如何正确绑定WPF TreeView控件并有效显示数据层次结构？

Question

好的，所以我通常会等到最后一刻提交问题，但我真的可以使用一些帮助。

我正在尝试将ObservableCollection<Contact_Info>绑定到WPF TreeView控件。 Contact_Info包含联系信息的属性，并实现INotifyPropertyChanged 。 它还包含给定Contact的更详细信息的列表。

我遇到两件事情有困难。 1）我需要在TreeViewItem标题上显示公司的名称，但是，很多联系人都缺少公司名称，我想使用名字和姓氏。 我试图使用像FallBackValue和TargetNullValue这样的东西，但是CompanyName不是null，它只是空的所以我似乎无法做到这一点。 我需要转换器吗？ 2）我似乎无法使层次结构正确，我希望同一AccountID的所有联系人在TreeViewItem组合在一起。 目前，我只能在TreeViewItem上显示公司名称并展开它显示一个空白值，并且仍然显示重复的公司名称。

我在DockPanel.Resources下放置HierarchicalDataTemplate的代码（不确定这是不是正确的地方）。

    <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面尝试过的最新代码。 我觉得我非常接近但是在这一点上我真的可以使用SO的帮助。

其他课程有点长，如果您需要更多，请告诉我。 非常感谢您提供的任何帮助！

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，但不会将公司组合在一起......

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 。 使用你的代码（减少到最小需要），但使用ObservableCollection驱动集合，它对我来说很好。

请注意，我的代码可以正常使用List，因为它全部是静态的，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：我正在使用代码来回答这个问题，以保持简单，但我不建议在任何真正的应用程序中使用任何此类

MainWindow.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> 

MainWindow.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; } } } 

截图

Answer 2

根据我的理解，您的OppDataList是给定合同信息的子属性，您希望它是可折叠的。

在这种情况下你可以做到

    <ListBox ItemsSource="{Binding YourContactList}">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <Expander Header="{Binding ProjectName}">
                    <Expander Header="{Binding CompanyName}">
                        <ListBox ItemsSource="{Binding OppDataList}">
                            <!--Your OppDataList display-->
                        </ListBox>
                    </Expander>
                </Expander>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

最终结果看起来与此类似

+Contract1
-Contract2
   -Project2
      -Company2
         -Opp
            1
            2
            3
+Contract3