CODEWITHSUNDEEP
asp.netupdatepanel
Alberto Nuti
Alberto Nuti

Reputation: 47

asp.net updatepanel inside usercontrol reload the whole control

I want to create a user control that represents a progress bar.

ASCX:

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="ProgressBar.ascx.cs" Inherits="A2Controls.Controls.ProgressBar" %>

<div class="progress">
    <div class="progress-bar" role="progressbar" aria-valuenow="<%# this.Value %>" aria-valuemin="0" aria-valuemax="100" style="width: <%# this.Value %>%">
        <span class="sr-only"><%# this.Value %> Complete</span>
    </div>
</div>

Code Behind:

public partial class ProgressBar : System.Web.UI.UserControl
{
    public int Value { get; set; }

    protected void Page_Load(object sender, EventArgs e)
    {

    }
}

ASPX:

<asp:UpdatePanel runat="server">
    <ContentTemplate>
        <asp:Timer runat="server" ID="clock" OnTick="clock_Tick" Interval="1000" Enabled="true"></asp:Timer>
        <uc1:ProgressBar runat="server" ID="ProgressBar" />
    </ContentTemplate>
    <Triggers  >
        <asp:AsyncPostBackTrigger ControlID="clock" EventName="Tick" />
    </Triggers>
</asp:UpdatePanel>

Code Behind:

protected void clock_Tick(object sender, EventArgs e)
{
    this.ProgressBar.Value++;
}

The problem is that every time the tick function is called, the updatepanel refreh and reload the whole usercontrol (calling the constructor I mean)! I've tried to put the updatepanel logic inside the usercontrol but there is no difference.

How can I prevent the usercontrol re-instantiate again?

Upvotes: 2

Views: 793

Answers (1)

dario
dario

Reputation: 5259

You have to change your Value property to this:

public int Value
{
    get
    {
        if (ViewState["Value"] != null)
            return (int)ViewState["Value"];
        else
            return 0;
    }
    set
    {
        ViewState["Value"] = value;
    }
}

In this way you keep the property's value across postbacks.

HTTP is a stateless protocol. Unfortunately you have to use some kind of trick to persist data across requests like the ViewState does. You better have a look here and here to deeply understand that there's nothing wrong here.

Upvotes: 1

Related Questions