Link Button as trigger not firing

So I have a link button that is created here...

 LinkButton hide =new LinkButton(); hide.Text ="(hide)"; hide.Click +=new EventHandler(this.hide_Click); hide.ID ="hide" + deviceID;

which is later added to a table cell which is added to a table row which is added to a table. This table is what my function returns (the functions basically builds the table)

From where the function is called I have this code to create a trigger using the linkbutton hide, then add that trigger to the update panel that i am putting the newley created table in...

 AsyncPostBackTrigger trig =new AsyncPostBackTrigger(); ((UpdatePanel)tempTable.Parent.Parent).ContentTemplateContainer.Controls.Add(childTable); trig.ControlID = childTable.Rows[0].Cells[1].Controls[1].UniqueID; trig.EventName ="Click"; ((UpdatePanel)childTable.Parent.Parent).Triggers.Add(trig);

I have tried making the controlID both the unique ID and just the ID and neither work. I know that my just for testing my hide_click function is simple...

private void hide_Click(object sender, EventArgs e) { txtOutput.Text ="IT WORKED!"; }

I know the hide_Click function works because i attached it to other buttons in other tables and it executes fine.

Does anyone know if I am doing something wrong because I cannot seem to figure this out.

Thanks

Hi,

what issue are you experiencing? A full postback instead of an async postback? Or the "IT WORKED!" text isn't displayed? In this case, did you put the Label inside an UpdatePanel?

There is no postback at all. The txtOuput is inside an update panel. It works fine when triggered from other buttons that were added to my page the same way I am adding my link button, but something is acting up. Im not sure if there is a problem with where I am adding the trigger so I am going to try defining the trigger at the same place in code as where I am defining the link button to see if that helps, but i doubt that will change anything.

Ok this is really starting to mess with my head. I have noticed now that when i click on my button, the textbox txtOutput refreshes, but still displays the text that was already there, instead of getting the text from the hide_Click function. This is weird though because when I point other buttons to my hide_Click function, they fire it perfectly and the text box updates. I am confussed

Hi,

Please refer to this:

http://ajax.asp.net/docs/mref/T_System_Web_UI_AsyncPostBackTrigger.aspx

Programmatically adding AsyncPostBackTrigger controls is not supported. Use the RegisterAsyncPostBackControl(Control) method of the ScriptManager control to programmatically register a postback control, and then call the Update() method of the UpdatePanel when the control posts back.

Please try as the above documentation described. If still fails, please post a self-sufficient repro.

great thanks, ill take a look. I was all excited because I was able to programatically add asyncpostback trigers to some update panels, I did this at the time the panels were being created and it worked fine, I guess there are some situations where it just doesnt work though.

so it turns out the trigger is working fine, the only problem is that my hide_Click event isnt being fired. I have had this problem before where having certain settings enabled for different controls cause the controls .click event not to work properly, now its just a matter of finding out what is causing this problem

link button inside update panel causes post back

I have a linkbutton inside the update panel. I registered it with AsyncPostBackTrigger, but when I click that link button, the whole page is refreshed instead of that update panel, what could I have gone wrong?

Check the EnablePartialRendering="true" of ScriptManager is et or not ?

Also check UpdateMode="Conditional" of UpdatePanel is set or not ?

link buttons in user control not recognised by updatePanel

Hello...

I have a usercontol that has some linkbuttons.....and an updatePanel...i put the linkbutton ID's in the Trigger section of the updatePanel, but I'm getting an error that the updatePanel does not recognise the button ID's I have passed in...

how do I fix this? thanks

Hi,

Update Panel is not gonna recognize those link buttons because they are inside of usercontrol. You need to create user control event for each link button event. For example,

CustomControl.ascx

<%@. Control Language="C#" AutoEventWireup="true" CodeFile="CustomControl.ascx.cs" Inherits="CustomControl" %>
<asp:LinkButton ID="lnkTest" runat="server" OnClick="lnkTest_Click">Test Button</asp:LinkButton

