In a previous post I wrote about an AS2 problem that I encountered after renaming the BizTalk Groupname.
In this post I digg into another AS2 problem, this time related to context properties.

Lately I have been asked to reconfigure an AS2 configuration to send messages with a predefined filename. This is easily done by selecting Transmit file name in MIME header. This checkbox can be found under the AS2 properties of the sending party. As you can see in the printscreen there is a possibility to point to a context property of which the value will be used as filename.
Simply put the context property shortname between two percent signs. If the context property wouldn’t exist you can choose to suspend the message.

After my first attempt to send a message another AS2 error showed up.

Following the errormessage something went wrong with the initialisation of the BizTalkPropertyList.
This list can be found in the BizTalkMgmt database table bt_DocumentSpec.
The AS2 encoder will query this table to look up the property configured for retrieving the filename.
So what happened? If we open this table we see a lot of columns. But for the AS2 encoder only two seems to matter: clr_namespace and schema_root_name. The error mentioned above is caused when there are two or more property schemes deployed with the same value for these fields. In other words to avoid the AS2 encoder error, the concatenation of these fields must act as a primary key within this table. Also note that the duplicate property does not necessarely have a relation to the configured filename property. Lets have a closer look. Every BizTalk developer knows that every scheme must be made unique by its targetnamespace and rootname. This garantuees that BizTalk will process every message correctly. In the bt_DocumentSpec table this value is stored as ‘msgtype’. In this case we are talking about propertyschemes. So the msgtype field value is constructed by targetnamespace#propertyname. Because a scheme lives in a .Net BizTalk Assembly there is also another .NET namespace associated with the property. Right! clr.namespace.schema_root_name. Do remember that while this is not the fully qualified name of the property it is the value where the AS2 encoder will look for.

For example, the two rows shown in the picture below will cause the error.

I wrote a sql script to easily find duplicates in the bt_DocumentSpec table.

SELECT clr_namespace + ‘.’ + schema_root_name as shortName, COUNT(*)
FROM [dbo].[bt_DocumentSpec]
WHERE xsd_type <> ”
GROUP BY clr_namespace + ‘.’ + schema_root_name
HAVING COUNT(*) > 1

If you find duplicate properties you have to rename the clr_namespace. Do this by opening the propertylist of the propertyschema you want to modify (from within visual studio). There you will find the .Net namespace. Try to keep this namespace unique for all your BizTalk projects.