handle multiple asynchronous calls

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610 Points

handle multiple asynchronous calls

May 09, 2007 06:46 AM|benderm|LINK

I'm looking to handle multiple updatePanel asynchronous updates at a time. The don't have to update all the panels at the same time, I think that is impossible anyways, but I should handle each at a time and make a queue of unhandled updates. I have 3 update panels, each with a button. The button click updates it's specific panel. If I click on another update button before the the first update has ended, I don't get the result from the first update. The default is to abort the previous asynchronous call, how can I make it handle my requirment?

I have tried to make a variation of the following link but ran into problems with JScript: http://ajax.asp.net/docs/tutorials/ExclusiveAsyncPostback.aspx

Hopefully someone out there has run into this before, thanks for the help in advance.

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Raymond Wen...

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25004 Points

3737 Posts

Re: handle multiple asynchronous calls

May 11, 2007 02:47 AM|Raymond Wen - MSFT|LINK

Hi,

You can use a queue to cache all of the request, and submit them one by one.

Please try this:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>


<!DOCTYPE html PUBLIC "-//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" >
<head runat="server">
    <title>Untitled Page</title>
    

</head>
<body>
    <form id="form1" runat="server">
    <div>
         <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
    

    </div>
             
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
                <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" />
            </ContentTemplate>
        </asp:UpdatePanel>
             
        <asp:UpdatePanel ID="UpdatePanel2" runat="server">
            <ContentTemplate>
                <asp:Label ID="Label2" runat="server" Text="Label"></asp:Label>
                <asp:Button ID="Button2" runat="server" OnClick="Button2_Click" Text="Button" />
            </ContentTemplate>
        </asp:UpdatePanel>
         
        <asp:UpdatePanel ID="UpdatePanel3" runat="server">
            <ContentTemplate>
                <asp:Label ID="Label3" runat="server" Text="Label"></asp:Label>
                <asp:Button ID="Button3" runat="server" OnClick="Button3_Click" Text="Button" />
            </ContentTemplate>
        </asp:UpdatePanel>
        <asp:UpdateProgress ID="UpdateProgress1" runat="server" AssociatedUpdatePanelID="UpdatePanel1"
            DisplayAfter="0">
            <ProgressTemplate>
                Updating panel1
            </ProgressTemplate>
        </asp:UpdateProgress>
        <asp:UpdateProgress ID="UpdateProgress3" runat="server" AssociatedUpdatePanelID="UpdatePanel3"
            DisplayAfter="0">
            <ProgressTemplate>
                Updating panel3
            </ProgressTemplate>
        </asp:UpdateProgress>
        <asp:UpdateProgress ID="UpdateProgress2" runat="server" AssociatedUpdatePanelID="UpdatePanel2"
            DisplayAfter="0">
            <ProgressTemplate>
                Updating panel2
            </ProgressTemplate>
        </asp:UpdateProgress>
        <div id="AlertDiv">
           <span id="AlertMessage"></span>
        </div>
        

        

    

    <script type="text/javascript">
    Sys.Application.add_load(ApplicationLoadHandler)
    

    function ApplicationLoadHandler(sender, args)
    {
        var prm = Sys.WebForms.PageRequestManager.getInstance();
        if (!prm.get_isInAsyncPostBack())
        {
            prm.add_initializeRequest(InitializeRequest);
            prm.add_endRequest(CompleteRequest);
        }
    }
    // initialize a queue
    var myQueue = new Array();
    

    function CompleteRequest(sender, args)
    {
        if(myQueue.length > 0)
        {// fire correspond event again of the item cached
            $get(myQueue[0].id).click();
            Array.removeAt(myQueue, 0);
        }
    }
    function InitializeRequest(sender, args)
    {
        var prm = Sys.WebForms.PageRequestManager.getInstance();
        if (prm.get_isInAsyncPostBack())
        {// if it's working on another request, cache the current item that cause the request
            args.set_cancel(true);
            Array.add(myQueue, args.get_postBackElement());
        }
    }


    if(typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();
    

    </script>
    

    </form>
</body>
</html>

Hope this helps.

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Raymond Wen...

