如何将ListBox.Items用作列表的Itemsource <String>

Question

I have a ListBox . I also have a list in code behind. I want to get all the items from the listbox as the source of my list .

I tried this way:

<listBox x:Name="MyList" .../>

list<string> feed = new list<string>();

//to get the source
var feed = MyList.Items.Cast<string>().ToList();

but It's throwing an Exception: System.InvalidCastException

what to do?

Answer 1

You are getting the error because your list isn't made of strings! Try to get the string representation instead.

List<string> feed = MyList.Items.Cast<object>()
    .Select(o => o.ToString()).ToList();

Answer 2

list<T> feed = new list<T>();
var feed = MyList.Items.Cast<T>().ToList();

This is the correct way. But, see the type of items you have in your ListBox. They may not be string type That's why you are getting this error. You may not have items with the type string . Replace T with that type in your ListBox. Or fix your ListBox to have items with the type string .

Answer 3

I think Sam's answer is correct. If the ItemsSource of your ListBox is string collection, then casting them to string should not be a problem.

        MyList.ItemsSource = new List<string>
        {
            "one","two","three"
        };
        List<string> feed = MyList.Items.Cast<string>().ToList();

But if the ItemsSource of your ListBox is other than string collection, suppose MyClass collection

    class MyClass
    {
        public string MyProperty { get; set; }
        public override string ToString()
        {
            return this.MyProperty;
        }
    }

Then you have to cast it in appropriate type and select desired property.

        MyList.ItemsSource = new List<MyClass>
        {
            new MyClass {MyProperty ="one"},
            new MyClass {MyProperty ="two"},
            new MyClass {MyProperty ="three"},
        };
        List<string> feed = MyList.Items.Cast<MyClass>().Select(c => c.MyProperty).ToList();

But to answer your question correctly we need to know about the ItemsSource of your ListBox.

Answer 4

You know in wpf you have Listbox has ListboxItem and you have to cash you item to ListboxItem first. And after that. You push the listboxItem.Content to your List<string> list = new List<string>(); foreach (var item in this.MyList.Items) { ListBoxItem castItem = item as ListBoxItem; list.Add(castItem.Content.ToString()); } List<string> list = new List<string>(); foreach (var item in this.MyList.Items) { ListBoxItem castItem = item as ListBoxItem; list.Add(castItem.Content.ToString()); }

Here you can try