check compiler with break point
<p>When I tried to focus on compiler in code, I made break point on code.</p>

<pre><code>if (!IsPostBack)
{
    using (SqlConnection Con = Connection.GetConnection())
    {
        if (Request.QueryString["Category_Id"] != null &amp;&amp;
            DDlProductFamily.SelectedIndex &lt; 0)
        {
            SqlCommand Com = new SqlCommand("SelectAllCtageories_Front", Con);
            Com.CommandType = CommandType.StoredProcedure;
            Com.Parameters.Add(Parameter.NewInt(
                "@Category_Id", Request.QueryString["Category_Id"]));

            SqlDataAdapter DA = new SqlDataAdapter(Com);
            DA.Fill(dt);
            DataList1.DataSource = dt;
            DataList1.DataBind();
        }
</code></pre>

<p>But I cannot check condition although I had the value of query string.</p>