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25004 Points

3737 Posts

Re: handle multiple asynchronous calls

May 11, 2007 02:52 AM|Raymond Wen - MSFT|LINK

Code behind:

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;


public partial class _default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
    }


    protected void Button1_Click(object sender, EventArgs e)
    {
        System.Threading.Thread.Sleep(2000);
        Label1.Text = DateTime.Now.ToLongTimeString();
    }
    protected void Button2_Click(object sender, EventArgs e)
    {
        System.Threading.Thread.Sleep(2000);
        Label2.Text = DateTime.Now.ToLongTimeString();
    }
    protected void Button3_Click(object sender, EventArgs e)
    {
        System.Threading.Thread.Sleep(2000);
        Label3.Text = DateTime.Now.ToLongTimeString();
    }
}

Reply

benderm

Member

610 Points

337 Posts

Re: handle multiple asynchronous calls

May 11, 2007 04:25 AM|benderm|LINK

Your example works great, I could almost just copy and past the javascript code into my project!! I had a little trouble because my buttons had an animation extender onClick, and that somehow stopped the javascript from working. The animation used to disable the button after one click. Can you help me with adding that functionality? I've tried to add to Page_load

        Button1.Attributes.Add("onclick", "this.disabled=true;");
        Button2.Attributes.Add("onclick", "this.disabled=true;");
        Button3.Attributes.Add("onclick", "this.disabled=true;");

to your example but then no update happens when the buttons are clicked.

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This marks your thread as Resolved so we will all know you have been helped.

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benderm

Member

610 Points

337 Posts

Re: handle multiple asynchronous calls

May 11, 2007 06:03 AM|benderm|LINK

I have also found some strange behavior when I use this javascript in Firefox, firefox does a full postback for all the queued items and doesn't show the queued items PpdateProgress?? IE 6 handles them fine...

Don't forget to click "Mark as Answer" on the post that helped you.
This marks your thread as Resolved so we will all know you have been helped.

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Raymond Wen...

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25004 Points

3737 Posts

Re: handle multiple asynchronous calls

May 11, 2007 11:47 AM|Raymond Wen - MSFT|LINK

You may try to cache the request, not the control.
function InitializeRequest(sender, args)
{
var prm = Sys.WebForms.PageRequestManager.getInstance();
if (prm.get_isInAsyncPostBack())
{
args.set_cancel(true);
Array.add(myQueue, args.get_request());
}
}
And create an Sys.Net.XMLHttpExecutor object to send it in CompleteRequest.

The demo I wrote is used to illustrate the idea, but may not work with all browsers. You need to extend it.

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aalok43

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6 Posts

Re: handle multiple asynchronous calls

Jun 04, 2007 08:10 AM|aalok43|LINK

hey!

Can we load data for multiple UpdatePanel at same time. I mean, I have 4 UP on 1 page, and initially when my page gets loaded none of the UP will show any data. Then using Timer control I make a asyn post back and start updating the UP. But this happens 1 by 1, i.e. it will first load UP1 then UP2 and so on..cant we load data for all UP in one go..or it its not possible [:^)]

Thanks and regards,

AaLoK

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Raymond Wen...

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25004 Points

3737 Posts

Re: handle multiple asynchronous calls

Jun 04, 2007 08:59 PM|Raymond Wen - MSFT|LINK

Hi,

You can call the Update() method for all of them.

Reply

lostintime

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3 Posts

Re: handle multiple asynchronous calls

Aug 02, 2007 11:47 AM|lostintime|LINK

Hi Raymond

Is there some way the requests can be made to operate at the same time? Currently they are being queued but lets say we need the action of 3 buttons to operate simultaneously.Is this possible?

This can be seen here at pageflakes.com. If you have 2 'flakes' each having refresh icon/button, clicking on them one after the another brings out the behavior that I asked in my query.

Thanks for your replies

Sandy

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donkaiser

Member

9 Points

156 Posts

Re: handle multiple asynchronous calls

Aug 03, 2007 02:59 PM|donkaiser|LINK

Sorry for my ignorance with javascript.

how do you send Sys.Net.XMLHttpExecutor object to CompleteRequest?

