Asp.net:to call event handler of dynamically generated buttons?

Question

i have set enableviewstate property of linkbutton and label to true.also regenrating same buttons on postback in pageload event handler.but m not able to call onclick event handler of linkbutton.can u please tell me what is problem with code?

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

        List<LinkButton> listOfLinkButton = Session["ListOfLinkButton"] as List<LinkButton>;
        List<Label> listOfLabel = Session["ListOfLabel"] as List<Label>;
        if(listOfLabel!=null && listOfLinkButton!=null)
        {
            for (int i = 0; i < listOfLinkButton.Count; i++)
            {
                PlaceHolder1.Controls.Add(listOfLinkButton[i]);
                PlaceHolder1.Controls.Add(new LiteralControl("<br />"));
                PlaceHolder1.Controls.Add(listOfLabel[i]);
                PlaceHolder1.Controls.Add(new LiteralControl("<br />"));
            }
        }



}



protected void LinkButton_Click(object sender, EventArgs e)
{
    LinkButton linkButton = sender as LinkButton;

    Response.Redirect(linkButton.Attributes["LinkUrl"]);        
}
protected void Button1_Click1(object sender, EventArgs e)
{

    List<LinkButton> listOfLinkButton = new List<LinkButton>();
    List<Label> listOfLabel = new List<Label>();
    Rss rssDocumentObj = RssFileReader.GetRssDocumentData(TextBox1.Text);
    for (int j = 0; j < rssDocumentObj.ListOfChannel.Count; j++)
    {
        LinkButton linkButton = new LinkButton();
        linkButton.ID = "LinkButtonForChannelDynamicInPlaceHolder1Id" + j;
        linkButton.EnableViewState = true;
        linkButton.ForeColor = Color.Blue;
        linkButton.Font.Bold = true;
        linkButton.Font.Size = 18;
        linkButton.Font.Underline = true;
        linkButton.Text = rssDocumentObj.ListOfChannel[j].ChannelTitle.InnerText;
        linkButton.Click += new EventHandler(LinkButton_Click);
        linkButton.Attributes.Add("LinkUrl", rssDocumentObj.ListOfChannel[j].ChannelLink.InnerText);
        linkButton.Attributes.Add("onmouseover", "this.style.color = '#006699'");
        linkButton.Attributes.Add("onmouseout", "this.style.color = '#0000ff'");
        PlaceHolder1.Controls.Add(linkButton);
        listOfLinkButton.Add(linkButton);
        PlaceHolder1.Controls.Add(new LiteralControl("<br />"));
        Label label = new Label();
        label.ID = "LabelForChannelDynamicInPlaceHolder1Id" + j;
        label.EnableViewState = true;
        label.ForeColor = Color.DarkSlateGray;
        label.Text = rssDocumentObj.ListOfChannel[j].ChannelDescription.InnerText;
        PlaceHolder1.Controls.Add(label);
        listOfLabel.Add(label);
        PlaceHolder1.Controls.Add(new LiteralControl("<br />"));

        for (int i = 0; i < rssDocumentObj.ListOfChannel[j].ListOfItem.Count; i++)
        {
            LinkButton linkButtonForItem = new LinkButton();
            linkButtonForItem.ID = "LinkButtonDynamicInPlaceHolder1Id" + j + " " + i;
            linkButtonForItem.EnableViewState = true;
            linkButtonForItem.ForeColor = Color.Blue;
            linkButtonForItem.Font.Bold = true;
            linkButtonForItem.Font.Size = 14;
            linkButtonForItem.Font.Underline = false;
            linkButtonForItem.Text = rssDocumentObj.ListOfChannel[j].ListOfItem[i].ItemTitle.InnerText;
            linkButtonForItem.Click += new EventHandler(LinkButton_Click);
            linkButtonForItem.Attributes.Add("LinkUrl", rssDocumentObj.ListOfChannel[j].ListOfItem[i].ItemLink.InnerText);
            linkButtonForItem.Attributes.Add("onmouseover", "this.style.color = '#006699'");
            linkButtonForItem.Attributes.Add("onmouseout", "this.style.color = '#0000ff'");
            PlaceHolder1.Controls.Add(linkButtonForItem);
            listOfLinkButton.Add(linkButtonForItem);
            PlaceHolder1.Controls.Add(new LiteralControl("<br />"));
            Label labelForItem = new Label();
            labelForItem.ID = "LabelDynamicInPlaceHolder1Id" + i;
            labelForItem.EnableViewState = true;
            labelForItem.ForeColor = Color.DarkGray;
            labelForItem.Text = rssDocumentObj.ListOfChannel[j].ListOfItem[i].ItemDescription.InnerText;
            PlaceHolder1.Controls.Add(labelForItem);
            listOfLabel.Add(labelForItem);
            PlaceHolder1.Controls.Add(new LiteralControl("<br />"));
            Session["ListOfLinkButton"] = listOfLinkButton;
            Session["ListOfLabel"] = listOfLabel;
        }
    }  
}

}

Jarrett Widman · Accepted Answer · 2009-05-11 07:06:08Z

1

You are making assumptions about what aspects of that button is saved in session. Try adding the event to the button again when you restore from session state during your page load.

answered May 11, 2009 at 7:06

Jarrett Widman

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Comments

Toby Speight · Accepted Answer · 2016-07-13 21:07:52Z

0

I got my solution by assigning event-handler to button again after retrieving it from session, but I could not understand why I need to assign it again, when its already assigned in stored session variable.

edited Jul 13, 2016 at 21:07

Toby Speight

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answered May 11, 2009 at 9:01

Maddy.Shik

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1 Comment

Jarrett Widman Over a year ago

If you think about what it would mean to serialize the event handler, which is you'd basically be serializing a pointer to a function, it becomes clear it would probably not be a very beneficial feature, IMO.

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