在我的应用程序中，我有一个ListBox项目。该应用程序是用WPF编写的。
如何自动滚动到最后添加的项目？我希望在添加新项目时将ScrollViewer移动到列表的末尾。
是否有像ItemsChanged这样的事件？
（我不想使用SelectionChanged事件）
答案 0 :(得分：35)
试试这个：
lstBox.SelectedIndex = lstBox.Items.Count -1;
lstBox.ScrollIntoView(lstBox.SelectedItem) ;
在您的MainWindow中，这将选择并关注列表中的最后一项！
答案 1 :(得分：30)
最简单的方法：
if (VisualTreeHelper.GetChildrenCount(listView) > 0)
{
Border border = (Border)VisualTreeHelper.GetChild(listView, 0);
ScrollViewer scrollViewer = (ScrollViewer)VisualTreeHelper.GetChild(border, 0);
scrollViewer.ScrollToBottom();
}
它始终适用于ListView和ListBox控件。将此代码附加到listView.Items.SourceCollection.CollectionChanged事件，您将拥有完全自动的自动滚动行为。
答案 2 :(得分：28)
请注意，listBox.ScrollIntoView(listBox.Items[listBox.Items.Count - 1]);仅在您没有重复项目时才有效。如果您有相同内容的项目，则向下滚动到第一个查找。
以下是我找到的解决方案：
ListBoxAutomationPeer svAutomation = (ListBoxAutomationPeer)ScrollViewerAutomationPeer.CreatePeerForElement(myListBox);
IScrollProvider scrollInterface = (IScrollProvider)svAutomation.GetPattern(PatternInterface.Scroll);
System.Windows.Automation.ScrollAmount scrollVertical = System.Windows.Automation.ScrollAmount.LargeIncrement;
System.Windows.Automation.ScrollAmount scrollHorizontal = System.Windows.Automation.ScrollAmount.NoAmount;
//If the vertical scroller is not available, the operation cannot be performed, which will raise an exception.
if ( scrollInterface.VerticallyScrollable )
scrollInterface.Scroll(scrollHorizontal, scrollVertical);
答案 3 :(得分：20)
最好的解决方案是在ListBox控件中使用ItemCollection对象 此系列专为内容观众设计。它有一个预定义的方法来选择最后一项并保持光标位置参考....
myListBox.Items.MoveCurrentToLast();
myListBox.ScrollIntoView(myListBox.Items.CurrentItem);
答案 4 :(得分：5)
与目前提供的方法略有不同。
您可以使用ScrollViewer ScrollChanged事件并关注ScrollViewer变大的内容。
private void ListBox_OnLoaded(object sender, RoutedEventArgs e)
{
var listBox = (ListBox) sender;
var scrollViewer = FindScrollViewer(listBox);
if (scrollViewer != null)
{
scrollViewer.ScrollChanged += (o, args) =>
{
if (args.ExtentHeightChange > 0)
scrollViewer.ScrollToBottom();
};
}
}
这可以避免绑定到ListBox ItemsSource更改的一些问题。
也可以在不假设ScrollViewer使用默认控件模板的情况下找到ListBox。
// Search for ScrollViewer, breadth-first
private static ScrollViewer FindScrollViewer(DependencyObject root)
{
var queue = new Queue<DependencyObject>(new[] {root});
do
{
var item = queue.Dequeue();
if (item is ScrollViewer)
return (ScrollViewer) item;
for (var i = 0; i < VisualTreeHelper.GetChildrenCount(item); i++)
queue.Enqueue(VisualTreeHelper.GetChild(item, i));
} while (queue.Count > 0);
return null;
}
然后将其附加到ListBox Loaded事件：
<ListBox Loaded="ListBox_OnLoaded" />
这可以很容易地修改为附加属性，以使其更具通用性。
答案 5 :(得分：4)
listBox.ScrollIntoView（listBox.Items [listBox.Items.Count - 1]）;
答案 6 :(得分：2)
这里的答案都没有满足我的需要。因此，我编写了自己的行为，自动滚动项目控件，并在用户向上滚动时暂停自动滚动，并在用户向下滚动到底部时恢复自动滚动。
/// <summary>
/// This will auto scroll a list view to the bottom as items are added.
/// Automatically suspends if the user scrolls up, and recommences when
/// the user scrolls to the end.
