Shows connection is closed even if connection.open is present - Works when I remove Try Block - sql

Question

This is the function to access the database; the connection string is perfect - There is another Function similar to this and it works fine.
Friend Shared Function AddMember(member As Object) As Task(Of Integer)
Dim connection = New SqlConnection(Configuration.ConfigurationManager.ConnectionStrings("Carrel").ConnectionString)
Dim query = New SqlCommand("INSERT INTO JSON (CATEGORY,DATA) VALUES ('MEM',#JSONString)", connection)
Try
Connection.Open()
query.Parameters.Add(New SqlParameter("#JSONString", JsonConvert.SerializeObject(member)))
Return query.ExecuteNonQueryAsync()
Catch ex As Exception
MsgBox(ex.ToString())
Throw
Finally
query.Connection.Close()
End Try
End Function

Answer 1

Try this:
Friend Shared Async Function AddMember(member As Object) As Task(Of Integer)
Dim cn AS New SqlConnection(Configuration.ConfigurationManager.ConnectionStrings("Carrel").ConnectionString)
Dim query As New SqlCommand("INSERT INTO JSON (CATEGORY,DATA) VALUES ('MEM',#JSONString)", cn)
Try
cn.Open()
query.Parameters.Add(New SqlParameter("#JSONString", JsonConvert.SerializeObject(member)))
Return Await query.ExecuteNonQueryAsync()
Catch ex As Exception
MsgBox(ex.ToString())
Throw
Finally
query.Connection.Close()
End Try
End Function
This should prevent the method from continuing past the ExecuteNonQueryAsync() line until the task returns, so the connection will stay open, but can still run without blocking.
It's also better practice to put the connection and command object in Using blocks, and to not worry about exceptions at this level. This is a data access method... separate that from your presentation code. Let the exception bubble up in the calling code, especially in an Async method:
Friend Shared Async Function AddMember(member As Object) As Task(Of Integer)
Using cn AS New SqlConnection(Configuration.ConfigurationManager.ConnectionStrings("Carrel").ConnectionString), _
cmd As New SqlCommand("INSERT INTO JSON (CATEGORY,DATA) VALUES ('MEM',#JSONString)", cn)
query.Parameters.Add(New SqlParameter("#JSONString", JsonConvert.SerializeObject(member)))
cn.Open()
Return Await query.ExecuteNonQueryAsync()
End Using
End Function
Just be careful, because the async code could be hiding exceptions from you now.

Answer 2

The problem is that, as Aman Bachas said, you're calling ExecuteNonQueryAsync which will start the operation in the background. But then your Finally block will execute and close the connection before the execute actually happens.
What you'll need to do is call the non-Async version but then do your own Async so you can close the connection after it's done.
Public Function AddMember(member As Object) As Threading.Tasks.Task(Of Integer)
Dim connection = New SqlConnection(Configuration.ConfigurationManager.ConnectionStrings("Carrel").ConnectionString)
Dim query = New SqlCommand("INSERT INTO JSON (CATEGORY,DATA) VALUES ('MEM',#JSONString)", connection)
Try
connection.Open()
query.Parameters.Add(New SqlParameter("#JSONString", JsonConvert.SerializeObject(member)))
Return Threading.Tasks.Task.Factory.StartNew(Of Integer)(Function()
Dim ret = query.ExecuteNonQuery()
connection.Close()
Return ret
End Function)
Catch ex As Exception
MsgBox(ex.ToString())
Throw
End Try
End Function
You'll probably want to add some error handling inside the task and clean this up a bit, but that should give you a starting point.

Answer 3

Please replace ExecuteNonQueryAsync() with the ExecuteNonQuery().