CODEWITHSUNDEEP
c#xamarin.formsobservablecollection
Floyd Resler
Floyd Resler

Reputation: 1786

Delete Multiple Items from ObservableCollection

I want to delete multiple items in an ObservableCollection in C#. My code is:

var item = (MoveDataModel)e.SelectedItem;
var answer = await DisplayAlert("Confirmation", "Are you sure you wish to delete " + item.value + "?", "Yes", "No");
        if (answer)
{
    var type = item.type;
    var value = item.value;

    foreach (var listItem in items)
    {
        if ((listItem.value == item.value) || (listItem.location == value && type == "Location"))
        {
            items.Remove(listItem);
            itemCount--;
        }
    }
}

The first iteration works fine. However, it hangs on

foreach (var listItem in items)

on the second pass. I'm not sure how to make it work.

Upvotes: 0

Views: 2907

Answers (2)

Gauthier
Gauthier

Reputation: 1321

Have your own counter, cycle backwards through the list so you wont have to readjust for indexes you removed.

System.Collections.ObjectModel.ObservableCollection<object> list = new System.Collections.ObjectModel.ObservableCollection<object>();
private void RemoveStuff()
{
    var i = list.Count - 1;
    for (; i <= 0; i--)
    {
        // some checks here to make sure this is the time you really want to remove
        list.Remove(i);
    }

}

Upvotes: 1

Jason
Jason

Reputation: 89102

you can't modify a collection while you're iterating over it. Try something like this (I haven't checked the syntax, may need some cleanup)

var removeList = items.Where(x => x.value == value).Where(y => y.type = type).ToList();

foreach(var i in removeList) {
  items.Remove(i);
  itemCount--;
}

Upvotes: 1

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