c# - 如何正确绑定(bind) WPF TreeView 控件并有效地显示数据的层次结构？

Question

好的，所以我通常会等到最后一刻才提交问题，但我真的需要一些帮助。

我正在尝试绑定(bind) ObservableCollection<Contact_Info>到 WPF TreeView控制。 Contact_Info 包含联系信息的属性并实现 INotifyPropertyChanged .它还包含给定 Contact 的更详细信息列表。 .

我在两件事上遇到了麻烦。 1) 我需要在 TreeViewItem 上显示header 公司名称 但是，很多联系人都缺少公司名称，我想在其中使用名字和姓氏。我曾尝试使用类似 FallBackValue 的东西和 TargetNullValue但 CompanyName 不为空，它只是空的，所以我似乎无法正确理解。我需要转换器吗？ 2)我似乎无法获得正确的层次结构，我希望同一 AccountID 的所有联系人在 TreeViewItem 中分组在一起.目前，我只能让公司名称显示在 TreeViewItem 上并展开它显示一个空白值，并且仍然显示重复的公司名称。

我尝试将 HierarchicalDataTemplate 放在 DockPanel.Resources 下的代码(也不确定那是否是正确的位置)。

    <local:Main_Interface x:Key="MyList" />
       <HierarchicalDataTemplate DataType = "{x:Type 
                                 local:Contact_Info}" ItemsSource = "{Binding Path=OppDataList}">
            <TextBlock Text="{Binding Path=CompanyName}"/>
        </HierarchicalDataTemplate>
       <DataTemplate DataType = "{x:Type sharpspring:SharpspringOpportunityDataModel}" >
             <TextBlock Text="{Binding Path=ProjectName}"/>
        </DataTemplate>

上面的代码是我在无数其他方法中尝试过的最新方法。我觉得我真的很接近，但在这一点上我真的可以使用 SO 的一些帮助..

其他类(class)有点长，如果您需要更多，请告诉我。非常感谢提供的任何帮助!

编辑 1:Contact_Info

public class Contact_Info : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    internal SharpspringLeadDataModel LeadDataModel;
    internal SharpspringOpportunityDataModel OppData;
    public List<SharpspringOpportunityDataModel> OppDataList { get; set; }// Should i make this ObservableCollection?

    public Project_Info ProjectInfo { get; set; }
    public bool IsDirty { get; set; }
    public bool IsNew { get; set; }

    #region Properties

    public long AccountID
    {
        get => LeadDataModel.AccountID;
        set
        {
            if (value != LeadDataModel.AccountID)
            {
                LeadDataModel.AccountID = value;
                NotifyPropertyChanged();
            }
        }
    }
    public long LeadID
    {
        get => LeadDataModel.LeadID;
        set
        {
            if (value != LeadDataModel.LeadID)
            {
                LeadDataModel.LeadID = value;
                NotifyPropertyChanged();
            }
        }
    }
    // Lead Info
    public string CompanyName
    {
        get => LeadDataModel.CompanyName;
        set
        {
            if (value != LeadDataModel.CompanyName)
            {
                LeadDataModel.FaxNumber = value;
                NotifyPropertyChanged();
            }
        }
    }

    public Contact_Info(SharpspringLeadDataModel lead, SharpspringOpportunityDataModel opp)
    {
        LeadDataModel = lead;
        OppData = opp;
        ProjectInfo = new Project_Info(this);

    }

    public SharpspringLeadDataModel GetDataModel()
    {
        return LeadDataModel;
    }

    public SharpspringOpportunityDataModel GetOppModel()
    {
        return OppData;
    }

    public Project_Info GetProjectInfoModel()
    {
        return ProjectInfo;
    }

    public void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
    {
        IsDirty = true;
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

编辑 2:当前填充树但不将公司组合在一起...

private void PopulateTreeView(List<SharpspringLeadDataModel> lead_list, List<SharpspringOpportunityDataModel> opp_list)
    {
        Contacts = new ObservableCollection<Contact_Info>();
        var complete2 =
                        from lead in lead_list
                        let oppList = from o in opp_list
                                      where o.PrimaryLeadID == lead.LeadID
                                      select o
                        select new Contact_Info()
                        {
                            LeadDataModel = lead,
                            OppData = oppList.DefaultIfEmpty(new SharpspringOpportunityDataModel()).First(),
                            OppDataList = oppList.ToList(),
                        };

        Contacts = complete2.ToObservableCollection();
   Lead_Treeview.ItemsSource = Contacts;
}

Answer 1

我认为您的问题实际上是使用 List 而不是 OppDataList 的 ObservableCollection。使用您的代码(减少到最少需要)但使用 ObservableCollection 驱动集合，它对我来说很好。

请注意，我的代码可以与 List 一起正常工作，即使因为它都是静态的，但在适当的应用程序中，您需要 OC 来跟踪集合中的更改。

免责声明:我使用隐藏代码来回答这个问题以保持简单，但我不建议在任何真实应用中使用此类代码

主窗口.xaml

<Window x:Class="WpfApp1.MainWindow"
        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:local="clr-namespace:WpfApp1"
        mc:Ignorable="d"
        Title="MainWindow" Height="240" Width="320">
    <TreeView ItemsSource="{Binding Contacts}">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate DataType="{x:Type local:Contact_Info}" ItemsSource="{Binding Path=OppDataList}">
                <HierarchicalDataTemplate.ItemTemplate>
                    <DataTemplate DataType="{x:Type local:SharpspringOpportunityDataModel}">
                        <TextBlock Text="{Binding Path=ProjectName}" />
                    </DataTemplate>
                </HierarchicalDataTemplate.ItemTemplate>
                <TextBlock Text="{Binding Path=CompanyName}" />
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>
</Window>

主窗口.xaml.cs

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using WpfApp1.Annotations;

namespace WpfApp1
{
    public partial class MainWindow : INotifyPropertyChanged
    {
        public MainWindow()
        {
            InitializeComponent();
            DataContext = this;
        }

        public ObservableCollection<Contact_Info> Contacts { get; } =
            new ObservableCollection<Contact_Info>
            {
                new Contact_Info
                {
                    CompanyName = "Apple",
                    OppDataList = {new SharpspringOpportunityDataModel {ProjectName = "World take over"}}
                },
                new Contact_Info
                {
                    CompanyName = "Google",
                    OppDataList = {new SharpspringOpportunityDataModel {ProjectName = "World take over"}}
                },
                new Contact_Info
                {
                    CompanyName = "Microsoft",
                    OppDataList = {new SharpspringOpportunityDataModel {ProjectName = "World take over"}}
                }
            };


        public event PropertyChangedEventHandler PropertyChanged;

        [NotifyPropertyChangedInvocator]
        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public class Contact_Info
    {
        public string CompanyName { get; set; }

        public ObservableCollection<SharpspringOpportunityDataModel> OppDataList { get; } =
            new ObservableCollection<SharpspringOpportunityDataModel>();
    }

    public class SharpspringOpportunityDataModel
    {
        public string ProjectName { get; set; }
    }
}

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