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gt1329a

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Re: handle multiple asynchronous calls

Aug 03, 2007 06:26 PM|gt1329a|LINK

lostintime

Hi Raymond

Is there some way the requests can be made to operate at the same time? Currently they are being queued but lets say we need the action of 3 buttons to operate simultaneously.Is this possible?

This can be seen here at pageflakes.com. If you have 2 'flakes' each having refresh icon/button, clicking on them one after the another brings out the behavior that I asked in my query.

Thanks for your replies

Sandy

Pageflakes uses GET requests to web services, not UpdatePanels. As far as I know, you can't execute multiple simultaneous partial postbacks in the current framework.

Encosia - ASP.NET, jQuery, AJAX, and more.

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Reply

aminoplacid

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0 Points

2 Posts

Re: handle multiple asynchronous calls

Aug 08, 2007 07:47 PM|aminoplacid|LINK

This is a great example! Is there a way while queueing the Async postbacks to fire up the UpdateProgress so that the user can see that those that are in the queue are not neglected and are waiting to process? Thanks!

Reply

ishfaque.hus...

Member

20 Points

9 Posts

Re: handle multiple asynchronous calls

Sep 06, 2007 07:51 AM|ishfaque.hussain@gmail.com|LINK

Dear Raymond Wen,

I am also facing problems in the same context. I hope you will help me. Let me explain the problem.

I have same form as yours but instead of three buttons i have only one. everytime user clicks the button a call to database is made using a new Asynchronous call and the results are show in the grid on completion. For every database resule there is a new row in the grid. The problem is, every asynchronous call executes after the previous one is completed showing a behaviour of queues. However i need pure asynchronous tasks that is the results of less time consuming should appear first even if it was started at last. for more clarity here is code for both aspx and aspx.csIshfaq. before executing this code please make sure the connection string is ok for your machine. on execution click the button immidiately more than one times and see the start and end times.

Thanks in advance.

Regards,

Ishfaq Hussain

-----------------------------Sample.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Sample.aspx.cs" Inherits="_sample" %>
<!DOCTYPE html PUBLIC "-//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" >

<head id="Head1" runat="server">

<title>Untitled Page</title>

</head>
<body>

<form id="form1" runat="server">

<div>

<asp:ScriptManager ID="ScriptManager1" runat="server">

</asp:ScriptManager>

</div>

<asp:UpdatePanel ID="UpdatePanel1" runat="server">

<ContentTemplate>

<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>

<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" /> 

<asp:GridView ID="gridTasks" runat="server">

</asp:GridView>

</ContentTemplate>

</asp:UpdatePanel>

 

<asp:UpdateProgress ID="UpdateProgress1" runat="server" AssociatedUpdatePanelID="UpdatePanel1"

DisplayAfter="0">

<ProgressTemplate>

<img src="indicator.gif" />

</ProgressTemplate>

</asp:UpdateProgress>

<asp:UpdatePanel ID="UpdatePanel2" runat="server">

<ContentTemplate>

<asp:Label ID="Label2" runat="server" Text="Label" Visible="False"></asp:Label>

<asp:Button ID="Button2" runat="server" OnClick="Button2_Click" Text="Button" Visible="False" />

</ContentTemplate>

</asp:UpdatePanel>

 

<asp:UpdatePanel ID="UpdatePanel3" runat="server">

<ContentTemplate>

<asp:Label ID="Label3" runat="server" Text="Label" Visible="False"></asp:Label>

<asp:Button ID="Button3" runat="server" OnClick="Button3_Click" Text="Button" Visible="False" />

</ContentTemplate>

</asp:UpdatePanel>

 

<asp:UpdateProgress ID="UpdateProgress3" runat="server" AssociatedUpdatePanelID="UpdatePanel3"

DisplayAfter="0">

<ProgressTemplate>

Updating panel3

</ProgressTemplate>

</asp:UpdateProgress>

<asp:UpdateProgress ID="UpdateProgress2" runat="server" AssociatedUpdatePanelID="UpdatePanel2"

