如何使用wpf中的复选框开发树视图？

Question

我有一个要求,我需要TreeView动态添加节点,并使用CheckBoxes 添加节点.如果CheckBox选择了一个孩子也被选中.

主要是我想TreeView动态添加数据.

Answer 1

一旦你知道如何,这非常简单.

CheckableItem为树视图项数据创建一个视图模型类(我在这里调用它).它需要这三件事:

• 它必须实现INotifyPropertyChanged.
• 它需要一个Children类型的属性ObservableCollection<CheckableItem>.
• 它需要一个IsChecked类型的属性Visibility,在其setter中,它会引发PropertyChanged并遍历项目Children并设置它们的IsChecked属性.

在此类中实现其他属性以将项目的数据公开给绑定(我的示例只是假定调用了某些内容Value).或者你可以实现一个Item类的类object并ContentPresenter在模板中使用a ,但我会留意你.

现在HierarchicalDataTemplate为您的类创建一个如下所示的类:

<HierarchicalDataTemplate
    DataType="{x:Type local:CheckableItem}" 
    ItemsSource="{Binding Children}">
    <StackPanel Orientation="Horizontal">
        <CheckBox IsChecked="{Binding IsChecked}"/>
        <TextBlock Text="{Binding Value}"/>
    </StackPanel>
</HierarchicalDataTemplate>

...并TreeView使用它(我假设你已经填充了这些对象的集合,当然):

<TreeView ItemsSource="{Binding MyCollectionOfCheckableItems}"/>

工作原理:TreeView使用它HierarchicalDataTemplate来渲染其中的每个项目ItemsSource.这HierarchicalDataTemplate是一个模板,它创建一个HeaderedItemsControl(在这种情况下为a TreeViewItem),使用它的模板来呈现标题,然后使用它ItemsSource作为控件项的源 - 由于它们都是CheckableItems,因此被转换为TreeViewItems HierarchicalDataTemplate.在那之后,它一直是乌龟.

这是一个非常好的概述TreeView实际上如何实际工作,虽然我发现的大多数例子,它有很多花里胡哨,很难看出基本原则是多么简单.如果你了解MVVM,那么前一段是你需要知道的90%.

Answer 2

看一下这个:

DataModel.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace WpfApplication102
{
    public class Family : DependencyObject
    {
        public string Name { get; set; }
        public List<Person> Members { get; set; }
    }

    public class Person : DependencyObject
    {
        public string Name { get; set; }
    }
}

ItemHelper.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace WpfApplication102
{
    public class ItemHelper : DependencyObject
    {
        public static readonly DependencyProperty IsCheckedProperty = DependencyProperty.RegisterAttached("IsChecked", typeof(bool?), typeof(ItemHelper), new PropertyMetadata(false, new PropertyChangedCallback(OnIsCheckedPropertyChanged)));
        private static void OnIsCheckedPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (d is Family && ((bool?)e.NewValue).HasValue)
                foreach (Person p in (d as Family).Members)
                    ItemHelper.SetIsChecked(p, (bool?)e.NewValue);

            if (d is Person)
            {
                int checked = ((d as Person).GetValue(ItemHelper.ParentProperty) as Family).Members.Where(x => ItemHelper.GetIsChecked(x) == true).Count();
                int unchecked = ((d as Person).GetValue(ItemHelper.ParentProperty) as Family).Members.Where(x => ItemHelper.GetIsChecked(x) == false).Count();
                if (unchecked > 0 && checked > 0)
                {
                    ItemHelper.SetIsChecked((d as Person).GetValue(ItemHelper.ParentProperty) as DependencyObject, null);
                    return;
                }
                if (checked > 0)
                {
                    ItemHelper.SetIsChecked((d as Person).GetValue(ItemHelper.ParentProperty) as DependencyObject, true);
                    return;
                }
                ItemHelper.SetIsChecked((d as Person).GetValue(ItemHelper.ParentProperty) as DependencyObject, false);
            }
        }
        public static void SetIsChecked(DependencyObject element, bool? IsChecked)
        {
            element.SetValue(ItemHelper.IsCheckedProperty, IsChecked);
        }
        public static bool? GetIsChecked(DependencyObject element)
        {
            return (bool?)element.GetValue(ItemHelper.IsCheckedProperty);
        }

        public static readonly DependencyProperty ParentProperty = DependencyProperty.RegisterAttached("Parent", typeof(object), typeof(ItemHelper));
        public static void SetParent(DependencyObject element, object Parent)
        {
            element.SetValue(ItemHelper.ParentProperty, Parent);
        }
        public static object GetParent(DependencyObject element)
        {
            return (object)element.GetValue(ItemHelper.ParentProperty);
        }
    }
}

