.NET Framework 4.6 and 4.5
Closes the connection to the database.
The Close method rolls back any pending transactions. It then releases the connection to the connection pool, or closes the connection if connection pooling is disabled.
An application can call Close more than one time without generating an exception.
Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1
.NET Framework Client Profile
Supported in: 4, 3.5 SP1
Supported in: 3.0, 2.0, 1.0