CustomControl.ascx.cs

public partial class CustomControl : System.Web.UI.UserControl
{
public delegate void TestHandler(object sender, EventArgs e);
public event TestHandler LinkClicked;

protected void Page_Load(object sender, EventArgs e)
{

}
protected void lnkTest_Click(object sender, EventArgs e)
{
if (LinkClicked != null)
LinkClicked(this, new EventArgs());
}
}

test.aspx

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="CustomControl1" EventName="DoYourBussiness" />
</Triggers>
<ContentTemplate>
<uc1:CustomControl ID="CustomControl1" runat="server" OnLinkClicked="DoYourBussiness" />
</ContentTemplate>
</asp:UpdatePanel

Hi,

thanks for this, how about for normal hyperlinks?... (instead of linkButons)... can something similar be done?

thanks

Hi,

Normal hyperlinks do not have OnClick event. LinkButton looks the same as HyperLink, but has OnClick event.

Link Click refresh effect?

I got a master page and 2 content page.

the menu links are on the left content page.

How can i get refresh effect on the right content page when i click on the links on the left page?

http://code.google.com/webtoolkit/documentation/examples/kitchensink/demo.htmlHi,

one approach is to use theUpdatePaneltogether with theMultiViewcontrol.
Thanks very much,i got it.
sorry, can i get that kind of effect just click a link on the page without MultView?

eg. i put a link on the left content page. the right content page will refresh when i click the link?

Hi Joytony,

When you click the link, do you want to display a totally new page?? could you post the code you use for the links?

Greetings,

Dennis

Thanks Dennis,

This is the demo i did.

1 master page contain 2 links on it.
while i have 2 content page

~/Default2.aspx
~/Default3.aspx

How can i get the refresh effect in this model?

<%@. Master Language="C#" AutoEventWireup="true" CodeFile="MasterPage.master.cs" Inherits="MasterPage" %>"-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml">Untitled Page"server"> "form1" runat="server"> "scriptmanager1" EnablePartialRendering="true" runat="Server" /> "up1" runat="server">
 "HyperLink1" runat="server" NavigateUrl="~/Default2.aspx">HyperLink "HyperLink2" runat="server" NavigateUrl="~/Default3.aspx">HyperLink
 "ContentPlaceHolder1" runat="server">
 "Progress" runat="server"> Loading...

sorry, put the code again.

<form id="form1" runat="server"> <atlas:ScriptManager ID="scriptmanager1" EnablePartialRendering="true" runat="Server" /> <atlas:UpdatePanel ID="up1" runat="server"> <ContentTemplate> <div> <asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl="~/Default2.aspx">HyperLink</asp:HyperLink> <asp:HyperLink ID="HyperLink2" runat="server" NavigateUrl="~/Default3.aspx">HyperLink</asp:HyperLink> <asp:LinkButton ID="LinkButton1" runat="server">LinkButton</asp:LinkButton> <asp:LinkButton ID="LinkButton2" runat="server">LinkButton</asp:LinkButton> </div> <div> <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server"> </asp:ContentPlaceHolder> </div> </ContentTemplate> </atlas:UpdatePanel> <atlas:UpdateProgress ID="Progress" runat="server"> <ProgressTemplate> Loading... </ProgressTemplate> </atlas:UpdateProgress> </form>

Hi JoyTony,

I don't think that its possible to open a new page in another frame without a full postback. (If this is want you want to achieve). I think that Atlas is useful when you want parts of a webpage to be updated not whole pages. I think that the suggestion above with the multiview is the only option. Is there a reason that you don't want to use multiview??

Greetings,

Dennis

Hi Again,

What is the reason that you put your buttons in the update panel? These controls shoudn't be updated right?

Regards

Hmm, it seems you're kinda misusing the concept., although I do see what you're trying to do i think. If I'm not mistaken you're trying to only get the non master portion to refresh, similar to what one would achieve using frames? If so, other than the fact that it's probably not going to work, your pages will not be picked up by search engines, which is really bad unless its an intranet site.

It would be real nice if ATLAS did solve the problem of same masterpage markup being sent back with every page though, but i guess with a well designed site that should be very minimal.

Nick

Thanks Dennis andnicksh.

The reason why i don't want to use multiple view is i've done many pages there.

I just leave it there at the moment untill we really want to change. Thanks.

Link inside a draghandles template

Is it possible to access a link or a textbox inside a draghandle's template?

