Error here System.ArgumentOutOfRangeException: 'ddl_hotel' has a SelectedValue which is invalid because it does not exist in the list of items. Parameter name: value at System.Web.UI.WebControls.ListControl.PerformDataBinding(IEnumerable dataSource) at System.Web.UI.WebControls.ListControl.OnDataBinding(EventArgs e) at System.Web.UI.WebControls.ListControl.PerformSelect() at System.Web.UI.WebControls.BaseDataBoundControl.DataBind() at MasterPage.Page_Load(Object sender, EventArgs e) in C:\inetpub\wwwroot\HGC\MasterPage.master.vb:line 66