Question

I am running into a problem with Ajax and C# asp.net. I am using Microsoft Visual Studio 2010.

First let me explain my web page.

I have script manager, and directly underneath that I have a update panel.

This is the dynamic placeholder I’ve been fiddling with.

http://www.denisbauer.com/ASPNETControls/DynamicControlsPlaceholder.aspx

Within my update panel, I have a dynamic control & a button.

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <asp:ScriptManager ID="ScriptManager1" runat="server" >
    </asp:ScriptManager>

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

        <ContentTemplate>
                <DBWC:DynamicControlsPlaceholder ID="DynamicControlsPlaceholder1" 
    runat="server">
            </DBWC:DynamicControlsPlaceholder>
            <br />

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

        </ContentTemplate>

        <Triggers>
            <asp:AsyncPostBackTrigger ControlID="Button1" EventName="Click" />
        </Triggers>

    </asp:UpdatePanel>

</asp:Content>

Now in my code behind:

I simply add 5 text boxes to a dynamic control. Page load;

protected void Page_Load(object sender, EventArgs e)
    {

        if (!Page.IsPostBack)
        {
            ViewState["id"] = 0;
        int id = (int)ViewState["id"];

        for (int i = 0; i < 5; i++)
        {
            id++;
            TextBox txt = new TextBox();
            txt.ID = id.ToString();
            DynamicControlsPlaceholder1.Controls.Add(txt);
            txt.Text = i.ToString();
        }
        ViewState["id"] = id;
        }

    }

Now all my button does is add another TextBox to the dynamic control pannel.

protected void Button1_Click(object sender, EventArgs e)
    {


        int id = (int)ViewState["id"];

        TextBox txt = new TextBox();
        txt.ID = id.ToString();
        DynamicControlsPlaceholder1.Controls.Add(txt);
        // DynamicControlsPlaceholder1.DataBind();
        txt.Text = id.ToString();

        id++;
       ViewState["id"] = id;

    }

* Note I am using a custom dynamic control panel so their ID’s are saved to the next page even though we have them creeated in a !Page.IsPostBack

The problem is that my button event handler only works once. I’m pretty sure its because the Ajax is calling a partial postback and it’s not recognizing it to call my button event handler.

I’m not sure, any help is appriciated.

Answer 1

Firebug works wonders for debugging ajax. “There were multiple controls with the same ID ‘5’.”

What a simple fix. Moved id++; to the top of Button1_Click event handler.

If you’re ever assuming ajax is breaking your event handler just because the breakpoint is not firing in the event handler, firebug may save you too!

There was absolutely nothing wrong with the event handler, but the code within it was causing an error and ajax wasn’t allowing it to break.