We are basically sending html to display a GIF through the page_PreInit event as:
Protected Sub Page_PreInit(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.PreInit
Response.AddHeader("Refresh", Convert.ToString((Session.Timeout * 60) + 5))
HttpContext.Current.Response.Buffer = True
HttpContext.Current.Response.Write("<!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.1//EN http://www.w3.org/tr/xhtml11/dtd/xhtml11.dtd'>")
HttpContext.Current.Response.Write("<html xmlns='http://www.w3.org/1999/xhtml'>")
HttpContext.Current.Response.Write("<div ID='divsplashScreen' runat='server'><table cellspacing='0' cellpadding='0' border='0' align='center'><tr><td class='copy' align='right' height='1'></td></tr><tr><td class='copyblack' style='font-family:tahoma;font-size:11px' align='center'><img src='images/progress.gif' border='0' align='absmiddle'><br></td></tr></table></div>")
HttpContext.Current.Response.Write("</body></html>")
HttpContext.Current.Response.Flush()
End Sub
For the most part this approach causes no problems. However with using the ItemsRequested() event for a ListBox on a page using this technique it fails. the ItemRequested() event fires and does not generate an error although the list box is not being populated by the this event. I am assuming that this is happening because the document is not well formed. Basically sending anything to the document prior to the DOCTYPE causing the event to fail.
Can anyone think of a way around this?
Robert
5 Answers, 1 is accepted
RadListtBox does not provide event named ItemsRequested. How exactly are you binding the listbox?
Greetings,
Genady Sergeev
the Telerik team
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This is adapted from the online demo.
the one listbox is calling client function to load the other listbox.
OnClientSelectedIndexChanging
="LoadSteps"
function LoadSteps(combo, eventArqs)
{
var item = eventArqs.get_item();
var cboSteps = $find("<%=cboCurrentStep.ClientID%>");
cboSteps.set_text(
"Loading...");
// steps combobox passing pub cycle as parameter
cboSteps.requestItems(item.get_value(),
false);
cboSteps.set_text(
" All");
}
Protected Sub cboCurrentStep_ItemsRequested(ByVal o As Object, ByVal e As Telerik.Web.UI.RadComboBoxItemsRequestedEventArgs) Handles cboCurrentStep.ItemsRequested
LoadSteps(e.Text)
End Sub
Protected Sub LoadSteps(ByVal sCycle As String)
Dim conn As New SqlConnection(ConfigurationManager.ConnectionStrings("RTS_ConnectionString").ConnectionString)
Dim Sql As String = " select anc.name as step, anp.name as parent "
Sql += " ,ap.sequence_order, ac.sequence_order "
Sql += " from activities ap, "
Sql += " activities ac, "
Sql += " lookups lu, "
Sql += " activity_names anc, "
Sql += " activity_names anp "
Sql += " where ac.type_id = lu.lookup_id "
Sql += " and ac.name_id = anc.activity_name_id "
Sql += " and ac.parent_id = ap.activity_id "
Sql += " and ap.name_id = anp.activity_name_id "
Sql += " and lu.name = 'Step Template' "
Sql += " and anp.name=@sched "
Sql += " UNION SELECT ' All' as step, '' as parent,0,0 "
Sql += " order by ap.sequence_order, ac.sequence_order "
Dim adapter As New SqlDataAdapter(Sql, conn)
adapter.SelectCommand.Parameters.AddWithValue("@sched", sCycle)
Dim dt As New DataTable()
adapter.Fill(dt)
cboCurrentStep.DataTextField = "Step"
cboCurrentStep.DataValueField = "Step"
cboCurrentStep.DataSource = dt
cboCurrentStep.DataBind()
End Sub
Rank 1
When a RadComboBox requests its items, it invokes the page using a callback. Therefore, the Page property IsCallback is true. I suggest that you check for this property to be false before flushing the text into the browser. I have also noticed that in your LoadSteps method you use += to concatenate strings. However, this construction does not work in VB.NET and will produce a compile error. I suggest that you use the StringBuilder class to concatenate strings. It is faster and more reliable than simple &ing the strings.
Best wishes,
Genady Sergeev
the Telerik team
Instantly find answers to your questions on the new Telerik Support Portal.
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R