WPF ListBox滚动到底部 [英] WPF ListBox Scroll to the bottom

问题描述

我将ObservableCollection用作listBox组件的ItemSource:

I am using ObservableCollection as an ItemSource for my listBox component:

但是控件的行为对我而言是不合适的.我已向下滚动到收藏夹中第一次出现的问题，但没有最后一个出现.

But the behavior of the control is not proper as for me. The matter I have scroll down to ths first occurence in my collection, but not last.

示例列表为:1,1,2,3,4,5,6,7,8,9,11,22,33,1

The sample list is: 1,1,2,3,4,5,6,7,8,9,11,22,33,1

当您输入最后一个1时，组件将向上滚动到第一个1 :).这不是我想要的.

When you enetr last 1 you component scroll up to first 1 :). This not what I am wating for.

请告知.这里是组件代码:

Please advise. Here a code of component:

public class MyListBox : ListBox
{
    protected override void OnItemsChanged(System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
    {
        base.OnItemsChanged(e);
        if (Items.Count > 0)
        {
            var item = Items[Items.Count - 1];
            UpdateLayout();
            ScrollIntoView(item);
            UpdateLayout();
        }
    }

}

推荐答案

抱歉，它必须是一个类，因为List或OC会真正进行值比较.因此，您需要使相同的值唯一.我测试了一下，它可以工作.

Sorry but it needs to be a class as a List or OC is going to really do a value comparison. So you need to make identical values unique. I test this out and it works.

     <StackPanel Orientation="Vertical" >
        <ListBox x:Name="lbStringList" ItemsSource="{Binding Path=UniqueStringList}" DisplayMemberPath="Str" Height="60" VerticalAlignment="Top"/>
        <Button Click="Button_Click" Content="56" />
     </StackPanel>


    private List<UniqueString> uniqueStringList = new List<UniqueString>() 
            {                   
                new UniqueString("zero",0),
                new UniqueString("one",1),
                new UniqueString("two",2),
                new UniqueString("three",3),
                new UniqueString("four",4),
                new UniqueString("five",5),
                new UniqueString("six",6),
                new UniqueString("seven",7),
                new UniqueString("zero",8)
            }; 

    public MainWindow()
    {
        InitializeComponent();

    }
    public List<string> StringList { get { return new List<string>() { "one", "two", "three", "four", "five", "one" }; } }
    public List<UniqueString> UniqueStringList 
    { 
        get 
        {
            return uniqueStringList;
        } 
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        System.Diagnostics.Debug.WriteLine(sender.GetHashCode());
        lbStringList.ScrollIntoView(lbStringList.Items[8]);

    }
    public class UniqueString
    {
        private Int32 id;
        public string Str { get; private set; }
        public override bool Equals(object obj)
        {
            UniqueString item = (UniqueString)obj;
            return item.id == id;
        }
        public override int GetHashCode()
        {
            return id;
        }

        public UniqueString(string str, Int32 _id) { Str = str; id = _id; }
    }

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