Removing controls in a loop

Question

Yesterday I wrote a piece of code to remove all the controls in a form that fulfills certain criteria. Writing it naively, this is what I come up with.

for (         


        

Answer 1

Not sure why you didn't like this answer... I've highlighted the important RemoveAt; however, as an alternative in .NET 3.5/C# 3.0: LINQ:

        var qry = from Control control in Controls
                  where control.Name.Length == 2
                  select control;

        foreach(var control in qry.ToList()) {
            Controls.Remove(control);
        }

---

(original)

You can't Remove within foreach - it breaks the iterator. A common approach here is to iterate backwards:

for (int i = this.Controls.Count - 1; i >= 0; i--) {
    if (this.Controls[i].Name.Length == 2) {
        this.Controls.RemoveAt(i); // <=========== *** RemoveAt
    }
}

This avoids the "off by one" issues, etc.