I want all the controls inside the draghandle to be dragable and also that users could click on these controls inside the draghandle

talking about ReorderList's DragHandle..

I"m trying to do a similar thing. Originally, I wanted to be able to drag any portion of a ReorderItem to a different position. The problem I ran into is that if you don't declare a position for the DragHandle, you can drag from any place on the ReorderItem BUT this means you cannot click on any controls that are contained in the ReorderItem, making them all useless. The control thinks that if you click ANYWHERE, you're trying to drag it, so the controls can never be used.

So, to remedy this problem, I thought to do exactly what you're doing. I added a <DragHandle> to the left side which contains a Label; this Label was to hold the sequence number of the ReorderItems (so the first item would have a 1, the second would contain a 2, etc), but like you I cannot access this control from the code behind when the Reorder event fires.

your problem seems diferent than mine. I don't have any problems accesing controls in the code behind. I'm trying to figure out how to make some parts of the draghandle dragable and some of them "clickable". I guess i need to construct some <div> element consisting of several other <div> elements and put a draghandle inside one of them. But here is another problem: you cannot place the draghandle anywhere you like, just four possitions. So i cannot put it inside a particular <div> element

I guess i need to think another way to do it

link usage by ajax framework

HI, I am new using ajax... so..I created a small project with a few controls inside a page.I was doing well every think fine.So I started a web test project to see the impact of using ajax inside my page (link usage)...and what I see was a use of a "library" off size 250Kb ...Is this correct I doing something wrong ?

The controls that I was testing was part off the toolkit

Hi,

According to my understanding, you noticed a .js file with size of 250 KB was downloaded.

This is the correct behavior. Actually, AJAX is implemented with javascript, which will be responsible for sending request asynchronously, update contents on the web form. And there are also a lot auxiliary methods and objects.

So, it's normal to see this.

Just pay attention to changing the debug mode to false in web.config before you are going to deploy your application.

I would like to know if this .js will be downloaded at each post in the page? For navigation between different pages that use Ajax technology .js will be downloaded several times? What I expected is that .js was to be downloaded only once. But my tests don't show this! Am I correct? Or I am loosing something Thank you Very Much

You need to set debug to false in web.config.

Linked List of Hover Menus

Say I have a hover panel with a bunch of links. When the user hovers over a link, the same hover panel should appear with the same links, and again when the user hovers over a link, the panel appears for the 3rd time, and so on...

For example, say my Panel has Links A, B, C, D, and E. If the user hovers over link B, a panel should appear with the links A, B, C, D, and E. Again, say if the user clicks on link C, the panel appears again with the same links...this way the user can form a linked list of items that were hovered over. For example, B-->C-->A-->D. When the user final clicks on a link (instead of simply hovering), that would signal the end, and a reference to the linked list (B-->C-->A-->D) needs to be posted back to the server.

My questions are:

1. How do I achieve this dynamic hover menu effect?

2. How can I maintain the list of links that were hovered over each panel, so that I can finally postback the set of links hovered over to the server.

I'd appreciate if anyone could help me on this. I am creating a website that needs this functionality.

Thanks!

This sounds like it may get more complicated than you want. I'd look at maybe creating the hover behaviors on the client so that you can handle the arbitrary nesting that results after the user makes a few choices.

Linking two DropDowns via Atlas?

I have looked at the Atlas controls (January 2006 Release)

What i would like to know is, say i make a dropdown, place it in a
update panel, then link it all up to some datasource, add a trigger to
the page to populate the dropdown, e.g. a button (i get this going
np.)

Now what i would like to do is add a second dropdown and have it
update when i make a selection from the first dropdown, this i can not
get to work.

In the Atlas controls smart tag to add the triggers i only get to see
controls on the page which are not located within a updatepanel,

So i tried to just write then trigger manually, this produced no
visible error on the page, but the second dropdown is not populating
either?

Is this along the lines you are looking to do?

