<connectionStrings>
    <add name="PostgreConnectionStringPCMRead"
               connectionString="Server=xxx.xxx.xxx.xxx;Port=5432;User
               Id=the_user;Password=the_password;Database=example;
               CommandTimeout=600;Timeout=30;ConnectionLifeTime=30;
               Pooling=False;"/>
</connectionStrings>

Public Class dlNpgSQL
    Dim _sqlCommand As NpgsqlCommand
    Dim _sqlDataAdapter As NpgsqlDataAdapter
    Dim _dataset As DataSet

    Public Sub New()
        _sqlConnection = New NpgsqlConnection(ConfigurationManager.
                         ConnectionStrings("connstring").ConnectionString)
    End Sub

    Public Function GetDataSet(ByVal strQuery As String) As DataSet
        _dataset = New DataSet
        _sqlDataAdapter = New NpgsqlDataAdapter(strQuery, OpenConnection)
        _sqlDataAdapter.Fill(_dataset)
    End Function

    Public Function GetDataSet(ByVal strQuery As String) As DataSet
        _dataset = New DataSet
        If _sqlConnection.State = ConnectionState.Closed Then
           _sqlConnection.Open()
        End If
    End Function

    Public Sub CloseConnection()
       If _sqlConnection.State = ConnectionState.Open Then
            _sqlConnection.Close()
       End If
    End Function
End Class

Dim ds As DataSet
Dim objDBRead As New dlNpgSQL("connstring")
tmpSQL = "SELECT * FROM table1"
ds = objDBRead.GetDataSet(tmpSQL)
If (objDBRead IsNot Nothing) Then
    objDBRead.CloseConnection()
End If