FormView.FindControl() returns null until DataBind()

Question

Why method FindControl() returns null on FormView until call DataBind().

After that it returns everything correctly?

What workaround are there?

Call DataBind() before first call of FindControl() ?

score 5 · Accepted Answer · answered Jan 31 '10 at 11:51

5

Either explicitly call DataBind(), or place your code in the DataBound event of the FormView.

answered Jan 31 '10 at 11:51

devio

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score 3 · Answer 2 · answered Jan 31 '10 at 11:36

3

How would a FormView have any information about its content before it has any data to build it upon?

So I guess you already answered your own question, you will have to DataBind() before.

answered Jan 31 '10 at 11:36

herzmeister

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How is one to access the control in DataBound() function, if it's not available until after data binding has occurred? I am within the OnDataBound callback, and yet FindControl returns null. – Barry Sep 20 '17 at 21:04

score 0 · Answer 3 · answered Jul 30 '14 at 00:51

It is very odd. Did not work for me just calling DataBind(). I had to create a new List, add an item, set as datasource, then databin.

List<Item> dummyList = new List<Item>();
dummyList.Add(new Item());
formview.DataSource = dummyList;
formview.DataBind();

score 0 · Answer 4 · edited May 12 '16 at 13:18

what I experienced is this,

System.Web.UI.HtmlControls.HtmlImage bookmarkload = sessionDetail.FindControl("bookmarkimage") as System.Web.UI.HtmlControls.HtmlImage;

returned null.

So, I did this:

 protected void sessionDetail_DataBound(object sender, EventArgs e)
        {
            LoadBookmarkImage();
        }
  private void LoadBookmarkImage()
        {
            //if (_swapDetails != null)
            //{             
                try
                {
                    _currnetSession = new SessionBL(_user);

                    List<SessionVO> _tmp = null;
                    string sample = Convert.ToString(Page.RouteData.Values["sessionCode"]);
                    if (Session["Prefernce"] != null)
                    {
                        _tmp = (List<SessionVO>)Session["Prefernce"];
                    }
                    if (_tmp != null && _tmp.Count > 0)
                    {
                        _tmp = _tmp.Where(p => p.SessionCode == sample).ToList();
                    }

                    //_currentFavorite.SessionD = _swapDetails[0];
                    _currentFavorite.SessionD = _tmp[0];

                    List<FavoriteVO> _swapList = _user.ViewFavoriteONID(_currentFavorite.SessionD.SessionID);

                    if (_swapList != null && _swapList.Count > 0)
                    {
                        //access javascript counter variable
                        ScriptManager.RegisterStartupScript(this, this.GetType(), "", "counter=1;", true);
                        System.Web.UI.HtmlControls.HtmlImage bookmarkload = sessionDetail.FindControl("bookmarkimage") as System.Web.UI.HtmlControls.HtmlImage;
                        bookmarkload.Src = "/Images/heart-checked.png";
                    }
                }
                catch (Exception ex)
                {
                    labelinfo.Visible = true;
                    labelinfo.InnerHtml = ex.Message;
                    labelinfo.Attributes["class"] = "centering text-center text-danger";
                }
            //}
        }

Alexander · Answer 5 · 2010-12-07T15:00:29.717

0

It has nothing to do with BINDING. One is looking for SERVER CONTROL, not for ITS BOUND DATA. SO - control should be available via FindControl. The reason is somewhere else...

edited Dec 07 '10 at 15:00

answered Nov 13 '10 at 02:21

Alexander

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This is well-known behavior of FormView.NamingContainer, indeed. – abatishchev Nov 13 '10 at 06:31

FormView.FindControl() returns null until DataBind()

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