Disconnecting from an Instance of SQL Server
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Azure Synapse Analytics
Manually closing and disconnecting SQL Server Management Objects (SMO) objects is not required. Connections are opened and closed as required.
Connection Pooling
When the Connect method is called, the connection is not automatically released. The Disconnect method must be called explicitly to release the connection to the connection pool. Also, you can request a non-pooled connection. You do this by setting the NonPooledConnection property of the ConnectionContext property that references the ServerConnection object.
Disconnecting from an Instance of SQL Server for RMO
Closing server connections when you are programming with RMO works slightly different from SMO.
Because the server connection for an RMO object is maintained by the ServerConnection object, this object is also used when disconnecting from an instance of Microsoft SQL Server when you program by using RMO. To close a connection by using the ServerConnection object, call the Disconnect method of the RMO object. After the connection has been closed, RMO objects cannot be used.
Example
To use any code example that is provided, you will have to choose the programming environment, the programming template, and the programming language in which to create your application. For more information, see Create a Visual C# SMO Project in Visual Studio .NET.
Closing and Disconnecting an SMO Object in Visual Basic
This code example shows how to request a non-pooled connection by setting the NonPooledConnection property of the ConnectionContext object property.
Dim srv As Server
srv = New Server
'Disable automatic disconnection.
srv.ConnectionContext.AutoDisconnectMode = AutoDisconnectMode.NoAutoDisconnect
'Connect to the local, default instance of SQL Server.
srv.ConnectionContext.Connect()
'The actual connection is made when a property is retrieved.
Console.WriteLine(srv.Information.Version)
'Disconnect explicitly.
srv.ConnectionContext.Disconnect()
Closing and Disconnecting an SMO Object in Visual C#
This code example shows how to request a non-pooled connection by setting the NonPooledConnection property of the ConnectionContext object property.
{
Server srv;
srv = new Server();
//Disable automatic disconnection.
srv.ConnectionContext.AutoDisconnectMode = AutoDisconnectMode.NoAutoDisconnect;
//Connect to the local, default instance of SQL Server.
srv.ConnectionContext.Connect();
//The actual connection is made when a property is retrieved.
Console.WriteLine(srv.Information.Version);
//Disconnect explicitly.
srv.ConnectionContext.Disconnect();
}