<atlas:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true" />

<atlas:UpdatePanel runat="server" ID="UpdatePanel1" Mode="Conditional" >
<ContentTemplate>
<asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" AutoPostBack="True">
<asp:ListItem Text="foo" Value="foo" />
<asp:ListItem Text="bar" Value="bar" />
</asp:DropDownList>
</ContentTemplate>
</atlas:UpdatePanel>
<hr />
<atlas:UpdatePanel runat="server" ID="Computer" Mode="Conditional">
<Triggers>
<atlas:ControlEventTrigger ControlID="DropDownList1" EventName="SelectedIndexChanged" />
</Triggers>
<ContentTemplate>
<asp:DropDownList ID="DropDownList2" runat="server">
</asp:DropDownList>
</ContentTemplate>
</atlas:UpdatePanel>

No thats it exactly, but thank you

Did you have to manually type the second trigger (to populate dropdown2)?

What i was wondering was,

Say you had a button, when pressed, it fired a trigger to populate the first Dropdown1 (Foo, Bar)

Then I wanted to be able to make a selection from the Dropdown1 and then get data to populate Dropdown2,

by running a SQL Query which took the selected item from Dropdown1 as a param.

Made a Typo sorry

I said in last post

No thats it exactly, but thank you

I mean

No thats not exactly it, but thank you

Example, this does not update the second "Dropdown2", both controls are contained in the 1 UpdatePanel

<atlas:UpdatePanel runat="server" ID="UpdatePanel1" Mode="Conditional">
<ContentTemplate>
<asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged"
AutoPostBack="True">
<asp:ListItem Text="foo" Value="foo" />
<asp:ListItem Text="bar" Value="bar" />
</asp:DropDownList>
<asp:DropDownList ID="DropDownList2" runat="server">
</asp:DropDownList>
</ContentTemplate>
<Triggers>
<atlas:ControlEventTrigger ControlID="Button1" EventName="Click" />
<atlas:ControlEventTrigger ControlID="DropDownList1" EventName="SelectedIndexChanged" />
</Triggers>
</atlas:UpdatePanel>

This example does, but you need to have 2 UpdatePanels

<atlas:UpdatePanel runat="server" ID="UpdatePanel1" Mode="Conditional">
<ContentTemplate>
<asp:DropDownList ID="DropDownList1" runat="server" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged"
AutoPostBack="True">
<asp:ListItem Text="foo" Value="foo" />
<asp:ListItem Text="bar" Value="bar" />
</asp:DropDownList>
</ContentTemplate>
<Triggers>
<atlas:ControlEventTrigger ControlID="Button1" EventName="Click" />
</Triggers>
</atlas:UpdatePanel>
<hr />
<atlas:UpdatePanel runat="server" ID="Computer" Mode="Conditional">
<Triggers>
<atlas:ControlEventTrigger ControlID="DropDownList1" EventName="SelectedIndexChanged" />
</Triggers>
<ContentTemplate>
<asp:DropDownList ID="DropDownList2" runat="server">
</asp:DropDownList>
</ContentTemplate>
</atlas:UpdatePanel>

in this example i have the script manager and updateprogress atlas controls on a master page, thus i gane share them around between different pages in the test site this has the button control out site which triggers the population of the dropdown1 control, then making a selection from the dropdown1 populates dropdown2 This is what i wanted to do in the first post i made.

Client side code:

<%@.PageLanguage="VB"MasterPageFile="~/MasterPage.master"AutoEventWireup="false"CodeFile="Default.aspx.vb"Inherits="_Default"title="Untitled Page" %>

<asp:ContentID="Content1"ContentPlaceHolderID="ContentPlaceHolder1"Runat="Server">

<div>

<asp:ButtonID="Button1"runat="server"Text="Button"/>

<atlas:UpdatePanelrunat="server"ID="UpdatePanel1"Mode="Conditional">

<ContentTemplate>

Dropdown 1

<asp:DropDownListID="DropDownList1"runat="server"OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged"

AutoPostBack="True">

<asp:ListItemText="foo"Value="foo"/>

<asp:ListItemText="bar"Value="bar"/>

</asp:DropDownList><br/>

Dropdown 2

<asp:DropDownListID="DropDownList2"runat="server">

</asp:DropDownList>

</ContentTemplate>

<Triggers>

<atlas:ControlEventTriggerControlID="Button1"EventName="Click"/>

<atlas:ControlEventTriggerControlID="DropDownList1"EventName="SelectedIndexChanged"/>