DisplayAfter="0">

<ProgressTemplate>

Updating panel2

</ProgressTemplate>

</asp:UpdateProgress>

<div id="AlertDiv">

<span id="AlertMessage"></span>

</div>

<script type="text/javascript">
Sys.Application.add_load(ApplicationLoadHandler)

function ApplicationLoadHandler(sender, args)
{
var prm = Sys.WebForms.PageRequestManager.getInstance();if (!prm.get_isInAsyncPostBack())
{

prm.add_initializeRequest(InitializeRequest);

prm.add_endRequest(CompleteRequest);

}

}

// initialize a queue
var myQueue = new Array();

function CompleteRequest(sender, args)
{
if(myQueue.length > 0)
{// fire correspond event again of the item cached

$get(myQueue[0].id).click();

Array.removeAt(myQueue, 0);

}

}
function InitializeRequest(sender, args)
{
var prm = Sys.WebForms.PageRequestManager.getInstance();
if (prm.get_isInAsyncPostBack())

{// if it's working on another request, cache the current item that cause the request
args.set_cancel(true);
Array.add(myQueue, args.get_postBackElement());

}

}
if(typeof(Sys) !== "undefined") Sys.Application.notifyScriptLoaded();

</script>

</form>
</body>

</html>

-----------------------------Sample.aspx.cs

using System;

using System.Data;

using System.Data.SqlClient;

using System.Configuration;

using System.Collections;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

public partial class _sample : System.Web.UI.Page

{
DataTable dt = new DataTable();
private SqlConnection conn;
private SqlCommand command;
private SqlDataReader _reader;
private int ThreadCount=0;protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{

dt.Columns.Add("Task ID");
dt.Columns.Add("Order ID");
dt.Columns.Add("Start Time");
dt.Columns.Add("End Time");
dt.Columns.Add("Order Amount");
ViewState["dt"] = dt;Session["ThreadCount"] = ThreadCount;
}

dt = (DataTable)ViewState["dt"];
ThreadCount =(int) Session["ThreadCount"];
}
protected void Button1_Click(object sender, EventArgs e)
{

ThreadCount++;
Session["ThreadCount"] = ThreadCount;
//Response.Write(Request.QueryString["values"]);

//Response.Write("<p>Request No" + ThreadCount.ToString() + "</p>");

Label1.Text = ThreadCount.ToString();
Random rand = new Random();
int n = rand.Next(10000, 11077);

//Guid taskId = Guid.NewGuid();
int taskId = ThreadCount;
string stime = System.DateTime.Now.TimeOfDay.ToString();
Tasks task = new Tasks();
//task.guid = taskId;

task.TaskID = taskId;

task.OrderID = n.ToString();

task.StartTime = stime;

//AddListViewItem(task.guid, int.Parse(task.OrderID), task.StartTime);
AddListViewItem(task.TaskID, int.Parse(task.OrderID), task.StartTime);PageAsyncTask asynctask = new PageAsyncTask(BeginAsyncOperation, EndAsyncOperation, EndTimeOutInvoke, task);
RegisterAsyncTask(asynctask);

}

IAsyncResult BeginAsyncOperation(object sender, EventArgs e, AsyncCallback cb, object state)
{
Tasks task = (Tasks)state;
conn = new SqlConnection("Data Source=localhost;Initial Catalog=Northwind; Integrated Security=true; Asynchronous Processing=true");
command = new SqlCommand();
command.CommandText = "WAITFOR DELAY '0:0:0" + new Random().Next(1, 9) + "' SELECT isnull(sum((UnitPrice * Quantity)-Discount),0) from [Order Details] WHERE OrderID = " + int.Parse(task.OrderID);

//command.CommandText = "SELECT isnull(sum((UnitPrice * Quantity)-Discount),0) from [Order Details] WHERE OrderID = " + n;

command.Connection = conn;

conn.Open();

//SqlDataReader dr = command.ExecuteReader();

//etime = System.DateTime.Now.TimeOfDay.ToString();

//DataTable dt = new DataTable();

//dt.Load(dr);
return command.BeginExecuteReader(cb, task);
}
void EndAsyncOperation(IAsyncResult ar)
{

