Question

I’ve a Calendar on my webpage, and during the page_load event I’m setting the webpage to take today’s date and load the data for today’s date in the Gridview. Paging is allowed in the Gridview.

I also have a Calendar_Selectiondate event and when someone clicks on a date in the calendar, it will show data for that date. The date value is showed in a session variable. In this scenario when I click on the paging hyperlink 2, it will take me to the current day’s second page instead of the selected day’s second page. I know this is because it’s going through the Page_Load event whenever I click on that hyperlink 2 and the date is getting set to Today’s date instead of the selected date.

public partial class UKMail_UKMail7Day : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Calendar.SelectedDate = DateTime.Today;
        Session["MailDate"] = Calendar.SelectedDate;
        UKMail7DayGridView.DataSourceID = "UKMail7DaySelected";
        UKMail7DayGridView.DataBind();
        //UKMail7DayGridView.DataSourceID = "UKMail7DayAllData";
        //UKMail7DayGridView.DataBind();
    }
    protected void Calendar_SelectionChanged(object sender, EventArgs e)
    {
        Session["MailDate"] = Calendar.SelectedDate;
        UKMail7DayGridView.DataSourceID = "UKMail7DaySelected";
        UKMail7DayGridView.DataBind();
    }
}

Answer 1

The events in your Page_Load execute no matter what triggers the postback. If you have code that should ONLY happen the FIRST time a page is loaded, put it within an if(!Page.IsPostback) block.

void Page_Load(object sender, EventArgs e)
{

   // code that will execute on every postback, button click, etc.
   if(!Page.IsPostback)
   {
      //code that will only execute the first time the page is  loaded.
   }

}

Strongly recommended reading: (Every ASP.NET developer should know this.) http://msdn.microsoft.com/en-us/library/ms178472.aspx

Edit using your updated code:

public partial class UKMail_UKMail7Day : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if(!Page.IsPostback)
        {
          Calendar.SelectedDate = DateTime.Today;
          Session["MailDate"] = Calendar.SelectedDate;
          UKMail7DayGridView.DataSourceID = "UKMail7DaySelected";
          UKMail7DayGridView.DataBind();
          //UKMail7DayGridView.DataSourceID = "UKMail7DayAllData";
          //UKMail7DayGridView.DataBind();
        }
    }
    protected void Calendar_SelectionChanged(object sender, EventArgs e)
    {
        Session["MailDate"] = Calendar.SelectedDate;
        UKMail7DayGridView.DataSourceID = "UKMail7DaySelected";
        UKMail7DayGridView.DataBind();
    }
}