/// </summary>
/// <example>
/// <ListView sf:AutoScrollToBottomBehavior="{Binding viewModelAutoScrollFlag}" />
/// </example>
public class AutoScrollToBottomBehavior
{
/// <summary>
/// Enumerated type to keep track of the current auto scroll status
/// </summary>
public enum StatusType
{
NotAutoScrollingToBottom,
AutoScrollingToBottom,
AutoScrollingToBottomButSuppressed
}
public static StatusType GetAutoScrollToBottomStatus(DependencyObject obj)
{
return (StatusType)obj.GetValue(AutoScrollToBottomStatusProperty);
}
public static void SetAutoScrollToBottomStatus(DependencyObject obj, StatusType value)
{
obj.SetValue(AutoScrollToBottomStatusProperty, value);
}
// Using a DependencyProperty as the backing store for AutoScrollToBottomStatus. This enables animation, styling, binding, etc...
public static readonly DependencyProperty AutoScrollToBottomStatusProperty =
DependencyProperty.RegisterAttached(
"AutoScrollToBottomStatus",
typeof(StatusType),
typeof(AutoScrollToBottomBehavior),
new PropertyMetadata(StatusType.NotAutoScrollingToBottom, (s, e) =>
{
if (s is DependencyObject viewer && e.NewValue is StatusType autoScrollToBottomStatus)
{
// Set the AutoScrollToBottom property to mirror this one
bool? autoScrollToBottom = autoScrollToBottomStatus switch
{
StatusType.AutoScrollingToBottom => true,
StatusType.NotAutoScrollingToBottom => false,
StatusType.AutoScrollingToBottomButSuppressed => false,
_ => null
};
if (autoScrollToBottom.HasValue)
{
SetAutoScrollToBottom(viewer, autoScrollToBottom.Value);
}
// Only hook/unhook for cases below, not when suspended
switch(autoScrollToBottomStatus)
{
case StatusType.AutoScrollingToBottom:
HookViewer(viewer);
break;
case StatusType.NotAutoScrollingToBottom:
UnhookViewer(viewer);
break;
}
}
}));
public static bool GetAutoScrollToBottom(DependencyObject obj)
{
return (bool)obj.GetValue(AutoScrollToBottomProperty);
}
public static void SetAutoScrollToBottom(DependencyObject obj, bool value)
{
obj.SetValue(AutoScrollToBottomProperty, value);
}
// Using a DependencyProperty as the backing store for AutoScrollToBottom. This enables animation, styling, binding, etc...
public static readonly DependencyProperty AutoScrollToBottomProperty =
DependencyProperty.RegisterAttached(
"AutoScrollToBottom",
typeof(bool),
typeof(AutoScrollToBottomBehavior),
new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, (s, e) =>
{
if (s is DependencyObject viewer && e.NewValue is bool autoScrollToBottom)
{
// Set the AutoScrollToBottomStatus property to mirror this one
if (autoScrollToBottom)
{
SetAutoScrollToBottomStatus(viewer, StatusType.AutoScrollingToBottom);
}
else if (GetAutoScrollToBottomStatus(viewer) == StatusType.AutoScrollingToBottom)
{
SetAutoScrollToBottomStatus(viewer, StatusType.NotAutoScrollingToBottom);
}
// No change if autoScrollToBottom = false && viewer.AutoScrollToBottomStatus = AutoScrollToBottomStatusType.AutoScrollingToBottomButSuppressed;
}
}));
private static Action GetUnhookAction(DependencyObject obj)
{
return (Action)obj.GetValue(UnhookActionProperty);
}
private static void SetUnhookAction(DependencyObject obj, Action value)
{
obj.SetValue(UnhookActionProperty, value);
}
// Using a DependencyProperty as the backing store for MyProperty. This enables animation, styling, binding, etc...
private static readonly DependencyProperty UnhookActionProperty =
DependencyProperty.RegisterAttached("UnhookAction", typeof(Action), typeof(AutoScrollToBottomBehavior), new PropertyMetadata(null));
private static void ItemsControl_Loaded(object sender, RoutedEventArgs e)
{
if (sender is ItemsControl itemsControl)
{
itemsControl.Loaded -= ItemsControl_Loaded;
HookViewer(itemsControl);
}
}
private static void HookViewer(DependencyObject viewer)
{
if (viewer is ItemsControl itemsControl)
{
// If this is triggered the xaml setup then the control won't be loaded yet,
// and so won't have a visual tree which we need to get the scrollviewer,
// so defer this hooking until the items control is loaded.
