How to check which locks are held on a table?

 use a Dynamic Management View (DMV) to capture locks as well as the object_id or partition_id of the item that is locked.

(MUST switch to the Database you want to observe to get object_id)

SELECT
t1.resource_type,
t1.resource_database_id,
t1.resource_associated_entity_id,
t1.request_mode,
t1.request_session_id,
t2.blocking_session_id,
o1.name 'object name',
o1.type_desc 'object descr',
p1.partition_id 'partition id',
p1.rows 'partition/page rows',
a1.type_desc 'index descr',
a1.container_id 'index/page container_id'
FROM sys.dm_tran_locks as t1INNER JOIN sys.dm_os_waiting_tasks as t2
        ON t1.lock_owner_address = t2.resource_addressLEFT OUTER JOIN sys.objects o1 on o1.object_id = t1.resource_associated_entity_idLEFT OUTER JOIN sys.partitions p1 on p1.hobt_id = t1.resource_associated_entity_idLEFT OUTER JOIN sys.allocation_units a1 on a1.allocation_unit_id = t1.resource_associated_entity_id