Connection not working but not throwing exceptions

[rngkushner]

Describe the bug

I upgraded to Microsoft.Data.SqlClient 6.1.3 and now getting "Object reference not set to an instance of an object" on every data call.

The SQLConnection object initializes but when checking connection.State or connection.ConnectionString, it throws a null reference. I believe this is the issue.

System.NullReferenceException
HResult=0x80004003
Message=Object reference not set to an instance of an object.
Source=Microsoft.Data.SqlClient
StackTrace:
at Microsoft.Data.SqlClient.SqlConnection.get_ConnectionString()

In the appsettings.json:
"db": "Data Source=MyDB;Initial Catalog=MyDB; user id=MyUser; Password=MyPassword;TrustServerCertificate=True"

Project settings

net6.0
disable
enable

``` Exception message: Stack trace:

System.NullReferenceException
HResult=0x80004003
Message=Object reference not set to an instance of an object.
Source=Microsoft.Data.SqlClient
StackTrace:
at Microsoft.Data.SqlClient.SqlDataAdapter.System.Data.IDbDataAdapter.get_SelectCommand()

### To reproduce


```c#
connection = new SqlConnection(GetConnectionStr());

connection.Open(); // error occurs testing any property in Immediate window, so I think the error is here.

string SQL = string.Format("select * from {0}", tableName);
SqlCommand cmd = new SqlCommand(SQL, connection);
 cmd.CommandType = CommandType.Text;
DataTable retn = new DataTable();
SqlDataAdapter adapter = new SqlDataAdapter(cmd);
adapter.Fill(retn);

Expected behavior

It should fill the DataTable as it performed many times before.

Further technical details

Microsoft.Data.SqlClient version: 6.1.3
.NET target: NET 6.0, DotNetCoreApp 6.0.36, AspNetCore 6.0.36
SQL Server version: 13.0.7070.4
Operating system: Windows 11

Additional context
Add any other context about the problem here.

[cheenamalhotra]

@rngkushner

.NET 6 is out of support and is not supported by this driver version. Review MDS 6.1 release notes for supported .NET target frameworks.

Please try with an older driver version that did support .NET 6 at the time of release, e.g. 5.2.x or 5.1.x.

Please note SqlClient version support lifecycle for your awareness as well.