Fire server event from client

Question

I am having trouble with the Asp.net page life cycle. I am trying to create a custom menu using HtmlTextWriter with an asp.net LinkButton to fire a server event. I can not get the server event to fire and I get the 'object reference not set to instance of object' when I click my linkbutton. Here is some code.

protected string CreateModuleMenu()
        {
            var modules = ModuleManager.GetModulesByDeveloperId(Developer.DeveloperID);
            StringWriter sw = new StringWriter();
            ClientScriptManager cs = Page.ClientScript;
            using (HtmlTextWriter writer = new HtmlTextWriter(sw))
            {
                foreach (var module in modules)
                {
                    writer.RenderBeginTag(HtmlTextWriterTag.Li);
                    writer.RenderBeginTag(HtmlTextWriterTag.Dl);
                    writer.RenderBeginTag(HtmlTextWriterTag.Dt);
                    writer.Write(module.Name);
                    var files = ModuleManager.GetModuleFilesByModuleId(module.ModuleID);
                    foreach (var file in files)
                    {
                        writer.RenderBeginTag(HtmlTextWriterTag.Dd);
                        LinkButton lb = new LinkButton();
                        lb.ID = "mc" + file.ModuleFileID;
                        lb.Attributes.Add("onclick", cs.GetPostBackEventReference(lb, "LoadControl_Clk"));
                        lb.Text = file.Name;
                        Page.RegisterRequiresRaiseEvent(lb);
                        lb.RenderControl(writer);
                        writer.RenderEndTag();
                    }
                    writer.RenderEndTag();
                    writer.RenderEndTag();
                    writer.RenderEndTag();
                }
            }
            return sw.ToString();

Here is my click event:

protected void LoadControl_Clk(object sender, EventArgs e)
        {

            Response.Write("Hello World");
        }

Finally here is what I have in the Page_Load event. Note: I tried moving this around to PreRender, PreInt, etc.

protected void Page_Load(object sender, EventArgs e)
{   
    LiteralControl lit = new LiteralControl();
        lit.Text = CreateModuleMenu();
        phModuleMenu.Controls.Add(lit);
        if (DefaultModuleFile == null)
            Response.Write("Error.");
        else
        {
            Control ctrl = LoadControl(DefaultModuleFile.Src);
            phAdminModules.Controls.Add(ctrl);
        }
}

Lost. Thanks.

score 0 · Accepted Answer · answered Nov 09 '10 at 20:43

0

Perhaps you need to only load the control in Page_Load on the first time the page is called, that is, if !IsPostBack.

If you load the control on every page load, you will lose the event being fired.

answered Nov 09 '10 at 20:43

DOK

32,337
7
60
92

That always gets me. Inded, if I only call that method on first page_load my event can fire. However, because my html controls are created in code behind they have be loaded on every page load. This is kind of where I started. I can't seem to find the right point in time to load my server controls in the middle of my html string controls. – trevorc Nov 09 '10 at 20:56

Fire server event from client

1 Answers1