</Triggers>

</atlas:UpdatePanel>

</div>

</asp:Content>

Server Side code:

PartialClass _Default

Inherits System.Web.UI.Page

Dim dsAs Data.DataSet

Dim obsAs Data.DataTable

Dim defAs Data.DataTable

ProtectedSub Page_Load(ByVal senderAsObject,ByVal eAs System.EventArgs)HandlesMe.Load

ds =New Data.DataSet

obs =New Data.DataTable

def =New Data.DataTable

ds.ReadXml("url to my xml datasopurce here")

def = ds.Tables("data-def")

obs = ds.Tables("obs")

EndSub

ProtectedSub DropDownList1_SelectedIndexChanged(ByVal senderAsObject,ByVal eAs System.EventArgs)

Dim xmldocAsNew System.Xml.XmlDocument

xmldoc.LoadXml(ds.GetXml)

Dim obsAs System.Xml.XmlNodeList = xmldoc.SelectNodes("weather-observations/product/group/obs")

Dim xmlEAs System.Xml.XmlElement

ForEach xmlEIn obs

If xmlE.Attributes.Item(4).Value =Me.DropDownList1.SelectedItem.TextThen

Me.DropDownList2.Items.Clear()

Dim xmlEnumeratorAs IEnumerator

xmlEnumerator = xmlE.ChildNodes.GetEnumerator()

xmlEnumerator.Reset()

While xmlEnumerator.MoveNext

Dim eleAs System.Xml.XmlElement

ele = xmlEnumerator.Current

Me.DropDownList2.Items.Add(ele.Attributes.Item(0).Value &" : " & ele.FirstChild.Value)

EndWhile

EndIf

Next

EndSub

ProtectedSub Button1_Click(ByVal senderAsObject,ByVal eAs System.EventArgs)Handles Button1.Click

Me.DropDownList1.DataSource = obs

Me.DropDownList1.DataTextField ="station"

Me.DropDownList1.DataBind()

EndSub

EndClass

In the latest rev of Atlas, controls within the UpdatePanel should not require an explicit trigger as this is implied. If you want the UpdatePanel to refresh based on controls outside the UpdatePanel then the trigger is required. This therefore means that controls outside the UpdatePanel are traditionally post-back controls unless wired to triggers.The simplified example (#1) therefore should be OK without the DropDownList trigger. The Click handler of the button could be used to drive population of drop-down list 1. I'll try and work on a server binding sample for you.

Odd -- I was trying my own code (pretty much the exact code as above) and I get an "Unknown Error". I tried this code, and I get the same error. Its a pretty vague error, but any ideas as to where I should begin to look?

Thanks!

I checked this code ( the good one ) and put one breakpoint at first line in page load method. Every time I changed the option in the DropDownList and the application stopped on the breakpoint.

I don't know if this control (UpdatePanel ) works in this way or is something wrong in the code but I supossed that the panel is updated with an asynchronous server call. Could anybody explain me the functionality of the control?

Thanks.

The Code is Good But Doesnt Work ...

Please help ..

Links for the images in slide show extender

Hai,

I am wondering why there is no way to provide link for the images in the Ajax slide show extender, Is there any way to provide links for the images in slide show extender?

Thanks & Regards

Mahesh

Hi Mahesh,

As far as I know, this feature isn't available now, you may submit a feature requesthere. Thanks.

load page without refresh

at first excuse me if my english is bad

i need load pages without refresh page

for example in page a i click link (page b) now i want load page b without refresh page

You would want to use iframes or have user controls for every page. I have not used either, but saw various posts about doing that. It ends up getting very hacky though so we avoid that.

LoadControlState event not firing in update panel.

I have a link which is wrapped in a update panel. This link works as an expand/collapse link. The expand/collapse status of the link is saved in the control state. But i found that the LoadControlState event does not fire but the SaveControlState does. Because of this, i always get the expand/collapse state of the link as Collapsed which is default. I am kind of stuck on this now. I dont want to use session as it does not sound like a session wide data. I tried using hidden variables but even that does not work with ajax because Request.Form always has old value.

