Add List box to List<ListBox> to pass to foreach loop ASP.NET

Question

Hi I'm trying to create a list of ListBox's in ASP.NET so that I can then iterate it to test if it has been selected.

    List<string> con = new List<string>();
    List<ListBox> lb = new List<ListBox>();
    foreach (Control c in _pH_Outer_MainCri.Controls)
    {
        if (c is ListBox)
        {
            con.Add(c.ID.ToString());
            lb.Add(c.??);
        }
    }

I'm getting caught up on that last part. Basically then I can

foreach(ListBox a in lb)
    {
        if(a.TestSelection() == true )
        {
            BuildQuery(a);
        }
    }

Thanks in advance for the help ...

What exactly is the issue? Are you getting an error or is it not behaving as expected? What were you expecting it to do? — Alastair Pitts
– Alastair Pitts, Commented May 17, 2011 at 0:21

Bala R · Accepted Answer · 2011-05-17 00:22:49Z

2

If you are adding all listboxes then you would want

lb.Add((ListBox)c);

answered May 17, 2011 at 0:22

Bala R

109k23 gold badges203 silver badges212 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Jacob · Accepted Answer · 2011-05-17 00:33:01Z

1

You can avoid placing the controls in a list by using LINQ, like this:

var listboxen =
    from control in _pH_Outer_MainCri.Controls
    where control is ListBox
    select control as ListBox;

You can then foreach through the list boxes without having to build an intermediate collection.

answered May 17, 2011 at 0:33

Jacob

79k24 gold badges159 silver badges245 bronze badges

1 Comment

bumble_bee_tuna Over a year ago

I love linq its like the swiss army knife of C#. I like this I thnk it is very elegant, however I can't seem t get it to work "Error 2 Could not find an implementation of the query pattern for source type 'System.Web.UI.ControlCollection'. 'Where' not found. Consider explicitly specifying the type of the range variable 'control"

skaz · Accepted Answer · 2011-05-17 00:28:31Z

0

When I get overwhelmed, I often find it helpful to take a step back and think about my structures:

List<ListBox> lb - This is a list and each member in the list is of a type ListBox.

In your loop, you want to pull out all of the listboxes, so when you have: if (c is ListBox) { you know that c is already of the type listbox, which is the same type lb is storing. It is simply a matter of adding c to your collection in lb with lb.Add(c);

Separately - do you really need to store these items only to loop through them again and call BuildQuery? Looping through, putting them in a list, and then looping through that collection again may be extra overhead depending on what you are doing.

answered May 17, 2011 at 0:28

skaz

22.8k20 gold badges73 silver badges99 bronze badges

1 Comment

bumble_bee_tuna Over a year ago

This is very true, I've spent so much time building the layout of the controls that I think I need to step back a little. I'm in design mode not functionality mode lol ...

Collectives™ on Stack Overflow

Add List box to List<ListBox> to pass to foreach loop ASP.NET

3 Answers 3

Comments

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related