LINQ: find all checked checkboxes in a GridView

I'm pretty sure you're not going to get any performance improvement from this, but it might make it slightly easier to read:

var checkedIDs = from GridViewRow msgRow in messagesGrid.Rows                 where ((CheckBox)msgRow.FindControl("chkUpdateStatus")).Checked                 select Int32.Parse(messagesGrid.DataKeys[msgRow.RowIndex].Value.ToString());

Again, not sure it makes a difference. Also, why are you converting to a string then to an int? Is there something Convert.ToInt32 can't do for you?

I am not sure if Rows is IEnumerable they may not be, but I am going to assume they are

List<int> checkedIDs = messagesGrid.Rows  .Where<GridViewRow>(i => (CheckBox)i.FindControl("chkUpdateStatus").Checked)  .Select<GridViewRow, int>(i => return int.Parse(messagesGrid.DataKeys[i.RowIndex].Value.ToString()))  .ToList<int>();

I just did this in notepad, there might be a compile error in there. But this is how you could do the same thing with Linq.

I have something similar but I was using it in more than one place so I created an extension method.

public static void ActOnCheckedRows(this GridView gridView, string checkBoxId, Action<IEnumerable<int>> action){   var checkedRows = from GridViewRow msgRow in gridView.Rows                     where ((CheckBox)msgRow.FindControl(checkBoxId)).Checked                     select (int) gridView.DataKeys[msgRow.RowIndex].Value;    action(checkedRows);}

So now I can do something with all the checked rows. The compiler is pretty good at deducing the types but occasionally I need to explicitly declare checkedRows as type IEnumerable.

gvTasksToBill.ActOnCheckedRows("RowLevelCheckBox", checkedRows =>{    foreach (int id in checkedRows)    {       // do something with id    }});