C# 如何以编程方式选择WPF树视图中的项目?
如何以编程方式在WPFC# 如何以编程方式选择WPF树视图中的项目?,c#,.net,wpf,treeview,itemscontrol,C#,.net,Wpf,Treeview,Itemscontrol,如何以编程方式在WPFTreeView中选择项目?ItemsControl模型似乎阻止了它。由于一些奇怪的原因,这是一个真正的难题,您必须使用ContainerFromItem获取容器,然后调用select方法 // selectedItemObject is not a TreeViewItem, but an item from the collection that // populated the TreeView. var tvi = treeView.ItemContaine
TreeView
中选择项目?ItemsControl
模型似乎阻止了它。由于一些奇怪的原因,这是一个真正的难题,您必须使用ContainerFromItem获取容器,然后调用select方法
// selectedItemObject is not a TreeViewItem, but an item from the collection that
// populated the TreeView.
var tvi = treeView.ItemContainerGenerator.ContainerFromItem(selectedItemObject)
as TreeViewItem;
if (tvi != null)
{
tvi.IsSelected = true;
}
曾经有一篇关于如何做的博客文章,但是现在链接已经死了。你需要获得
树视图项
,然后将IsSelected
设置为true
这并不像看起来那么简单,Steven提供的链接在2008年发布了一个解决方案,它可能仍然可以工作,但不能处理虚拟化的TreeView。此外,该条评论中还提到了许多其他问题。没有冒犯,但我也遇到了同样的问题,无法找到完美的解决方案。这里是一些文章/帖子的链接,对我帮助很大-
如何在树视图中展开项目?-第三部分:
以编程方式选择树视图中的项目:
TreeView、TreeView和IsSelected:
对于那些仍在寻找解决此问题的正确方法的人,下面是一个例子。我在Dawander撰写的代码项目文章“WPF TreeView Selection”的评论中找到了这篇文章。 这是由Kenrae于2008年11月25日发布的。这对我很有效。谢谢你,肯瑞 以下是他的帖子: 与其遍历树,不如让您自己的数据对象具有IsSelected属性(我也建议使用IsExpanded属性)。使用TreeView上的ItemContainerStyle属性为树的TreeView项定义样式,该属性将这些属性从TreeView项绑定到数据对象。大概是这样的:
<Style x:Key="LibraryTreeViewItemStyle"
TargetType="{x:Type TreeViewItem}">
<Setter Property="IsExpanded"
Value="{Binding IsExpanded, Mode=TwoWay}" />
<Setter Property="IsSelected"
Value="{Binding IsSelected, Mode=TwoWay}" />
<Setter Property="FontWeight"
Value="Normal" />
<Style.Triggers>
<Trigger Property="IsSelected"
Value="True">
<Setter Property="FontWeight"
Value="Bold" />
</Trigger>
</Style.Triggers>
</Style>
<TreeView ItemsSource="{Binding Path=YourCollection}"
ItemContainerStyle="{StaticResource LibraryTreeViewItemStyle}"
ItemTemplate={StaticResource YourHierarchicalDataTemplate}/>
if (_items.Count > 0)
_treeView.SelectItem(_items[0]);
试试这个
/// <summary>
/// Selects the tree view item.
/// </summary>
/// <param name="Collection">The collection.</param>
/// <param name="Value">The value.</param>
/// <returns></returns>
private TreeViewItem SelectTreeViewItem(ItemCollection Collection, String Value)
{
if (Collection == null) return null;
foreach(TreeViewItem Item in Collection)
{
/// Find in current
if (Item.Header.Equals(Value))
{
Item.IsSelected = true;
return Item;
}
/// Find in Childs
if (Item.Items != null)
{
TreeViewItem childItem = this.SelectTreeViewItem(Item.Items, Value);
if (childItem != null)
{
Item.IsExpanded = true;
return childItem;
}
}
}
return null;
}
//
///选择树视图项。
///
///收藏。
///价值。
///
private TreeViewItem SelectTreeViewItem(ItemCollection集合,字符串值)
{
if(Collection==null)返回null;
foreach(集合中的TreeViewItem项)
{
///在当前找到
if(项目标题等于(值))
{
Item.IsSelected=true;
退货项目;
}
///在孩子身上找到
如果(Item.Items!=null)
{
TreeViewItem childItem=此项。选择TreeViewItem(Item.Items,值);
if(childItem!=null)
{
Item.IsExpanded=true;
返回子项;
}
}
}
返回null;
}
参考资料:我想我会加入我的解决方案,以防这对任何人都有帮助。请注意,按照kuninl的回答,最好的方法是使用绑定属性,如“IsSelected”,但在我的例子中,它是一个不遵循MVVM的遗留应用程序,因此我最终得出以下结论
private void ChangeSessionSelection()
{
foreach (SessionContainer item in this.treeActiveSessions.Items)
{
var treeviewItem = this.treeActiveSessions.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItem;
if (item.Session == this.selectedSession.Session)
{
