To make sure that data from different tenants doesn't get mixed in multi-tenant application we can add some defensive behaviour to multi-tenant database context to build additional safety net for application developers.
The following demonstrates defensive database context and it uses the following classes:
ITenantProvider - interface for tenant providers,
DummyTenantProvider - tenant provider for demo purposes,
BaseEntity - base class for all entities,
Person - sample entity type for this demo,
CrossTenantUpdateException - exception type for operations that use data from multiple tenants,
SampleDbContext - defensive database context.
The sample below creates new instance of database context, adds two instances of Person entities that belong to different tenants and then saves changes. If cross-tenant operation exception is thrown then tenant ID-s involved to incident are written out.