SQL Server custom instance Database Access

When installing SQL Server,

After the installation ends, the component information is updated and the task can only be ended,

The SQL server installed here cannot be uninstalled and repaired,

Only new instances can be used for installation!

However,

<Add key = "connectionstr" value = "User ID = sa; Password =; initial catalog = TM; Data Source = localhost; Connect timeout = 30"/>

The connection settings above cannot be connected.

Later I studied it for half a day and it was an instance problem.

Change

<Add key = "connectionstr" value = "User ID = sa; Password =; initial catalog = TM; Data Source = localhost \ hzc; Connect timeout = 30"/>

Hzc is the name of my instance.