Commented Unassigned: Multiple NetOffice Excel Add-ins [21946]

Hi,

I am currently having a problem with 2 excel add-ins built with NetOffice version 1.6 and 1.7.2. These two add-ins are being developed on the same machine The second add-in that loads (loading seems to be based on the addin progid, and then in alphabetical order) will throw an exception in the __IDTExtensibility2.OnConnection__ method. The method looks like this:

```
void IDTExtensibility2.OnConnection(object application, ext_ConnectMode connectMode, object addInInst, ref Array custom)
{
try
{
this.excelApplication = new Excel.Application(null, application);
...do some work...
}
catch (Exception exception)
{
...
}
}
```

The exception is thrown where the new '''Excel.Application''' is being created. The message of the exception is the following:

_Object reference not set to an instance of an object._

Does anybody have an idea what may be the cause of this problem? Could the problem be that the two add-ins do not use the same version? one is using version 1.6, the other is using version 1.7.2.
Comments: ** Comment from web user: samgerene **

Dear Sebastian,

Thanks for the fast reply, I will update the version of NetOffice of the add-in that is under my control to the latest version and do as you suggested regarding creating an "own core".

Regards, Sam