TreeView控件自动选择父用户选择过了一会儿 [英] TreeView auto-selecting parent after user selects child
问题描述
在我的窗口，我有一个TreeView和TextBox。假装文本框用于编写自定义脚本和TreeView的是一种方法，选择一个功能接入;认为水晶报表的脚本编辑器。
In my window I have a TreeView and TextBox. Pretend the TextBox is used for writing a custom script and the TreeView is a way to select a function to insert; think Crystal Report script editor.
我的目标是让用户单击TreeView中的孩子之一，且该子女插入到文本框。孩子是一个函数签名，并驻留在父节点下。然后，用户可以导航到该文本框，选择功能参数之一，另一个函数签名代替它。要做到这一点，我处理TreeView的SelectedItemChanged事件，设置文本框的SelectedText，然后尽量突出它改变后的文字。
My goal is for a user to click one of the children of the TreeView and that child inserts into the TextBox. The child is a function signature and resides under a Parent node. The user can then navigate to the TextBox, select one of the function parameters and replace it with another function signature. To accomplish this, I handle the TreeView's SelectedItemChanged event, set the TextBox's SelectedText, and then try to highlight the text after it's changed.
TextBox的SelectedText正确正在交换。但是，文本没有被突出显示，并滚动条滚动不向选定的文本。
The SelectedText of the TextBox is properly being swapped. However, the text is not being highlighted and the scrollbar isn't scrolling to the selected text.
下面是测试项目，我写重现我的XAML行为：
<Window x:Class="SelectedTextWeirdness.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:System="clr-namespace:System;assembly=mscorlib"
xmlns:SelectedTextWeirdness="clr-namespace:SelectedTextWeirdness" Title="MainWindow" Width="600" Height="600"
x:Name="Me">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<TreeView Grid.Row="0" x:Name="treeView" ItemsSource="{Binding ElementName=Me, Path=TreeViewItems, Mode=TwoWay}"
SelectedItemChanged="treeView_SelectedItemChanged" Margin="10">
<TreeView.Resources>
<HierarchicalDataTemplate DataType="{x:Type SelectedTextWeirdness:Parent}" ItemsSource="{Binding Children}">
<TextBlock Text="{Binding Name}" />
</HierarchicalDataTemplate>
<DataTemplate DataType="{x:Type SelectedTextWeirdness:Child}">
<TextBlock Text="{Binding Name}" />
</DataTemplate>
</TreeView.Resources>
</TreeView>
<TextBox Grid.Row="1" x:Name="scriptTextBox" Margin="10" Height="200" Width="Auto" FontFamily="Consolas, Courier New"
HorizontalScrollBarVisibility="Visible" VerticalScrollBarVisibility="Auto"
MaxLines="9999" AcceptsReturn="True" AcceptsTab="True" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
Text="{Binding Path=Script, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
/>
</Grid>
</Window>
这里是后台代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace SelectedTextWeirdness
{
public class Child
{
public string Name
{
get;
set;
}
}
public class Parent
{
public string Name
{
get;
set;
}
public List<Child> Children
{
get;
set;
}
}
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public List<Parent> TreeViewItems
{
get;
set;
}
public MainWindow()
{
BuildTreeViewItems();
InitializeComponent();
}
private void BuildTreeViewItems()
{
TreeViewItems = new List<Parent>()
{
new Parent()
{
Name = "Parent1",
Children =
new List<Child>()
{
new Child() {Name = "ReallyLongFunctionNameNumber1(ReallyLongLeft1, ReallyLongRight1)"},
new Child() {Name = "ReallyLongFunctionNameNumber2(ReallyLongLeft2, ReallyLongRight2)"},
new Child() {Name = "ReallyLongFunctionNameNumber3(ReallyLongLeft3, ReallyLongRight3)"},
new Child() {Name = "ReallyLongFunctionNameNumber4(ReallyLongLeft4, ReallyLongRight4)"},
new Child() {Name = "ReallyLongFunctionNameNumber5(ReallyLongLeft5, ReallyLongRight5)"}
}
},
new Parent()
{
Name = "Parent2",
Children =
new List<Child>()
{
new Child() {Name = "ReallyLongFunctionNameNumber1(ReallyLongLeft1, ReallyLongRight1)"},
new Child() {Name = "ReallyLongFunctionNameNumber2(ReallyLongLeft2, ReallyLongRight2)"},
new Child() {Name = "ReallyLongFunctionNameNumber3(ReallyLongLeft3, ReallyLongRight3)"},
new Child() {Name = "ReallyLongFunctionNameNumber4(ReallyLongLeft4, ReallyLongRight4)"},
new Child() {Name = "ReallyLongFunctionNameNumber5(ReallyLongLeft5, ReallyLongRight5)"}
}
}
};
}
private void treeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
var tree = (TreeView)sender;
var selectedItem = tree.SelectedItem as Child;
if (selectedItem != null)
{
int selectionStart = scriptTextBox.SelectionStart;
string selectedText = selectedItem.Name;
scriptTextBox.SelectedText = selectedText;
scriptTextBox.Focus();
scriptTextBox.Select(selectionStart, selectedText.Length);
}
}
}
}
我已经尝试设置SelectedItemChanged e.Handled = TRUE。没有工作。我试过处理TextBox的引发LostFocus和设置e.Handled =真实的，没有奏效。这似乎只当我使用HierarchicalDateTemplate发生。如果我改变的数据只有一个级别，这种设置工作正常。
I have tried setting the SelectedItemChanged e.Handled = true. That didn't work. I've tried handling the LostFocus of the TextBox and setting e.Handled = true and that hasn't worked. This only seems to happen when I use the HierarchicalDateTemplate. If I change the data to be one level only, this setup works fine.
任何想法？
推荐答案
THX一个良好的书面问题。
中的核心问题是有一个事件处理程序中的一个焦点（）的变化。由BeginInvoke的内调用它推迟福克斯结果
是这样的：
Thx for a well-written question.
The core issue is to have a Focus() change within an event handler. Postpone the Focus by calling it within a BeginInvoke.
Something like :
delegate void voidDelegate();
private void treeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
var tree = (TreeView)sender;
var selectedItem = tree.SelectedItem as Child;
if (selectedItem != null)
{
int selectionStart = scriptTextBox.SelectionStart;
string selectedText = selectedItem.Name;
voidDelegate giveFocusDelegate = new voidDelegate(giveFocus);
Dispatcher.BeginInvoke(giveFocusDelegate, new object[] { });
scriptTextBox.SelectedText = selectedText;
}
}
private void giveFocus()
{ scriptTextBox.Focus();
}
应该让你从你的目标越来越近。
Should get you closer from your goal.
编辑：我们怎么知道这将工作
Edit : How do we know this will work ?
该操作被添加到分派的事件队列在
中规定的DispatcherPriority
The operation is added to the event queue of the Dispatcher at the specified DispatcherPriority.
所以，无论该任务的优先级在那里你调用BeginInvoke，当调用可能发生的是之后当前操作的执行终止最近的时间为：beginInvoked操作的调度，它在单个线程的工作队列推的地方。
So whatever the priority of the task where you call beginInvoke, the nearest time when the call can happen is right after the execution of current operation ended : the beginInvoked operation is 'pushed' somewhere on the queue of the dispatcher, which works on a single thread.
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