MainWindow.xaml

<Window x:Class="WpfApplication102.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApplication102"
        Title="MainWindow" Height="220" Width="250">

    <StackPanel>

        <TreeView x:Name="treeView" ItemsSource="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=Families}">
            <TreeView.Resources>
                <HierarchicalDataTemplate DataType="{x:Type local:Family}" ItemsSource="{Binding Members}" >
                    <CheckBox Content="{Binding Name}" IsChecked="{Binding Path=(local:ItemHelper.IsChecked), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" >
                        <CheckBox.Style>
                            <Style TargetType="{x:Type CheckBox}">
                                <Setter Property="Foreground" Value="Black"/>
                                <Setter Property="Visibility" Value="Visible"/>
                                <Style.Triggers>
                                    <DataTrigger Binding="{Binding Path=(local:ItemHelper.IsChecked)}" Value="False" >
                                        <Setter Property="Foreground" Value="LightGray"/>
                                    </DataTrigger>
                                </Style.Triggers>
                            </Style>
                        </CheckBox.Style>
                    </CheckBox>
                </HierarchicalDataTemplate>
                <DataTemplate DataType="{x:Type local:Person}" >
                    <CheckBox Content="{Binding Name}" IsChecked="{Binding Path=(local:ItemHelper.IsChecked), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" >
                        <CheckBox.Style>
                            <Style TargetType="{x:Type CheckBox}">
                                <Setter Property="Foreground" Value="Black"/>
                                <Setter Property="Visibility" Value="Visible"/>
                                <Style.Triggers>
                                    <DataTrigger Binding="{Binding Path=(local:ItemHelper.IsChecked)}" Value="False" >
                                        <Setter Property="Foreground" Value="LightGray"/>
                                    </DataTrigger>
                                </Style.Triggers>
                            </Style>
                        </CheckBox.Style>
                    </CheckBox>
                </DataTemplate>
            </TreeView.Resources>
            <TreeView.ItemContainerStyle>
                <Style TargetType="{x:Type TreeViewItem}">
                    <Setter Property="IsExpanded" Value="True"/>
                </Style>
            </TreeView.ItemContainerStyle>
        </TreeView>

        <Button Content="?" Click="Button_PrintCrew_Click" />

        <TextBlock x:Name="textBoxCrew"/>

    </StackPanel>

</Window>

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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 WpfApplication102
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public ObservableCollection<Family> Families { get; set; }

        public MainWindow()
        {
            InitializeComponent();

            this.Families = new ObservableCollection<Family>();
            this.Families.Add(new Family() { Name = "Simpsons", Members = new List<Person>() { new Person() { Name = "Homer" }, new Person() { Name = "Bart" } } });
            this.Families.Add(new Family() { Name = "Griffin", Members = new List<Person>() { new Person() { Name = "Peter" }, new Person() { Name = "Stewie" } } });
            this.Families.Add(new Family() { Name = "Fry", Members = new List<Person>() { new Person() { Name = "Philip J." } } });

            foreach (Family family in this.Families)
                foreach (Person person in family.Members)
                    person.SetValue(ItemHelper.ParentProperty, family);
        }

        private void Button_PrintCrew_Click(object sender, RoutedEventArgs e)
        {
            string crew = "";
            foreach (Family family in this.Families)
                foreach (Person person in family.Members)
                    if (ItemHelper.GetIsChecked(person) == true)
                        crew += person.Name + ", ";
            crew = crew.TrimEnd(new char[] { ',', ' ' });
            this.textBoxCrew.Text = "Your crew: " + crew;
        }
    }
}