at least one member of a COM object without assigning it to a variable.

For me it was the excelApp.Worksheets object which I directly used without assigning it to a variable:

Worksheet sheet = excelApp.Worksheets.Open(...);
...
Marshal.ReleaseComObject(sheet);

I didn't know that internally C# created a wrapper for the Worksheets COM object which didn't get released by my code (because I wasn't aware of it) and was the cause why Excel was not unloaded.

I found the solution to my problem on this page, which also has a nice rule for the usage of COM objects in C#:

Never use two dots with COM objects.

So with this knowledge the right way of doing the above is:

Worksheets sheets = excelApp.Worksheets; // <-- The important part
Worksheet sheet = sheets.Open(...);
...
Marshal.ReleaseComObject(sheets);
Marshal.ReleaseComObject(sheet);

POST MORTEM UPDATE:

I want every reader to read this answer by Hans Passant very carefully as it explains the trap I and lots of other developers stumbled into. When I wrote this answer years ago I didn't know about the effect the debugger has to the garbage collector and drew the wrong conclusions. I keep my answer unaltered for the sake of history but please read this link and don't go the way of "the two dots": Understanding garbage collection in .NET and Clean up Excel Interop Objects with IDisposable

.net – Retrieving the COM class factory for component with CLSID {XXXX} failed due to the following error: 80040154

In VS - project properties - in the Build tab - platform target =X86

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