SocketException thrown when using linq for Npgsql EntityFramework6 model - entity-framework

Question

After much effort getting my MVC5 vb.net app configured with Npgsql and EntityFramework6.Npgsql I can connect to the postgres database fine using the Entity Data Model Wizard in Visual Studio 2017, creating a new connection with Data Provider of PostgreSQL Database, entering my database server details and testing the connection (succeeds). I can also double-click the EDMX file and add tables, etc as expected. This is my first project that talks to a postgreSQL database (normally use MS SQL Server). Everything seems to be happy and fine until I encounter code that is a linq statement that attempts to query the database. My Linq statement is:
Dim l_ListOfPwrCycleCrashEvents As List(Of pwr_cycle_crash_events) = (From item In m_AnalyticsEntities.pwr_cycle_crash_events Where item.serialnumber = "0123445678" Select item).ToList
I have the statement in a try/catch block, but visual studio still reports the following:
Exception thrown:'System.Net.Sockets.SocketException' in System.dll Additional
information: A non-blocking socket operation could not be completed
immediately occurred
I cannot seem to figure out why this statement fails. I am able to use similar statements against a different EntityFramework (MS SQL Server) that is also configured in the application.
The complete method that contains the linq statement:
Public ReadOnly Property iCountOfPwrCycleCrashEvents(
ByVal a_sSerialNumber As String
) As Integer Implements IAnalytics.iCountOfPwrCycleCrashEvents
Get
Try
Dim l_ListOfPwrCycleCrashEvents As List(Of pwr_cycle_crash_events) = (From item In m_AnalyticsEntities.pwr_cycle_crash_events
Where item.serialnumber = a_sSerialNumber
Select item).ToList
If (l_ListOfPwrCycleCrashEvents IsNot Nothing) Then Return l_ListOfPwrCycleCrashEvents.Count
Catch l_Exception2 As System.Net.Sockets.SocketException
Dim askjfhakjh As Integer = 7
Catch l_Exception As Exception
Dim kjhadkjh As Integer = 1
End Try
Return 0
End Get
End Property
I am using Npgsql v4.1.1 and EntityFramework6.Npgsql v6.3.0 in an application that targets .NET Framework 4.5.1.
I can't seem to figure out why the linq statement throws this exception or how to solve the problem. What suggestions do you have?

Answer 1

I figured out the issue. I was using 4.5.1 framework because I thought I had a dependency that would not allow me to move to 4.5.2. I went to Package Manager Console and ran the following command:
Update-Package -ProjectName myProjectName -reinstall
By doing so, I found that I had a package that was needed but could not be loaded because it required the 4.5.2 framework (or higher). I changed the framework of the app to 4.5.2 and issued the above Package Manager command and it executed without errors. I ran the app and the linq statement no longer throws an exception.