通过HtmlTextWriter呈现的动态创建的控件未触发事件

Question

I have a simple ASP.Net page with a button and a Literal Control on it. On button click i am generating a new dynamic control (imagebutton) and rendering it via HtmlTextWriter to the Literal. On control creation i am also adding an onClick Event which is not getting fired. Here is my code:

aspx

    <asp:Button ID="btnCreate" runat="server" Text="Create" OnClick="btnCreate_Click" />
    <asp:Literal ID="lit" runat="server"></asp:Literal>

cs

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

    }

    protected void btnCreate_Click(object sender, EventArgs e)
    {
        ImageButton dynBtn = new ImageButton();
        dynBtn.ID = "1";
        dynBtn.ImageUrl = "http://cdn.mysitemyway.com/etc-mysitemyway/icons/legacy-previews/icons/matte-blue-and-white-square-icons-symbols-shapes/118240-matte-blue-and-white-square-icon-symbols-shapes-power-button.png";
        dynBtn.Click += new ImageClickEventHandler(dynBtn_click);
        lit.Text = RenderControl(dynBtn);
    }

    private void dynBtn_click(object sender, ImageClickEventArgs e)
    {
        Page.Response.Write("hello!");
    }

    private string RenderControl(Control control)
    {
        StringBuilder sb = new StringBuilder();
        StringWriter sw = new StringWriter(sb);
        HtmlTextWriter writer = new HtmlTextWriter(sw);

        control.RenderControl(writer);
        return sb.ToString();
    }
}

The control is getting created without any errors but the event is not fireing.

Answer 1

尝试这个

lit.Controls.Add(dynBtn);

Answer 2

Adding your ImageButton to an ASP.NET container would make your life easier, and would be more in line with the way of doing things in the framework. You can add your button to different types of Web controls, depending on the type of HTML container that you want.

Option 1 - PlaceHolder

A PlaceHolder is not rendered as an HTML element. Its output contains only the controls that have been added to it. Among the 3 container controls presented here, it is the most similar to the Literal control.

<asp:PlaceHolder ID="container" runat="server" />

Option 2 - Panel

A Panel is rendered as as div element.

<asp:Panel ID="container" runat="server" />

Option 3 - Label

A Label is rendered as a span element.

<asp:Label ID="container" runat="server" />

Adding the control

The following statement can be used in code-behind to add the ImageButton to any of the 3 types of ASP.NET containers mentioned above:

container.Controls.Add(dynBtn);