Reputation: 627

UpdatePanel not working on first click

I have an ASPX page with a ScriptManager control, some LinkButton controls and a PlaceHolder control. Each LinkButton will add (OnPageLoad) a particular User Control in the PlaceHolder control. Each UserControl has a ScriptManagerProxy control and an UpdatePanel (UpdateMode=Conditional) which contains some CheckBox (AutoPostback=true) controls and a GridView.

The problem is that when you click a CheckBox control, it is checked, but nothing happens. When you click it again, it is unchecked and it causes a full PostBack of the entire page. Subsequent clicks of the CheckBox controls work asynchronously as they should.

User Control 1: Markup

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="UserControl1.ascx.cs" Inherits="UserControls_UserControl1" %>


<div>

<asp:ScriptManagerProxy ID="smp1" runat="server" />

<asp:UpdatePanel ID="up1" UpdateMode="Conditional" runat="server">
<ContentTemplate>

<h1>CheckBox Test 1</h1>

<asp:Panel ID="pnlOptions" runat="server" Visible="true">
    <asp:Panel ID="pnlCheckTest1" runat="server">
        <asp:CheckBox ID="chkCheckTest1" 
                      AutoPostBack="true"
                      Text="Test 1" 
                      OnCheckedChanged="chkCheckTest1_CheckChanged"
                      runat="server" />
    </asp:Panel>
    <asp:Panel ID="pnlCheckTest2" runat="server">
        <asp:CheckBox ID="chkCheckTest2" 
                      AutoPostBack="true"
                      Text="Test 2" 
                      OnCheckedChanged="chkCheckTest2_CheckChanged"
                      runat="server" />
    </asp:Panel> 
</asp:Panel>

<br /><br />

<div>
<asp:Label ID="lblTestCheck1" runat="server" />
</div>

</ContentTemplate>
</asp:UpdatePanel>

</div>

User Control 1: Code

public partial class UserControls_UserControl1 : System.Web.UI.UserControl
{

    protected void chkCheckTest1_CheckChanged(object sender, EventArgs e)
    {
        lblTestCheck1.Text = "Tiny";
    }

    protected void chkCheckTest2_CheckChanged(object sender, EventArgs e)
    {
        lblTestCheck1.Text = "Large";
    }
}

User Control 2: Markup

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="UserControl2.ascx.cs" Inherits="UserControls_UserControl2" %>


<div>

<asp:ScriptManagerProxy ID="smp1" runat="server" />

<asp:UpdatePanel ID="up1" UpdateMode="Conditional" runat="server">
<ContentTemplate>

<h1>CheckBox Test 2</h1>

<asp:Panel ID="pnlOptions" runat="server" Visible="true">
    <asp:Panel ID="pnlCheckTest1" runat="server">
        <asp:CheckBox ID="chkCheckTest1" 
                      AutoPostBack="true"
                      Text="Test 1" 
                      OnCheckedChanged="chkCheckTest1_CheckChanged"
                      runat="server" />
    </asp:Panel>
    <asp:Panel ID="pnlCheckTest2" runat="server">
        <asp:CheckBox ID="chkCheckTest2" 
                      AutoPostBack="true"
                      Text="Test 2" 
                      OnCheckedChanged="chkCheckTest2_CheckChanged"
                      runat="server" />
    </asp:Panel> 
</asp:Panel>

<br /><br />

<div>
<asp:Label ID="lblTestCheck2" runat="server" />
</div>

</ContentTemplate>
</asp:UpdatePanel>

</div>

User Control 2: Code

public partial class UserControls_UserControl2 : System.Web.UI.UserControl
{

    protected void chkCheckTest1_CheckChanged(object sender, EventArgs e)
    {
        lblTestCheck2.Text = "Small";
    }

    protected void chkCheckTest2_CheckChanged(object sender, EventArgs e)
    {
        lblTestCheck2.Text = "Big";
    }
}

Main Page: Markup

<%@ Page Title=""  Language="C#" AutoEventWireup="true"CodeFile="CheckBoxTest.aspx.cs" Inherits="CheckBoxTest" %>
<html>
<head id="head1" runat="server">
<title>Check Box Test</title>
</head>

<body>
<form id="form1" runat="server">
<asp:ScriptManager ID="sm1" runat="server" />


<div id="Div1" runat="server">
    <asp:LinkButton ID="lbCheckTest1" runat="server" Text="Check Test 1" 
            onclick="lbCheckTest1_Click" />
    <br />
    <asp:LinkButton ID="lbCheckTest2" runat="server" Text="Check Test 2" 
            onclick="lbCheckTest2_Click" />
</div>

<br /><br /><br /><br />

<div id="Div2" runat="server">
    <asp:PlaceHolder 
        ID="phTable"
        runat="server" />        
</div>
</form>
</body>
</html>

Main Page: Code

public partial class CheckBoxTest : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (Page.IsPostBack)
        {
            try
            {
                Control ctrl = LoadControl(Session["CurrentControl"] as String);
                phTable.Controls.Add(ctrl);
            }
            catch
            {
                // ...
            }
        }
    }

    protected void lbCheckTest1_Click(object sender, EventArgs e)
    {
        Session["CurrentControl"] = "~/UserControls/UserControl1.ascx";
        Control ctrl = LoadControl(Session["CurrentControl"] as String);
        phTable.Controls.Clear();
        phTable.Controls.Add(ctrl);
    }

    protected void lbCheckTest2_Click(object sender, EventArgs e)
    {
        Session["CurrentControl"] = "~/UserControls/UserControl2.ascx";
        Control ctrl = LoadControl(Session["CurrentControl"] as String);
        phTable.Controls.Clear();
        phTable.Controls.Add(ctrl);
    }
}

Upvotes: 0

Answers (2)

Sheldon Cooper

Reputation: 627

It turns out the issue had nothing to do with the UpdatePanel. The problem was with the dynamically loaded User Controls.

ViewState is a problem with dynamically loaded controls. It is best to load them during the OnPageInit event during the Execution Life Cycle. Also, to ensure that ViewState works properly, assign the control a valid ID;

    protected void Page_Init(object sender, EventArgs e)
    {
        if (Page.IsPostBack)
        {
            try
            {
                phTable.Controls.Clear();
                Control ctrl = LoadControl(Session["CurrentControl"] as String);
                ctrl.ID = Session["CurrentControlID"].ToString();
                phTable.Controls.Add(ctrl);
            }
            catch
            {
                // Handle Error...
            }
        }
    }


protected void lbCheckTest1_Click(object sender, EventArgs e)
{
    Session["CurrentControl"] = "~/UserControls/UserControl1.ascx";
    Session["CurrentControlID"] = "UserControl1";        
    Control ctrl = LoadControl(Session["CurrentControl"] as String);
    ctrl.ID = Session["CurrentControlID"].ToString();
    phTable.Controls.Clear();
    phTable.Controls.Add(ctrl);
}

Upvotes: 1

sangram parmar

Reputation: 8726

try this

<asp:UpdatePanel runat="server"><%--your updatepanel--%>
    <ContentTemplate>
    <%--something that you want to update on checkbox check change event--%>
    </ContentTemplate>
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="your_checkbox_control_id" EventName="CheckedChanged" />
        <%--add AsyncPostBackTrigger for checkbox event --%>
    </Triggers>
</asp:UpdatePanel>

Upvotes: 0

UpdatePanel not working on first click

Answers (2)

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