Question

当我点击不同XAML中的按钮时，我试图从ObservableCollection中删除所有选定的项目，我不确定如何在我的系统中实现它。我使用此示例来指导我 - RemoveAll for ObservableCollections?

以下是我的代码：

Basket.xaml，其中包含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;
    }

购物篮中的Listview

 <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>

确认.xaml是包含删除所有项目的按钮的页面

  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);
            }
        }
    }
}

按钮本身

       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();
        }
    }

错误

Answer 1

您的删除语句c.Remove(x => x.c == trueStatement)未提供您在扩展程序中定义的lambda表达式。你应该写点像

function attachEvent(element, event, callbackFunction) {
  if(element.addEventListener)  {
    element.addEventListener(event, function(){
      callbackFunction(this.getAttribute("src"));
    }, false);
  }
}

//start the function 
attachEvent(".Dicon", "click", handler);

function handler(){
console.log("stop");
}

Answer 2

您应该在Menu.PassedData中使用名为IsSelected的布尔属性。使用SelectionChangedEvent

选择listview项时，将该属性设置为true

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;}


        }

如何从ObservableCollection中删除所有选定的项目

2 个答案: