asp.net object reference not set error

Question

I am trying to find the label control from aspx page.

Label labelmessageupdate;
          labelmessageupdate = (System.Web.UI.WebControls.Label )FindControl("updateMessage1");

if i set labelmessageupdate.Text ="something"

it returns object reference exception.

and the label control is within the update panel could that be the problem.

Answer 1

Just check for null. Always check null condition so that it doesn't end up showing Object Reference error.

if (labelmessageupdate != null)
{
     labelmessageupdate.Text ="something"
}

Answer 2

I think its not able to find the label control you specified

if(FindControl("updateMessage1") is Label)
{
    labelmessageupdate = FindControl("updateMessage1") as Label;
    labelmessageupdate.Text="This shoould work if available";
}

Answer 3

Try this, and the control your trying to find could be in a another user control.

To use

Label updateMessage = FindChildControl<Label>(base.Page, "updateMessage1");
if (updateMessage!=null) 
{
   updateMessage.Text = "new text";
}

/// <summary>     
/// Similar to Control.FindControl, but recurses through child controls.
/// Assumes that startingControl is NOT the control you are searching for.
/// </summary>
public static T FindChildControl<T>(Control startingControl, string id) where T : Control
{
    T found = null;

    foreach (Control activeControl in startingControl.Controls)
    {
        found = activeControl as T;

        if (found == null || (string.Compare(id, found.ID, true) != 0))
        {
            found = FindChildControl<T>(activeControl, id);
        }

        if (found != null)
        {
            break;
        }
    }

    return found;
}