Event getting called 2 times indside an Update Panel.

[rawatgaurav81]

I had a question on updatepanel. I had a simple form where I had one update panel.It contains a tab container which
contains 3 tabs.Now I had set auto-postback of this container to true.I am not able to understand why my activetabchanged
event is being called 2 times.Normally as is the case with server controls,it should be called only once.The code is given below:

<form id="form1" runat="server">
    <div>
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
 
        <asp:UpdatePanel ID="UpdatePanel1" runat="server" EnableViewState="False">
            <ContentTemplate>
                <cc1:tabcontainer id="TabContainer1" runat="server" activetabindex="2" autopostback="True"
                    onactivetabchanged="TabContainer1_ActiveTabChanged" width="600px"><cc1:TabPanel runat="server" HeaderText="TabPanel1" ID="TabPanel1"><HeaderTemplate>
home
</HeaderTemplate>
</cc1:TabPanel>
<cc1:TabPanel runat="server" HeaderText="TabPanel2" ID="TabPanel2"><HeaderTemplate>
settings
</HeaderTemplate>
</cc1:TabPanel>
<cc1:TabPanel runat="server" HeaderText="TabPanel3" ID="TabPanel3"><HeaderTemplate>
Analysis
</HeaderTemplate>
</cc1:TabPanel>
</cc1:tabcontainer>
            </ContentTemplate>
        </asp:UpdatePanel>
 
    </div>        
    </form>
Code behind code is :
public partial class Test2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
 
    }
    protected void TabContainer1_ActiveTabChanged(object sender, EventArgs e)
    {
        Thread.Sleep(4000);
        //Do some processing herer.
    }
}

[terminul]

Hi Rawat,

This is apparently an issue/bug with the Ajax Control Toolkit, as yet there is no resolution. People are getting the same problems as you are, there is however a workaround.

This bug is currently lodged at http://www.codeplex.com/AtlasControl...rkItemId=11855

The workaround is simple enough, apparently the bug is caused by 2 post back events being raised separately, once by asp ajax and once by the toolkit itself.
I'm vaguely sure about this but the work around is here.

in your code behind

where u had

protected void TabContainer1_ActiveTabChanged(object sender, EventArgs e)
    {
        Thread.Sleep(4000);
        //Do some processing herer.
    }
 

just add a private bool set it to true (or u can reverse the logic - set it to false then within the ActiveTabChanged change it to true). and all u have to do is encapsulate the code u want to perform within the if statement

private bool isPageLoaded = true;
protected void TabContainer1_ActiveTabChanged(object sender, EventArgs e)
    {
        if (isPageLoaded)
        {
            isPageLoaded = false;
            Thread.Sleep(4000);
            //Do some processing herer.
        }        
    }
 

CAVEAT: I don't think this workaround actually stops double posting, just merely lets ur code run once instead of twice

[rawatgaurav81]

Hi Terminul,
Thanks for the reply....yeah i am already doing that in my application.But my application is a bit complex so using a private variable would not suffice because everytime a page is requested the variable would be initialized to its intial value and using static variables in a web application is always risky so I had to contend with a session variable to maintian its values across requests.
Hope micrososft fix this bug

Cheeeeerssss
Gaurav

Hi Rawat,

This is apparently an issue/bug with the Ajax Control Toolkit, as yet there is no resolution. People are getting the same problems as you are, there is however a workaround.

This bug is currently lodged at http://www.codeplex.com/AtlasControl...rkItemId=11855

The workaround is simple enough, apparently the bug is caused by 2 post back events being raised separately, once by asp ajax and once by the toolkit itself.
I'm vaguely sure about this but the work around is here.

in your code behind

where u had

protected void TabContainer1_ActiveTabChanged(object sender, EventArgs e)
    {
        Thread.Sleep(4000);
        //Do some processing herer.
    }
 

just add a private bool set it to true (or u can reverse the logic - set it to false then within the ActiveTabChanged change it to true). and all u have to do is encapsulate the code u want to perform within the if statement

private bool isPageLoaded = true;
protected void TabContainer1_ActiveTabChanged(object sender, EventArgs e)
    {
        if (isPageLoaded)
        {
            isPageLoaded = false;
            Thread.Sleep(4000);
            //Do some processing herer.
        }        
    }
 

CAVEAT: I don't think this workaround actually stops double posting, just merely lets ur code run once instead of twice

[ashar09]

Hi I got similar issue of getting dual postback on ActivetabChanged .

WorkAround:
1- set Autopostback to False;
2- Set the TabChanged event like this :

    <ajaxToolkit:TabContainer ID="tabAllowBlock" runat="server"   
                       AutoPostBack="false" 
                       ScrollBars="Auto" 
                       ActiveTabIndex="0"   
                       OnClientActiveTabChanged="LoadAllowBlock" 
                       OnActiveTabChanged="tabAllowBlock_ActiveTabChanged"  >
 

3-Write a javaScript Function LoadAllowBlock() in my case :
Here u can casue a postback such tat tabAllowBlock_ActiveTabChanged
gets fired.
This is how i Did :

function LoadAllowBlock() {
    __doPostBack('ctl00_BodyContentMid_tabAllowBlock', '');
}

__doPostback requires the Client ID of the TabContainer.

4- write ur logic in Code Behind for Tabchange

protected void tabAllowBlock_ActiveTabChanged(object sender, EventArgs e)
        {
            if (tabAllowBlock.ActiveTabIndex == 0) 
            {
                //your Code
             }
            else   
            {
               //your Code 
            }
 
 
        }

Hope it Resolves the Issue :)
Any queries If any can revert back at:<email removed>

[altafbytes]

Hi,

Your solution is good it's working fine.
But i am using it in child page(Of MasterPage) .
the event TabContainer1_ActiveTabChanged is not getting fire.

thanks in advance.

[ashar09]

Make sure u have added it to the attribute "OnActiveTabChanged" for the TabContainer .