TreeView 内容未显示在用户控件上

问题描述

我正在 WPF 中开发我的第一个用户控件。我的目标是拥有一个基于 TreeView 的控件，每个条目带有一个复选框 + 图像 + 标签。在我的应用程序中，这种 TreeView 会出现多次。除了一件事，我已经做了很多工作：我最初添加的数据没有显示在用户控件中。

这是我所拥有的：托管窗口 XAML：

<Window x:Class="Calm.View.Projectmanagementwindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:uc="clr-namespace:Calm.View"
        mc:Ignorable="d"
        Title="Projectmanagement" Height="450" Width="800">
    <Grid>
        <Grid.ColumnDeFinitions>
            <ColumnDeFinition Width="5" />
            <ColumnDeFinition Width="45*" />
            <ColumnDeFinition Width="5" />
            <ColumnDeFinition Width="60*" />
            <ColumnDeFinition Width="5" />
        </Grid.ColumnDeFinitions>
        <Grid.RowDeFinitions>
            <RowDeFinition Height="5"/>
            <RowDeFinition Height="*"/>
            <RowDeFinition Height="5"/>
        </Grid.RowDeFinitions>
        
        <!-- Linke Seite -->
        <Grid Grid.Column="1" Grid.Row="1">
            <Grid.ColumnDeFinitions>
                <ColumnDeFinition Width="50*" />
                <ColumnDeFinition Width="50*" />
            </Grid.ColumnDeFinitions>
            <Grid.RowDeFinitions>
                <RowDeFinition Height="*"/>
                <RowDeFinition Height="35"/>
                <RowDeFinition Height="125"/>
            </Grid.RowDeFinitions>

            <!-- Todo: Binding not wirking properly -->
            <uc:CheckableTreeView Grid.Column="0" Grid.ColumnSpan="2" Grid.Row="0" x:Name="PMTree"
                                     CheckableItemsSource="{Binding Path=ProjektManagementItems.TreeItems}"/>

            <!-- Todo: Rplace Buttons with the Functionality -->
            <StackPanel Grid.Column="0" Grid.ColumnSpan="2" Grid.Row="1" Orientation="Horizontal">
                <Button Width="150" Margin="3" Click="Button_Click">InsertUserControlContent</Button>
                <Button Width="150" Margin="3" Click="Button_Click2">GetCheckedIetms</Button>
                
            </StackPanel>

            <!-- Todo: Remove TreeView after usercontrol works -->
            <TreeView x:Name="ThisTree" ItemsSource="{Binding Path=ProjektManagementItems.TreeItems}"
                      Grid.Column="0" Grid.ColumnSpan="2" Grid.Row="2">
                <TreeView.ItemTemplate>
                    <HierarchicalDataTemplate ItemsSource="{Binding ChildItems}">
                        <StackPanel Orientation="Horizontal">
                            <CheckBox VerticalAlignment="Center" IsChecked="{Binding IsChecked}"/>
                            <Image Width="20" Margin="3" Source="{Binding Image}"/>
                            <TextBlock VerticalAlignment="Center" Text="{Binding Name}"/>
                        </StackPanel>
                    </HierarchicalDataTemplate>
                </TreeView.ItemTemplate>
            </TreeView>
            

        </Grid>

    </Grid>
</Window>

托管窗口 XAML.cs（本质上）：

public class Projectmanagementviewmodel : PropertyChangedEventImp
    {
        private static readonly log4net.ILog _log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
        #region properties
        private CheckableTreeStructContext _projektManagementItems;

        /// <summary>
        /// This object handles the tree for a checkableTreeView
        /// </summary>
        public CheckableTreeStructContext ProjektManagementItems { get => _projektManagementItems; }
        #endregion

        #region constructor
        public Projectmanagementviewmodel()
        {
            try
            {
                _projektManagementItems = new CheckableTreeStructContext();

                // Todo: remove dummyData
                LoadTreeViewData();
            }
            catch (Exception ex)
            {
                _log.Error("Konstruktor Projectmanagementviewmodel",ex);

                throw ex;

            }
        }
        #endregion

        #region methods
        /// <summary>
        /// Use this method to load the necessary data for the tree view into the ProjektManagementItems object
        /// </summary>
        private void LoadTreeViewData()
        {
            // Todo: remove dummyData
            var tempItemR = new CheckableTreeViewElementBasis("Root1","konzept");
            var tempItem1 = new CheckableTreeViewElementBasis("Child1.1","projekt");
            var tempItem2 = new CheckableTreeViewElementBasis("Child1.1.1","gruppe");
            var tempItem3 = new CheckableTreeViewElementBasis("Child1.2","projekt");

            tempItem1.AddChildItem(tempItem2);

            tempItemR.AddChildItem(tempItem1);
            tempItemR.AddChildItem(tempItem3);

