title: Unable to prevent gridview from refreshing when dropdownlist is selected
body: <p>I have a gridview filled with data under the page_load. This gridview is sortable by alphabet and has a paging ability. However, after selecting a dropdownlist value, the sorted information of my gridview reset to the default page_load data.</p>
  
  <p>I added update panel and trigger but it still doesn't work. I searched all of the SO thread and all advises the trigger and the update panel. I also enable the auto post back in the dropdownlist. The ID of the ddl is also correct. </p>
  
  <pre><code>&lt;asp:UpdatePanel ID="UpdatePanel1" runat="server" &gt;
  &lt;ContentTemplate&gt;
  
        **GridView**      
  
      *dropdownlist category*
      *search textbox*
      *search button*
  
  
  &lt;/ContentTemplate&gt;
  &lt;Triggers&gt; 
  &lt;asp:AsyncPostBackTrigger ControlID="ddlCategory" EventName="SelectedIndexChanged" /&gt; 
  &lt;/Triggers&gt; 
  &lt;/asp:UpdatePanel&gt;
  
  &lt;/asp:Content&gt;
  </code></pre>
  
  <p>How do i exactly prevent the selection of the ddl value from making my sorted ddl's value from resetting to the default data found in page_load. </p>
  
  <p>This is how i bind my gridview in the page_load</p>
  
  <pre><code>Session["gridview"] = DataBindByDataSet();
  
  GVPolice.DataSource = Session["gridview"];
  GVPolice.DataBind();
  </code></pre>
  
  <p>This is the datatable method</p>
  
  <pre><code>private DataTable DataBindByDataSet()
      {
  
          SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);
  
                  conn.Open();
  
                  DataSet ds = new DataSet();
  
                  SqlDataAdapter da = new SqlDataAdapter(*sql command*);
                  da.Fill(ds);
  
                  conn.Close();
  
                   return ds.Tables[0];               
  
     }
  </code></pre>