Best Practice code and issues
<p>I am a beginner and writing code to display data in a Gridview using Asp.Net and c#. I want to know if the approach I followed is correct or not. I want suggestions on standards and architectural issues, best practices with my code so that I can modify my code accordingly. I appreciate your great suggestions and code additions.</p>

<p><strong>Connection Code:</strong> </p>

<pre><code>    public class DemoProjConnectionClass
    {
        public SqlConnection DemoProjConnection()
        {
            SqlConnection con = new SqlConnection("Data Source=Localhost;Initial Catalog=master;Integrated Security=True");
            return con;
        }
    }
</code></pre>

<p><strong>Domain Code(gets &amp; sets):</strong> </p>

<pre><code>public class DemoProjDomainClass
{

public int EmpId { get; set; } 
public string EmpName { get; set; } 
public int Salary { get; set; } 

 } 
</code></pre>

<p><strong>Class Library Code:</strong> </p>

<pre><code>public class DemoProjServiceClass
{
    public IList&lt;DemoProjDomainClass&gt; getDemoProjList()
    {
        string sqlDemoProjList;
        sqlDemoProjList = "SELECT EmpId,EmpName,Salary from Employee";
        DemoProjConnectionClass x = new DemoProjConnectionClass();
        SqlConnection con = x.DemoProjConnection();
        con.Open();
        SqlCommand cmd = new SqlCommand(sqlDemoProjList, con);
        cmd.CommandType = CommandType.Text;
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds, "tempTable1");



        IList&lt;DemoProjDomainClass&gt; DemoProjList = new List&lt;DemoProjDomainClass&gt;();
        for (int i = 0; i &lt; ds.Tables[0].Rows.Count; i++)
        {
            DemoProjDomainClass _obj = new DemoProjDomainClass();

            _obj.EmpId = Convert.ToInt16(ds.Tables[0].Rows[i][0]);_obj.EmpName = ds.Tables[0].Rows[i][1].ToString();_obj.Salary = Convert.ToInt16(ds.Tables[0].Rows[i][2]);DemoProjList.Add(_obj);
        }
        return DemoProjList;
    }
} 
</code></pre>

<p><strong>UI Code</strong></p>

<pre><code>protected void Page_Load(object sender, EventArgs e)
{
   DemoProjServiceClass ob=new DemoProjServiceClass();
    GridView1.DataSource = ob.getDemoProjList();
    GridView1.DataBind();

}
</code></pre>