            _projektManagementItems.AddItem(tempItemR);

            tempItemR = new CheckableTreeViewElementBasis("Root2","konzept");
            tempItem1 = new CheckableTreeViewElementBasis("Child2.1","projekt");
            tempItem2 = new CheckableTreeViewElementBasis("Child2.1.1","gruppe");
            tempItem3 = new CheckableTreeViewElementBasis("Child2.2","projekt");

            tempItem1.AddChildItem(tempItem2);

            tempItemR.AddChildItem(tempItem1);
            tempItemR.AddChildItem(tempItem3);

            _projektManagementItems.AddItem(tempItemR);

            SetProperty("CheckableTreeStructContext");
        }
        #endregion
    }

CheckableTreeViewElementBasis 当然有属性 ChildItems、IsChecked、Image 和 Name。

（“ThisTree”正是我想要的）

这是我的用户控件：用户控制 XAML：

<UserControl x:Class="Calm.View.CheckableTreeView"
             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:Calm.View"
             mc:Ignorable="d" 
             Name="MyTestName"
             d:DesignHeight="450" d:DesignWidth="800">

    <!-- Todo: Binding not showing properly -->
    <TreeView x:Name="CheckableTree"
                      Grid.Column="0" Grid.ColumnSpan="2" Grid.Row="2" ItemsSource="{Binding CheckableItemsSource}">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding ChildItems}">
                <StackPanel Orientation="Horizontal">
                    <CheckBox VerticalAlignment="Center" IsChecked="{Binding IsChecked}"/>
                    <Image Width="20" Margin="3" Source="{Binding Image}"/>
                    <TextBlock VerticalAlignment="Center" Text="{Binding Name}"/>
                </StackPanel>
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>
</UserControl>

用户控制 XAML.cs：

using Calm.viewmodel;
using System;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Controls;

namespace Calm.View
{
    /// <summary>
    /// Interaktionslogik für CheckableTreeView.xaml
    /// </summary>
    public partial class CheckableTreeView : UserControl
    {
        private static readonly log4net.ILog _log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

        #region Addition control properties
        /// <summary>
        /// DependencyProperty which holds the content for the treeview
        /// </summary>
        public ObservableCollection<CheckableTreeViewElementBasis> CheckableItemsSource
        {
            get { return (ObservableCollection<CheckableTreeViewElementBasis>)GetValue(CheckableItemsSourceProperty); }
            set
            {
                SetValue(CheckableItemsSourceProperty,value);
            }
        }

        // Using a DependencyProperty as the backing store for ItemsSourceProperty.  This enables animation,styling,binding,etc...
        public static readonly DependencyProperty CheckableItemsSourceProperty =
            DependencyProperty.Register("CheckableItemsSource",typeof(ObservableCollection<CheckableTreeViewElementBasis>),typeof(CheckableTreeView),new PropertyMetadata(new ObservableCollection<CheckableTreeViewElementBasis>()));

        /// <summary>
        /// To get access the basefunctionality of the treeview use this property
        /// </summary>
        public TreeView BaseTree { get { return CheckableTree; } }
        #endregion

        #region Constructor
        public CheckableTreeView()
        {
            try
            {
                InitializeComponent();

                //viewmodel init
                DataContext = this;
            }

            catch (Exception ex)
            {
                _log.Error("Konstruktor CheckableTreeView",ex);
                MessageBox.Show(ex.Message,GenaralConstants.MessageBoxText_ApplicationError,MessageBoxButton.OK,MessageBoxImage.Error);

            }
        }
        #endregion
    }
}

现在非用户控件 treeView "ThisTree" 可以完美地打开 Projectmanagementwindow。用户控件“PMTree”不显示内容。在按钮上我有一些测试功能，这清楚地表明，如果 DataContext = this; 未使用，用户控件的内容已填充并反映“ThisTree”的选中状态但不可见。

如果我使用 DataContext = this;，CheckableItemsSource 在启动时为空。如果我这样做：

PMTree.CheckableItemsSource = ProjektManagementItems.TreeItems

之后 TreeView 剂量出现。

谁能告诉我如何让用户 treeView 在打开 Projectmanagementwindow 时显示？我不想使用“已加载”事件。

I System 相关：Visual Studio 2019、C# .Net Framework 4.8、Windows 10 64 位。

解决方法

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binding binding c#c#treeview treeview user-controls wpf-controls

TreeView 内容未显示在用户控件上

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