Install/Use NpgSQL on Visual Studio 2010 - postgresql

Question

I'm trying to connect to a Postgres 9.5 database using VB.NET/VS2010. I've got the 4.5 .NET framework installed and the project is targeting ".NET Framework 4". I used Npgsql-3.2.5.msi to install the NpgSQL.dll and referenced the dll, but was unable to build the project, or see any of the NpgSQL objects in the intellisense. I had tried using NuGet for the current version, but it threw errors when i tried to install it. I used
"Install-Package Npgsql -Version 3.2.5"
I did some research and was able to install the NuGet Legacy package
"Install-Package Npgsql.EntityFrameworkLegacy -Version 2.2.7"
but the project still refuses to build and I'm still unable to access the Npgsql objects, at least in the intellisense. When I try to build I get
"Could not load file or assembly 'PostGreSQL Test.exe' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded." as an error.
Any help in getting a version of Npgsql to work with Visual Studio 2010 would be greatly appreciated! or at least let me know if it's not possible. This will be a read only connection.
here's the chunk of sample code i'm starting with:
Private Sub GetData()
Using conn = New Npgsql.NpgsqlConnection(connectionString)
conn.Open()
' Retrieve all rows
Using cmd = New Npgsql.NpgsqlCommand("SELECT some_field FROM data", conn)
Using reader = cmd.ExecuteReader()
While reader.Read()
Console.WriteLine(reader.GetString(0))
End While
End Using 'reader
End Using 'cmd
End Using 'conn
End Sub