C# 服务与 Interop.Excel 不能作为服务工作，但只能在本地工作

Question

I need help with a service in C# I am fixing. This service does (in order):

1. copies a XLSM file from a NAS folder in local WM;
2. parse this file using Microsoft.Office.Interop.Excel (vers. 15.0.4795.1000 from NuGET);
3. fill a table in a DB with data extracted from this Excel file.

This service is written with C# in VS2019 in the same VM where it should run. If I run it in debug mode with VS everything works, so I installed it in the VM but now it does not work anymore, I keep getting this error as soon as step 2 starts:

System.Exception: System.Runtime.InteropServices.COMException (0x800A03EC): Cannot access file XXXX.xslm

The file XXXX.xlsm is the file copied from NAS in the local VM and is opened in read only mode; so step 1 is correctly executed. The service runs with the same user I use to log in the VM.

It it may help, in this VM Excel 2019 is installed, and anyway it works when I run in debug mode.

Can anybody help me?

Answer 1

Are you using absolute path to access to to file?

Usually service execution folder is different than the execution folder of an normal application and depends on the execution context of the service.

If you have to use relative path try with:

AppDomain.CurrentDomain.BaseDirectory

To find the right path.

If path is ok check that the service account user has valid rights to access and (if you need that) edit the file.