if (!itemsControl.IsLoaded)
{
itemsControl.Loaded += ItemsControl_Loaded;
return;
}
if (FindScrollViewer(viewer) is ScrollViewer scrollViewer)
{
scrollViewer.ScrollToBottom();
// Scroll to bottom when the item count changes
NotifyCollectionChangedEventHandler itemsCollectionChangedHandler = (s, e) =>
{
if (GetAutoScrollToBottom(viewer))
{
scrollViewer.ScrollToBottom();
}
};
((INotifyCollectionChanged)itemsControl.Items).CollectionChanged += itemsCollectionChangedHandler;
ScrollChangedEventHandler scrollChangedEventHandler = (s, e) =>
{
bool userScrolledToBottom = (e.VerticalOffset + e.ViewportHeight) > (e.ExtentHeight - 1.0);
bool userScrolledUp = e.VerticalChange < 0;
// Check if auto scrolling should be suppressed
if (userScrolledUp && !userScrolledToBottom)
{
if (GetAutoScrollToBottomStatus(viewer) == StatusType.AutoScrollingToBottom)
{
SetAutoScrollToBottomStatus(viewer, StatusType.AutoScrollingToBottomButSuppressed);
}
}
// Check if auto scrolling should be unsuppressed
if (userScrolledToBottom)
{
if (GetAutoScrollToBottomStatus(viewer) == StatusType.AutoScrollingToBottomButSuppressed)
{
SetAutoScrollToBottomStatus(viewer, StatusType.AutoScrollingToBottom);
}
}
};
scrollViewer.ScrollChanged += scrollChangedEventHandler;
Action unhookAction = () =>
{
((INotifyCollectionChanged)itemsControl.Items).CollectionChanged -= itemsCollectionChangedHandler;
scrollViewer.ScrollChanged -= scrollChangedEventHandler;
};
SetUnhookAction(viewer, unhookAction);
}
}
}
/// <summary>
/// Unsubscribes the event listeners on the ItemsControl and ScrollViewer
/// </summary>
/// <param name="viewer"></param>
private static void UnhookViewer(DependencyObject viewer)
{
var unhookAction = GetUnhookAction(viewer);
SetUnhookAction(viewer, null);
unhookAction?.Invoke();
}
/// <summary>
/// A recursive function that drills down a visual tree until a ScrollViewer is found.
/// </summary>
/// <param name="viewer"></param>
/// <returns></returns>
private static ScrollViewer FindScrollViewer(DependencyObject viewer)
{
if (viewer is ScrollViewer scrollViewer)
return scrollViewer;
return Enumerable.Range(0, VisualTreeHelper.GetChildrenCount(viewer))
.Select(i => FindScrollViewer(VisualTreeHelper.GetChild(viewer, i)))
.Where(child => child != null)
.FirstOrDefault();
}
}
答案 7 :(得分：1)
对我来说，最简单的工作方式是这样的：（无绑定）
private void WriteMessage(string message, Brush color, ListView lv)
{
Dispatcher.BeginInvoke(new Action(delegate
{
ListViewItem ls = new ListViewItem
{
Foreground = color,
Content = message
};
lv.Items.Add(ls);
lv.ScrollIntoView(lv.Items[lv.Items.Count - 1]);
}));
}
无需创建类或更改xaml，只需使用此方法编写消息，它就会自动滚动。
仅拨打电话
myLv.Items.Add(ls);
myLv.ScrollIntoView(lv.Items[lv.Items.Count - 1]);
例如，不要为我工作。
答案 8 :(得分：0)
您可以尝试使用ListBox.ScrollIntoView()方法，但在某些情况下会有problems ...
以下是Tamir Khason的一个例子：Auto scroll ListBox in WPF
答案 9 :(得分：0)
实现自动滚动的最简单方法是挂上 CollectionChanged 事件。只需将该功能添加到从 ListBox 控件派生的自定义类中即可：
using System.Collections.Specialized;
using System.Windows.Controls;
using System.Windows.Media;
namespace YourProgram.CustomControls
{
public class AutoScrollListBox : ListBox
{
public AutoScrollListBox()
{
if (Items != null)
{
// Hook to the CollectionChanged event of your ObservableCollection
((INotifyCollectionChanged)Items).CollectionChanged += CollectionChange;
}
}
// Is called whenever the item collection changes
private void CollectionChange(object sender, NotifyCollectionChangedEventArgs e)
{
if (Items.Count > 0)
{
// Get the ScrollViewer object from the ListBox control
Border border = (Border)VisualTreeHelper.GetChild(this, 0);
ScrollViewer SV = (ScrollViewer)VisualTreeHelper.GetChild(border, 0);
// Scroll to bottom
SV.ScrollToBottom();
}
}
}
}
将自定义控件的名称空间添加到WPF窗口，并使用自定义ListBox控件：
<Window x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:YourProgram"
xmlns:cc="clr-namespace:YourProgram.CustomControls"
mc:Ignorable="d"
d:DesignHeight="450" d:DesignWidth="800">
<cc:AutoScrollListBox ItemsSource="{Binding YourObservableCollection}"/>
</Window>
答案 10 :(得分：0)
这是 100% 对我有用的方法。
初始化部分：
private ObservableCollection<ActionLogData> LogListBind = new ObservableCollection<ActionLogData>();
LogList.ItemsSource = LogListBind;
LogListBind.CollectionChanged += this.OnCollectionChanged;
委托绑定到我的 ObservableCollection 的 CollectionChanged，用作我的 ListView 的项目源：
private void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (VisualTreeHelper.GetChildrenCount(LogList) > 0)
{
Decorator border = VisualTreeHelper.GetChild(LogList, 0) as Decorator;
ScrollViewer scrollViewer = border.Child as ScrollViewer;
scrollViewer.ScrollToBottom();
}
}
此解决方案基于 @mateusz-myślak 解决方案，但我做了一些修复和简化。