Dynamically create multiple ImageButton controls and wire-up Click event

Question

I'm pretty new to ASP.NET. Please forgive me for my knowledge :) Assuming I want to create 4 imagebuttons. If I click on any imagebutton, it will move me to another page with different STT (<- just a name). Here's my code:

    for (int i= 0; i< 4; i++)
            {
                ImageButton image = new ImageButton();
                image.Click += (s, args) =>
                    {
                        Response.Redirect("~/Showroom.aspx?STT=" + (i));
                    };
               //other things to do
            }

Now the problem is that when I click on any imagebutton. I'll be redirected to Showroom.aspx with STT = 4 (which is i after the loop). How can I be redirected to the page with desired STT.

EDIT: Just to clarify. What I want is Clicking on imagebutton 1 will move me to Showroom.aspx with STT = 0. Imagebutton 2 will move me to the page with STT=1 and so on.

As I said. It always redirect me to Showroom.aspx with STT = 4 (which is i after the loop) — Androidizing
– Androidizing, Commented Sep 23, 2014 at 17:45

Win · Accepted Answer · 2014-09-23 18:06:41Z

1

Problem

"~/Showroom.aspx?STT=" + (i) means it captures the variable i rather than its value at the time of delegates creation.

Solution

Create url outside of delegate.

for (int i = 0; i < 3; i++)
{
    string url = string.Format("~/Showroom.aspx?STT={0}", i);
    var image = new ImageButton();
    image.Click += (s, args) => Response.Redirect(url);
}

answered Sep 23, 2014 at 18:06

Win

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Comments

Romano Zumbé · Accepted Answer · 2017-07-03 13:21:57Z

1

You need to copy i to a local variable. Or as the other Answer suggests, build your URL before its used in your lambda expression.

            int x = i;
            image.Click += (s, args) =>
            {
                Response.Redirect("~/Showroom.aspx?STT=" + (x));
            };

edited Jul 3, 2017 at 13:21

Romano Zumbé

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answered Sep 23, 2014 at 18:07

cbeuker

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1 Comment

Androidizing Over a year ago

Yeah! It works. I didn't think of storing it as a local variable :)

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