How to call Sql function from asp.net code behind

In this article I'm going to explain how to call function from code behind file. User Defined function can be accept both input and return
parameters. These can be called from Asp.net code behind file in this example. Function and Store procedure as same but function return value
but stored procedure may or may not return value. Function are database object in sql server it contains collection of sql statements.

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Net.Mail;
using System.Net;
using System.Data.SqlClient;


public partial class _Default : System.Web.UI.Page 
{

    protected void Page_Load(object sender, EventArgs e)
    {
        try
        {
            SqlConnection con = new SqlConnection("server=pc;uid=sa;password=p@s;database=databasename");

            SqlCommand sqlcmd = new SqlCommand("select dbo.[AddionofTwoNumbers](@Number1, @Number2,@Number3)", con);
            sqlcmd.CommandType = CommandType.Text;
            sqlcmd.Parameters.AddWithValue("@Number1", 10);
            sqlcmd.Parameters.AddWithValue("@Number2", 20);
            sqlcmd.Parameters.AddWithValue("@Number3", 30);
            DataSet dsResutl = new DataSet();
            string stroutput = string.Empty;
            con.Open();
            stroutput =Convert.ToString((Int32)sqlcmd.ExecuteScalar());
            Response.Write(stroutput);
            con.Close();


        }
        catch (Exception ex)
        {
            Response.Write("<script language='javascript'>alert('"+ex.Message.ToString()+"');</script>");
        }
    }
}





CREATE FUNCTION [dbo].[AddionofTwoNumbers]

(

       @Number1 int,
       @Number2 int,
       @Number3 int

)

RETURNS int

AS

BEGIN

       -- Declare the return variable here

       DECLARE @Output int

       SELECT @Output = @Number1 + @Number2+ @Number3;

       -- Return the result of the function

       RETURN @Output

END

Select dbo.[AddionofTwoNumbers](1,2,3)