treeviewItem.IsSelected = true;
treeviewItem.IsExpanded = true;
}
else
{
treeviewItem.IsSelected = false;
treeviewItem.IsExpanded = false;
}
}
}
这样做的目的是在UI中选择并展开treeview项,该项表示代码隐藏中选定的dataitem。这样做的目的是当用户在同一窗口中的items控件中的选择发生更改时,使treeview中的选择发生更改。如果要选择包含child的子项的项目,可以使用递归进行选择
public bool Select(TreeViewItem item, object select) // recursive function to set item selection in treeview
{
if (item == null)
return false;
TreeViewItem child = item.ItemContainerGenerator.ContainerFromItem(select) as TreeViewItem;
if (child != null)
{
child.IsSelected = true;
return true;
}
foreach (object c in item.Items)
{
bool result = Select(item.ItemContainerGenerator.ContainerFromItem(c) as TreeViewItem, select);
if (result == true)
return true;
}
return false;
}
我已经创建了一个方法
VisualTreeText.GetDescents
,该方法返回与指定类型匹配的元素的可枚举集合:
public static class VisualTreeExt
{
public static IEnumerable<T> GetDescendants<T>(DependencyObject parent) where T : DependencyObject
{
var count = VisualTreeHelper.GetChildrenCount(parent);
for (var i = 0; i < count; ++i)
{
// Obtain the child
var child = VisualTreeHelper.GetChild(parent, i);
if (child is T)
yield return (T)child;
// Return all the descendant children
foreach (var subItem in GetDescendants<T>(child))
yield return subItem;
}
}
}
这是一个有点脏的解决方案(可能不是最有效的),如果您使用虚拟化的TreeView,它将不起作用,因为它取决于实际视觉元素的存在。但它适用于我的情况…我成功地使用了以下代码:
public static TreeViewItem FindTviFromObjectRecursive(ItemsControl ic, object o) {
//Search for the object model in first level children (recursively)
TreeViewItem tvi = ic.ItemContainerGenerator.ContainerFromItem(o) as TreeViewItem;
if (tvi != null) return tvi;
//Loop through user object models
foreach (object i in ic.Items) {
//Get the TreeViewItem associated with the iterated object model
TreeViewItem tvi2 = ic.ItemContainerGenerator.ContainerFromItem(i) as TreeViewItem;
tvi = FindTviFromObjectRecursive(tvi2, o);
if (tvi != null) return tvi;
}
return null;
}
用法:
var tvi = FindTviFromObjectRecursive(TheTreeView, TheModel);
if (tvi != null) tvi.IsSelected = true;
private void ClearSelectedItem()
{
if (AssetTreeView.SelectedItem != null)
{
DeselectTreeViewItem(AssetTreeView.Items.Cast<TreeViewItem>());
}
}
嗯。。我知道这个问题已经问了很多年了,但是。。这个问题仍然没有快速的解决办法。。因此: 下面将执行OP要求的操作 基本上,我所做的是阅读本页中的所有答案,并按照所有相关链接创建一个一劳永逸的解决这个恼人问题的方法 好处:
- 它还支持虚拟化TreeView
- 它使用行为技术,因此XAML非常简单
- 添加依赖性属性以允许绑定到选定的TreeView项
公共静态类TreeViewSelectedItemExBehavior
{
私有静态列表isRegisteredToSelectionChanged=新列表();
公共静态只读从属属性SelectedExproperty=
DependencyProperty.RegisterAttached(“SelectedItemEx”,
类型(对象),
类型(TreeViewSelectedItemExBehavior),
新建FrameworkPropertyMetadata(新建对象(),FrameworkPropertyMetadata选项.bindstwoway默认,onSelectedItemExchange,null));
#区域选择编辑
公共静态对象GetSelectedItemEx(TreeView目标)
{
返回target.GetValue(SelectedItemExProperty);
}
公共静态void SetSelectedItemEx(TreeView目标,对象值)
{
target.SetValue(SelectedItemExProperty,value);
var treeViewItemToSelect=GetTreeViewItem(目标,值);
if(treeViewItemToSelect==null)
{
如果(target.SelectedItem==null)
返回;
var treeViewItemToUnSelect=GetTreeViewItem(target,target.SelectedItem);
treeViewItemToUnSelect.isselect=false;
}
其他的
treeViewItemToSelect.IsSelected=true;
}
SelectedItemExchange上的公共静态无效(DependencyObject depObj、DependencyPropertyChangedEventArgs e)
{
var treeView=depObj作为treeView;
if(treeView==null)
返回;
如果(
if (_items.Count > 0)