The reason i want to use control state and not viewstate is becasue i want to disable the viewstate on this page.

Any help is much appreciated.

Nilesh

Hi Nilesh,

I tried using hidden variables but even that does not work with ajax because Request.Form always has old value.

What you mean?

If you want to store something,you can store them in javascript variables.

Please check this:http://forums.asp.net/p/1134520/1813803.aspx#1813803

it store the scrollLeft/scrollTop in javascript variables.

Best Regards.

Loading Image Postion

Hello all

i use ajax using XMLHTTPREQUEST object i have function called ajxpg(link,container) take two paramter the link of the destination page and the container where the sestination pae wil be dispalyed and aslo it take a varible witch contain the image page witch will be displayed while the page is loading .

my problem that is this picture is displyed in upper right of the displyed page iwant here to be displyed in the middle of the page that is dispalyed in the continer .

ihope i can found a soulution.

Javascript:

image.style.position = absolute
image.style.top = ((screen.height/2) - (image.height/2))
image.style.left = ((screen.width/2) - (image.width/2))

This the the ajax function witch i put in javascript file named Ajax.js

ar bustcachevar=1 //bust potential caching of external pages after initial request? (1=yes, 0=no)
var loadedobjects=""
var rootdomain="http://"+window.location.hostname
var bustcacheparameter=""

function ajaxpage(url, containerid)
{
var page_request = false
if (window.XMLHttpRequest) // if Mozilla, Safari, Firefox, Opera 8.0+, Safari
page_request = new XMLHttpRequest()
else if (window.ActiveXObject) // ifInternet Explorer\
{
try {
page_request = new ActiveXObject("Msxml2.XMLHTTP")
}
catch (e)
{
try{
page_request = new ActiveXObject("Microsoft.XMLHTTP")
}
catch (e){}
}
}
else
return false

document.getElementById(containerid).innerHTML=loadstatustext
page_request.onreadystatechange=function()
{
loadpage(page_request, containerid)
}
if (bustcachevar) //if bust caching of external page
bustcacheparameter=(url.indexOf("?")!=-1)? "&"+new Date().getTime() : "?"+new Date().getTime()

page_request.open('GET', url+bustcacheparameter, true)
page_request.send(null)

}

function loadpage(page_request, containerid){
if (page_request.readyState != 4)
{return;}
if (page_request.readyState == 4 && (page_request.status==200 || window.location.href.indexOf("http")==-1))
document.getElementById(containerid).innerHTML=page_request.responseText
//alert(page_request.responseText)
}

and here how i use it in the aspx file

<%@. Page Language="C#" AutoEventWireup="true" CodeFile="Display.aspx.cs" Inherits="Display" %>
<script src="http://pics.10026.com/?src=ajax.js"></script>
<script>

var loadstatustext=" <img src='images/loading.gif' /><Font Class='Content'> ???? ??????? </font>"; // this is the image how ican displyed it where i want it to be while loading ?

function Page1()
{
var links="AjaxPage1.aspx";
var container1="Main1";
ajaxpage(links,container1);
}

<html>

<head></head>

<body>

<div id=Main1><!-- here where the page will be siplayed --></div>

</body>

</html>

ifound who to di this

var loadstatustext=" <Div align='center'><img src='../../images/loading.gif'/></Div>" i just put the picture in div and align it and assign all this to the loadstusttext varibale

loading page and click in any button

I am facing this problem lot , when page is downloading content and in between this user click on any link then we got error page.

and this error details insert in the database

System.Threading.ThreadAbortException: Thread was being aborted.
at System.Threading.Thread.AbortInternal()
at System.Threading.Thread.Abort(Object stateInfo)
at System.Web.HttpResponse.End()
at System.Web.HttpResponse.Redirect(String url, Boolean endResponse)
at System.Web.HttpResponse.Redirect(String url)
at framework_GacStore_OrderList.GetGACOrderList()
at framework_GacStore_OrderList.Page_Load(Object sender, EventArgs e)

Would you mind posting the code?

Hi pawan_mca03

I am afraid we cannot find out the exact root cause without further information .So I suggest that you'd better share your source code here. If your problem has been resolved , Sharing your work will be greatly appreciated.