ASP.NET dynamic Command Button only fires every other time

Question

Similar to this question here ASP.Net Dynamic Command Button Event Not Firing but with a slightly different problem.

Provided below is a (very) condensed version of my code.

    protected void Page_Load(object sender, EventArgs e)
    {
        RenderDataItems();
    }

    private void RenderDataItems()
    {
        pnlDataItems.Controls.Clear()
        DataTable dt = MyClass.GetAllData();

        foreach (DataRow dr in dt.Rows)
        {
            Button b = new Button();
            b.Command += new CommandEventHandler(SelectItem);
            b.CommandArgument = dr["ID"].ToString();
            b.ID = "btnData" + dr["ID"].ToString();

            if (hdnDataListID.Value == dr["ID"].ToString())
            {
                b.Text = "Selected Item";
            }
            else
            {
                b.Text = "Pick This Item";
            }
            pnlDataItems.Controls.Add(b);
        }
    }

    private void SelectItem(object sender, CommandEventArgs e)
    {
        hdnDataListID.Value = e.CommandArgument.ToString();
        RenderDataItems();
    }

    private void EditSelectItem(int id)
    {
        MyClass mc = new MyClass(id);
        hdnDataListID.Value = mc.ID.ToString();
        RenderDataItems();
    }

The method SelectItem is only called by the button controls rendered within the RenderDataItems method. The EditSelectItem is called by a separate control that is created dynamically, but does not require the altering that the buttons in the RenderDataItems method requires.

I've run the debugger and stepped through the code to see what happens. When the page is loaded, the RenderDataItems is called from the PageLoad and populates the panel with all of the buttons having "Pick This Text" (because the HiddenField control's value (hdnDataListID) has not been set).

The first time I click one of the buttons, the RenderDataItems from PageLoad fires, followed by the initial population of the buttons, the HiddenField's value is set to the ID, and the second RenderDataItems call happens from within the SelectItem method. The buttons are cleared, and recreated. The correct button has the "Selected Item" text.

The second time I click one of the buttons, the RenderDataItems from PageLoad fires, followed by the initial population of the buttons, but the SelectItem method never fires.

The third time I click one of the buttons, the same functionality happens as the 1st time. The 4th mimics the 2nd. The 5th mimics the 1st. And so on, and so on.

When using the EditSelectItem method from the controls not contained within the panel (it's a DataSource bound GridView row with buttons that calls this method), it does exactly as I'd expect and properly sets the selected / unselected buttons, with calls to both the RenderDataItems and the EditSelectItem method every time.

Any ideas?

P.S. I've already removed all of my AJAX on this page.

Answer 1

You should give you Button b an ID.