How to remove all selected items from an ObservableCollection

Question

I'm trying to remove all the selected items from the ObservableCollection when a button in a different XAML is clicked, I am unsure on how I can implement it in my system. I'm using this example to guide me - RemoveAll for ObservableCollections?

Below is my code:

Basket.xaml which contains the observablecollection

private static ObservableCollection<Menu.PassedData> passedData = new ObservableCollection<Menu.PassedData>();
    public ObservableCollection<Menu.PassedData> PassedData
    {

        get { return passedData; }
        //get{ passedData = value; }

    bool IsSelected = true;
    }

Listview in Basket

 <ListBox x:Name="listBox" HorizontalAlignment="Left" Height="270" Margin="10,170,0,0" VerticalAlignment="Top" Width="125" IsSynchronizedWithCurrentItem="False" SelectionChanged="listBox_SelectionChanged">
        <ListView Name ="myListView" ItemsSource="{Binding PassedData}" HorizontalAlignment="Left" VerticalAlignment="Center">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="auto"/>
                            <ColumnDefinition Width="auto"/>
                        </Grid.ColumnDefinitions>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="auto"/>
                        </Grid.RowDefinitions>
                        <TextBox Grid.Column="0" Text="{Binding Name}" IsReadOnly="True" FontSize="15" />
                        <TextBox x:Name="quanttextBox" HorizontalAlignment="Left" Height="25" Margin="155,175,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top" Width="95" TextChanged="quanttextBox_TextChanged"/>
                        <!--<TextBox Grid.Column="1" Text="{Binding Value}" /> !-->
                    </Grid>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

    </ListBox>

Confirm.xaml is the page which cotains the button to remove all the items

  public static class ObservableCollectionExtensions
{
    public static void RemoveAll<T>(this ObservableCollection<T> collection,
                                                       Func<T, bool> condition)
    {
        for (int i = collection.Count - 1; i >= 0; i--)
        {
            if (condition(collection[i]))
            {
                collection.RemoveAt(i);
            }
        }
    }
}

The button itself

       private void HyperlinkButton_Click(object sender, RoutedEventArgs e)
    {
        Menu.PassedData.RemoveAll(data => data.IsSelected == true);

        Frame.Navigate(typeof(MainPage));

    }

Menu.PassedData

       public event SelectionChangedEventHandler SelectionChanged;
    public class PassedData
    {
        public string Name { get; set; }
        public double Value { get; set;}

        bool IsSelected = true;

        internal static void RemoveAll(Func<object, bool> p)
        {
            throw new NotImplementedException();
        }
    }

Error

You should have a bool property in Menu.PassedData class to store if it is selected. It will be easy then.You can loop through the items in event handler,check the selected property. If it is true delete that — Archana, Apr 15 '16 at 11:47

score 0 · Answer 1 · answered Apr 15 '16 at 11:47

0

Your Remove statement c.Remove(x => x.c) does not provide the lambda expression you defined in your extension. You should write something like

c.Remove(x => x.c == trueStatement)

answered Apr 15 '16 at 11:47

Wicher Visser

1,513
12
21

Archana · Accepted Answer · 2016-04-15T14:57:23.893

0

You should have a Boolean property in Menu.PassedData called IsSelected. Make that property to true when listview item is selected using SelectionChangedEvent

private void SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            foreach (var item in e.AddedItems)
            {

                (item as Menu.Passed).Selected=true
            }
        }
private void HyperlinkButton_Click(object sender, RoutedEventArgs e)
        {

         PassedData.RemoveAll(data => data.IsSelected == true);

         }





        public class PassedData
        {
            public string Name { get; set; }
            public double Value { get; set;}

            public bool IsSelected{get;set;}


        }

edited Apr 15 '16 at 14:57

answered Apr 15 '16 at 11:57

Archana

3,213
1
15
21

Thanks for the answer, Where should I set the boolean property in the Basket.xaml.cs? and should it be inside the public ObservableCollection? – Joe Goldberg Apr 15 '16 at 13:27
It should be inside Menu.Passed class – Archana Apr 15 '16 at 13:28
Ohh I dont really have a class for that ObservableCollection. If I input class after Public it gives an error of : expected '>' I have updated the question with the current state of my code. – Joe Goldberg Apr 15 '16 at 13:46
Then what is Menu.Passed? – Archana Apr 15 '16 at 13:50
What is the type of item of collection? – Archana Apr 15 '16 at 13:52
Sorry my bad yes it is a class I have set the boolean property inside that class and still nothing. – Joe Goldberg Apr 15 '16 at 13:53
Did you handle Selectionchanged event? What are you getting now? – Archana Apr 15 '16 at 14:10
Are you getting exception? – Archana Apr 15 '16 at 14:11
Yes when I click the button it freezes ands gives that error. Also I dont think I handle Selectionchanged event correctly. Sorry I am new to c# and just trying to get through it. question is updated with error – Joe Goldberg Apr 15 '16 at 14:26
You don't need RemoveAll method which is there inside PassedData. Remove that. It should call ObservableCollectionExtensions class RemoveAll method. I don't know did you write that or not. And make Selecteditem property public with getter setter – Archana Apr 15 '16 at 14:34
Please post the chat discussion link, which I don't have access to, since comments are getting increased – Archana Apr 15 '16 at 14:35
I would but unfortunately stack doesnt let me, I require more point :(. I have done exactly what you said but an error occurs in the button underneath the RemoveAll part because I deleted the automatically created method, It doesnt seem to call the ObservableCollectionExtensions because I set it in the top (Before the Menu Class ) because if I set it within the Menu Class it shows an error saying ' Extension Methods must be defined in a top level static class; ObservableCollectionExtensions is a nested class. – Joe Goldberg Apr 15 '16 at 14:57
Add the separate class file and add this extension class code over there – Archana Apr 15 '16 at 15:00
Ohhh Yes Thankyouuu :) – Joe Goldberg Apr 15 '16 at 19:38

How to remove all selected items from an ObservableCollection

2 Answers2