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 (int i = 0; i < this.Controls.Count; ++i)
{
if (this.Controls[i].Name.Length == 2)
{
this.Controls.Remove(this.Controls[i);
}
}
But it so happens that the code is wrong. I then change it to:
foreach (Control ctr in this.pbBoardImage.Controls)
{
if (ctr.Length == 2)
{
this.Controls.Remove(ctr);
}
}
But it still wasn't correct. I know that the correct way would be:
for (int i = this.Controls.Count - 1; i >= 0; i--)
{
if (this.Controls[i].Name.Length == 2)
{
this.Controls.Remove(this.Controls[i]);
}
}
However it still doesn't feel elegant. I couldn't use List.RemoveAll, since this.Controls wasn't a List. So can I ask for a more elegant way, preferably without using a loop?
From stackoverflow
-
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
withinforeach
- 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.
Marc Gravell : I'd love to know why the downvote...J W : Seems like a good answer to me. I upvoted it.Mitch Wheat : It wasn't me, but it's the correct answer, so +1!
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