_reader = command.EndExecuteReader(ar);
string etime = System.DateTime.Now.TimeOfDay.ToString();DataTable tempdt = new DataTable();
tempdt.Load(_reader);
UpdateListViewItem((Tasks)ar.AsyncState, float.Parse(tempdt.Rows[0][0].ToString()), etime);
}

public void EndTimeOutInvoke(IAsyncResult result)
{

//if (cnx != null && cnx.State != ConnectionState.Closed)

// cnx.Close();
Response.Write("TimeOut");
Response.End();

}
protected void Page_PreRenderComplete(object sender, EventArgs e)
{

//gridTasks.DataSource = dt;

//gridTasks.DataBind();

}

private void AddListViewItem(
//Guid guid,
int taskID,
int testNumber,
string sTime)
{
DataRow drow = dt.NewRow();
//drow["Task ID"] = guid.ToString();
drow["Task ID"] = taskID.ToString();
drow["Order ID"] = testNumber.ToString();
drow["Start Time"] = sTime;
drow["End Time"] = "---";
drow["Order Amount"] = "---";
dt.Rows.Add(drow);

gridTasks.DataSource = dt;

gridTasks.DataBind();

}

private void UpdateListViewItem(
Tasks task,
float Amount,string eTime
)

{

try

{
int i = 0;foreach (DataRow drow in dt.Rows)
{

//if ((Guid)lvi.Tag == guid)

//Guid g = new Guid(drow["Task ID"].ToString());
int tid = int.Parse(drow["Task ID"].ToString());if (tid == task.TaskID)
{

//drow["End Time"] = eTime;

//drow["Order Amount"] = Amount.ToString();
dt.Rows[i]["End Time"] = eTime;dt.Rows[i]["Order Amount"] = Amount.ToString();
dt.AcceptChanges();
break;
}

i++;

}

gridTasks.DataSource = dt;

gridTasks.DataBind();

}
catch (Exception ex)
{

}

}

protected void Button2_Click(object sender, EventArgs e)
{
System.Threading.Thread.Sleep(2000);Label2.Text = DateTime.Now.ToLongTimeString();
}
protected void Button3_Click(object sender, EventArgs e)
{

System.Threading.Thread.Sleep(2000);
Label3.Text = DateTime.Now.ToLongTimeString();
}

}

Reply

ishfaque.hus...

Member

20 Points

9 Posts

Hoe to handle multiple asynchronous calls

Sep 06, 2007 08:14 AM|ishfaque.hussain@gmail.com|LINK

Hi Dear Sandy,

I am facing the same problem as you. Did you get any solution for this?

I need this ugently. Please let me know.

Thanks and Regards,

Ishfaq Hussain

This was your question at the forum:

Hi Raymond

Is there some way the requests can be made to operate at the same time? Currently they are being queued but lets say we need the action of 3 buttons to operate simultaneously.Is this possible?

This can be seen here at pageflakes.com. If you have 2 'flakes' each having refresh icon/button, clicking on them one after the another brings out the behavior that I asked in my query.

Thanks for your replies

Sandy

Reply

lostintime

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0 Points

3 Posts

Re: Hoe to handle multiple asynchronous calls

Sep 17, 2007 09:31 AM|lostintime|LINK

I have experimented a lot with UpdatePanels but like earlier posts point out, multiple requests cannot be done at the same time.

The only way I was able to do it was by creating the XmlHttpRequest object directly and then using it to make the request. However a new object has to be made each time (like when a button is clicked). Then simultenous requests worked for me using both GET and POST. The disadvantage is that you cannot retrieve or set the values of web controls at server side. This has to be done at client using JavaScript.

Sandy

Reply

wrayx1

Member

190 Points

90 Posts

Re: Hoe to handle multiple asynchronous calls

Sep 17, 2007 11:31 AM|wrayx1|LINK

I think you would run into a problem even with XmlHttpRequest, because somewhere I read it can only do 2 at once in most browsers and after that it queues them with some internal mechanism.

Reply

ishfaque.hus...

Member

20 Points

9 Posts

Re: Hoe to handle multiple asynchronous calls

Sep 18, 2007 11:46 PM|ishfaque.hussain@gmail.com|LINK

Thanks Sandy,

Can you please provide the sample code for this. I will be gratefull.

Regards

Ishfaq

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