Question

I got a query regarding adding dynamic buttons with dynamic onclick events on a set of updatepanels.

I’ve simplified the scenario as the code I have so far is way too long and tied up..I’ve created a test page with 3 update panels.

In terms of the actual page the first updatepanel will be for the filters which will in turn update the second update panel. 2nd update panel will consist of all the results, depending on filters..this will be a table of buttons.

On the click of any of these buttons on the second update panel, depending on the ID of the button the results will be generated in the last update panel.

The problem I’m facing is tieing in the button click event when the buttons are created.
When I create the button from the onclick from the first update panel, it adds it to the placeholder but the click event does not fire at all.

Here is some code from my testing page.

test.aspx

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

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
    <asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" />
</ContentTemplate>

</asp:UpdatePanel>


<asp:UpdatePanel ID="UpdatePanel2" runat="server" ChildrenAsTriggers="False" 
    UpdateMode="Conditional">
<ContentTemplate>

<asp:PlaceHolder id="ph2" runat="server"></asp:PlaceHolder>
</ContentTemplate>

</asp:UpdatePanel>


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

<ContentTemplate>
<asp:PlaceHolder id="ph3" runat="server"></asp:PlaceHolder>
</ContentTemplate>

</asp:UpdatePanel>

Codebehind:

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

    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        Button up2button = new Button();
        up2button.ID = "up2button";
        ph2.Controls.Add(up2button);
        up2button.Click += new EventHandler(up2button_Click); // Not being registered?

        AsyncPostBackTrigger trigger1 = new AsyncPostBackTrigger();
        trigger1.ControlID = "up2button";
        trigger1.EventName = "Click";
        UpdatePanel2.Triggers.Add(trigger1);

        ScriptManager1.RegisterAsyncPostBackControl(up2button);

        UpdatePanel2.Update();

    }

    protected void up2button_Click(object sender, EventArgs e) { //and not being fired
        Button up3button = new Button();
        up3button.ID = "up3button";
        up3button.Click += new EventHandler(up3button_click);
        ph3.Controls.Add(up3button);


        AsyncPostBackTrigger trigger1 = new AsyncPostBackTrigger();
        trigger1.ControlID = "up3button";
        trigger1.EventName = "Click";
        UpdatePanel3.Triggers.Add(trigger1);
        UpdatePanel3.Update();
    }

    protected void up3button_click(object sender, EventArgs e) {


    }
}

Thankyou for your time.

Answer 1

here’s a quick sample, I find on the internet:

I’ve used a placeholder to hold the dynamically created controls – the button and textboxes on that button’s click event.

and the code:

   protected void Page_Load(object sender, EventArgs e)
    {
        if (IsPostBack)
        {
            if (ViewState["Add"] != null)
            {
                Button add = new Button();
                add.Text = "Add";
                add.Click += new EventHandler(add_Click);
                PlaceHolder1.Controls.Add(add);
            }
            if (ViewState["textboxes"] != null)
            {
                int count = 0;
                count = (int)ViewState["textboxes"];
                for (int i = 0; i < count; i++)
                {
                    textbox  textbox_foradd = new TextBox();
                    textbox_foradd.ID = "textadd" + (i + 1).ToString();
                    PlaceHolder1.Controls.Add(textbox_foradd);
                }
            }
        }

    }

    void add_Click(object sender, EventArgs e)
    {
        int count = 1;
        if (ViewState["textboxes"] != null)
        {
            count += Convert.ToInt32(ViewState["textboxes"]);
        }
        TextBox textbox_foradd = new TextBox();
        textbox_foradd.ID = "textadd" + count.ToString();
        PlaceHolder1.Controls.Add(textbox_foradd);
        ViewState["textboxes"] = count;
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        Button add = new Button();
        add.Text = "Add";
        PlaceHolder1.Controls.Add(add);
        ViewState["Add"] = 1;
    }