_treeView.SelectItem(_items[0]);
if (TreeView1.Items.Count > 0)
(TreeView1.Items[0] as TreeViewItem).IsSelected = true;
private void MouseDownEventProcessing(TreeNodeMouseClickEventArgs e)
{
tvEmployeeDirectory.SelectedNode = e.Node;
}
private static void DeselectTreeViewItem(IEnumerable<TreeViewItem> treeViewItems)
{
foreach (var treeViewItem in treeViewItems)
{
if (treeViewItem.IsSelected)
{
treeViewItem.IsSelected = false;
return;
}
DeselectTreeViewItem(treeViewItem.Items.Cast<TreeViewItem>());
}
}
private void ClearSelectedItem()
{
if (AssetTreeView.SelectedItem != null)
{
DeselectTreeViewItem(AssetTreeView.Items.Cast<TreeViewItem>());
}
}
TreeViewItem FindTreeViewItem( Stack<object> nodeStack, TreeView treeView )
{
ItemsControl itemsControl = treeView;
while (nodeStack.Count > 0) {
object node = nodeStack.Pop();
bool found = false;
foreach (object item in itemsControl.Items) {
if (item == node) {
found = true;
if (itemsControl.ItemContainerGenerator.ContainerFromItem( item ) is TreeViewItem treeViewItem) {
if (nodeStack.Count == 0) {
return treeViewItem;
}
itemsControl = treeViewItem;
treeViewItem.IsExpanded = true;
treeViewItem.UpdateLayout();
break;
}
}
}
if (!found) {
return null;
}
}
return null;
}
// Build nodeStack here from your data
TreeViewItem treeViewItem = FindTreeViewItem( nodeStack, treeView );
if (treeViewItem != null) {
treeViewItem.IsSelected = true;
treeViewItem.BringIntoView();
}
public class TreeViewHelper<TModel>
{
public TreeViewHelper(TreeView treeView, Func<TModel, TModel> getParent, Func<TModel, IList<TModel>> getSubItems)
{
TreeView = treeView;
GetParent = getParent;
GetSubItems = getSubItems;
}
public TreeView TreeView { get; }
public Func<TModel, TModel> GetParent { get; }
public Func<TModel, IList<TModel>> GetSubItems { get; }
public void SelectItemWhileLoaded(TModel node, IList<TModel> rootNodes)
{
if (TreeView.IsLoaded)
{
SelectItem(node, rootNodes);
}
else
{
TreeView.Loaded += TreeView_Loaded;
void TreeView_Loaded(object sender, System.Windows.RoutedEventArgs e)
{
TreeView.Loaded -= TreeView_Loaded;
SelectItem(node, rootNodes);
}
}
}
public void SelectItem(TModel node, IList<TModel> rootNodes)
{
Stack<TModel> nodes = new Stack<TModel>();
//push into stack
while (!rootNodes.Contains(node))
{
nodes.Push(node);
node = GetParent(node);
}
TreeViewItem treeViewItem = TreeView.ItemContainerGenerator
.ContainerFromItem(node) as TreeViewItem;
if (nodes.Count == 0)
{
//Top level
treeViewItem.IsSelected = true;
treeViewItem.BringIntoView();
return;
}
Expanded(true);
void Expanded(bool top)
{
if (!top)
{
treeViewItem = treeViewItem.ItemContainerGenerator
.ContainerFromItem(node) as TreeViewItem;
if (nodes.Count == 0)
{
treeViewItem.IsSelected = true;
treeViewItem.BringIntoView();
return;
}
}
node = nodes.Pop();
treeViewItem.IsExpanded = true;
if (treeViewItem.ItemContainerGenerator.Status == GeneratorStatus.ContainersGenerated)
{
Expanded(true);
}
else
{
//Lazy
treeViewItem.ItemContainerGenerator.StatusChanged += ItemContainerGenerator_StatusChanged;
}
}
void ItemContainerGenerator_StatusChanged(object sender, EventArgs e)
{
if (treeViewItem.ItemContainerGenerator.Status == GeneratorStatus.ContainersGenerated)
{
treeViewItem.ItemContainerGenerator.StatusChanged -= ItemContainerGenerator_StatusChanged;
Expanded(false);
}
}
}
}