using Execute Scalar with a Data Adapter

Hi Everyone!
I have written a DataAccessLayer (DAL) and it works great for filling DataTables and DataSets.  Today I am attempting to add three new methods: ExecuteScalar, ExecuteReader and ExecuteNonQuery.  My DAL has a constructor, add parameters method, clear parameters method, ExecuDataSet method, and ExecTable method.  I think it needs ExecuteScalar, ExecuteReader and ExecuteNonQuery methods too!  Here it is below.
You can see it uses a data adapter and stored procedures.  How can I continue to use a data adapter, and add ExecuteScalar, ExecuteReader and ExecuteNonQuery ?????
Imports Microsoft.VisualBasic Imports System.Data Imports System.Data.DataRow Imports System.Data.DataTable Imports System.Data.SqlClient Public Class DAL Dim con As SqlConnection Dim cmd As SqlCommand() Dim da As SqlDataAdapter Public Sub New(ByVal conString As String) 'Se ...