ASP.NET

protected void Page_Load(object sender, EventArgs e)
{
   if(!IsPostBack)
    {
       FillConatcsGrid();//fills you contacts datagrid only once
       CheckSessionId();//Will check the session id if need be only once
       //Then you can go ahead with more fun in here...
    }
}

protected void DateFrom_SelectedIndexChanged(object sender, EventArgs e)
{
   calDateFrom.Visible = true;
   this.DateFrom.Text = calDateFrom.SelectedDate.ToString();
}

MorgSim wrote:

protected void DateFrom_SelectedIndexChanged(object sender, EventArgs e)

<script type="text/javascript" language="javascript">
function ShowHideCalendar() {
            var obj = document.getElementById('yourCalendarId');
            if (obj.style.display == 'block') {
                obj.style.display = 'none';
            }
            else {
                obj.style.display = 'block';
            }
        }
    </script>

<asp:DropDownList runat="server" ID="ddlMyDropDown" onmousover="ShowHideCalendar();">
        <asp:ListItem Value="1">item 1</asp:ListItem>
        <asp:ListItem Value="2">item 2</asp:ListItem>
    </asp:DropDownList>