Can't locate checkbox in webform

Question

I'm trying to locate a checkbox on my webform, but am not able to? It's always set to NULL? I have tried different approaches (the i is set via a FOR loop, I'm using a Masterpage as well):

CheckBox cb = (CheckBox)this.FindControl("ctl00_ContentPlaceHolder1_sa" + i.ToString());

CheckBox cb = (CheckBox)Page.FindControl("ctl00_ContentPlaceHolder1_sa" + i.ToString());

CheckBox cb = (CheckBox)Parent.FindControl("ctl00_ContentPlaceHolder1_sa" + i.ToString());

... as well as...

CheckBox cb = (CheckBox)this.FindControl("sa" + i.ToString());

CheckBox cb = (CheckBox)Page.FindControl("sa" + i.ToString());

CheckBox cb = (CheckBox)Parent.FindControl("sa" + i.ToString());

Any ideas?

Can you show how you made the checkbox? – BugFinder Aug 13 '15 at 06:33 — BugFinder, Aug 13 '15 at 06:33

score 1 · Answer 1 · answered Aug 13 '15 at 06:16

1

Findcontrol works with the id, not the clientside generated id (as your first code block looks like).

Use Findcontrol on the parent object (not always necessary if I'm correct). If the checkbox is on the page body, use Page.FindControl, or this.FindControl. When it's in a listview for example, use it in the proper event.

answered Aug 13 '15 at 06:16

Erik

119
6

Made the changes, keep getting the same error. Very strange. – Robert Benedetto Aug 13 '15 at 06:25

score 1 · Answer 2 · edited Mar 19 '18 at 11:16

1

You can try this code:

foreach ( Control c in Panel1.Controls )
{
    CheckBox cb = c as CheckBox;
    if(cb!=null)
    {

    }
}

Here Panel1 contains all the checkbox..thank you.

edited Mar 19 '18 at 11:16

answered Aug 13 '15 at 06:17

Linda Manu

43
10

score 1 · Accepted Answer · answered Aug 13 '15 at 06:28

1

I placed the checkboxes inside a panel, and was able to access them with Panel1.FindControl as per @linuser.

Feels like a quickfix but it works.

answered Aug 13 '15 at 06:28

Robert Benedetto

1,590
2
29
52

Can't locate checkbox in webform

3 Answers3