SqlConnection object not recognized

Not sure why this is happening. I'm using the correct library "System.Data.SqlClient". Please see below image. If image is to small to see, how can I enlarge it? Thanks!Attachment 188456

What framework are you targeting? I'm guessing it's some version of .NET Core, including .NET 5 or later. When you target .NET Framework, there is generally a reference to System.Data.dll added by default and that contains the System.Data.SqlClient provider. When you target .NET Core, each ADO.NET provider is in its own library and none are referenced by default, so you need to install the appropriate NuGet package. You can use System.Data.SqlClient but it exists basically for backward compatibility. Instead, you should install the Microsoft.Data.SqlClient package, as that's where all the new development is being done. The types and members that you're used to will still be there. You just need a different namespace import.

Thank you sir...