ASP.net Page pageload called in postback with IsPost back = false - asp.net

Question

Hi everyone i have a strange problem which I hope u can help me with,
i have a normal Asp.net page in which i handle some state data in the page load like this
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
Session["TempD"] = null;
Session["Totals"] = null;
//Handling Sessions here...
}
}
the problem is at a button post back the page_load gets called twice once with IsPostBack
= true which is ok , the second time however IsPostBack = false!!! which cause my code to enter the if condition and reset the state information which is not ok, i use some Ajax Toolkit controls in the page no update panels just some calenders and AutoCompletes.
here is the code for the button causing the post back
protected void TSBtnAddItem_Click(object sender, EventArgs e)
{
if (Session["TempD"] != null)
{
DataLayer.Invoicing.CInvoiceDetail InvoDetails = (DataLayer.Invoicing.CInvoiceDetail)Session["TempD"];
DataLayer.Invoicing.CVarInvoiceDetail var = new DataLayer.Invoicing.CVarInvoiceDetail();
if (LblCurrencyValue.Visible)
{
var.CurencyID = int.Parse(LblCurrencyValue.ToolTip);
}
else
{
var.CurencyID = int.Parse(CboCurrencyValue.SelectedValue);
}
var.ID = 0;
var.InvoiceHeaderID = Convert.ToInt64(InvoiceHeaderID.Value);
var.IsChanges = true;
var.IsFreightItem = false;
var.IsOption = true;
var.ItemAmount = decimal.Parse(txtItemVal.Text);
var.ItemName = CboItemName.SelectedItem.Text;
var.ItemID = int.Parse(CboItemName.SelectedValue);
var.Remarks = "";
if (IsPartLoad.Checked == true)
{
ShipLink.Publics.ApplicationMethods.Item32 itm = LstCalcType.Find(delegate(ShipLink.Publics.ApplicationMethods.Item32 p1) { return Convert.ToInt32(p1.Name.Trim()) == var.ItemID; });
if (itm == null)
{
ADDToCalcList(Convert.ToString(var.ItemID));
if (NumUpDownPortRatio.Enabled == false)
var.ItemAmount = ChangeAmount(var.ItemID, var.ItemAmount);
}
}
InvoDetails.lstCVarInvoiceDetail.Add(var);
Session["TempD"] = InvoDetails;
UGrdInvoiceDetailGrid.DataSource = InvoDetails.lstCVarInvoiceDetail;
UGrdInvoiceDetailGrid.DataBind();
CalcSalesTax();
CalcDiscount();
AddCaseUGrdInvoiceTotalGrid();
}
}

Answer 1

Have a look at this: What is the difference between Page.IsPostBack and Page.IsCallBack?
Integrate if (!IsCallBack) and you should be fine.

Answer 2

I found a solution for this. If you have an global.asax in the project, you need add a new route with "" in a url alias. An example:
private void Generteroutes(RouteCollection routes) {
routes.MapPageRoute("home", "", "~/Default.aspx");
}
load this in Application_Start and problem solved.