Question

预先感谢

我想将可观察的集合绑定到WPF中的TreeView，以便它应将每个TreeView节点显示为CountryType。 TreeView从后面的代码绑定到此集合。

这是代码：

public partial class MyUserControl: UserControl
{
    public ObservableCollection<Person> myList { get; set; }

    public IEnumerable<PersonViewModel> PersonViewModelList { get; set; }

     public MyUserControl()
     {
       InitializeComponent();
       PopulateCollection();
       DataContext = this;
     }

     private void PopulateCollection()
        {
            myList = new ObservableCollection<Person>()
            {
                new Person{ Name="Name 1", Age=21, CountryType = CountryList.India},
                new Person{ Name="Name 2", Age=21, CountryType = CountryList.US},
                new Person{ Name="Name 3", Age=24, CountryType = CountryList.Israel},
                new Person{ Name="Name 4", Age=24, CountryType = CountryList.Israel},
                new Person{ Name="Name 5", Age=24, CountryType = CountryList.Russia},
                new Person{ Name="Name 6", Age=24, CountryType = CountryList.India},
                new Person{ Name="Name 7", Age=24, CountryType = CountryList.Russia},
                new Person{ Name="Name 8", Age=24, CountryType = CountryList.Russia},
                new Person{ Name="Name 9", Age=24, CountryType = CountryList.Japan},
                new Person{ Name="Name 10", Age=24, CountryType = CountryList.Japan},
                new Person{ Name="Name 11", Age=24, CountryType = CountryList.India},
                new Person{ Name="Name 12", Age=24, CountryType = CountryList.India},
            };

            PersonViewModelList = myList.GroupBy(x => x.CountryType)
            .Select(g => new PersonViewModel()
            {
                CountryType = g.Key,
                Names = g.Select(x => x.Name).OrderBy(n => n).ToList()
            });          
        }
  }

  public class Person
    {
        public string Name { get; set; }
        public int Age { get; set; }
        public CountryList CountryType { get; set; }        
    }

    public class PersonViewModel
    {
        public CountryList CountryType { get; set; }
        public List<string> Names { get; set; }
    }

  public enum CountryList
    {
        India,
        Russia,
        US,
        Israel,
        Japan
    }

UserControl（XAML文件）

 <TreeView ItemsSource="{Binding PersonViewModelList}">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Path=Names}" DataType="{x:Type local:PersonViewModel}">
                <HierarchicalDataTemplate.ItemTemplate>
                    <DataTemplate>
                        <TextBlock Text="{Binding Path=CountryType}"></TextBlock>
                    </DataTemplate>
                </HierarchicalDataTemplate.ItemTemplate>
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>

预期：

我不太确定我应该在TreeView中进行哪些更改以使其起作用。再次感谢。

Answer 1

您当前的@Override public String toString() { return procedureName + " " + procedureDate; }类型不适合您的要求或对您的要求无效。您需要将数据转换为分层视图模型：

Procedure2 [Mon Jan 06 00:00:00 CET 2020]
Procedure2 [Fri Jan 03 00:00:00 CET 2020]
Procedure5 [Sun Jan 05 00:00:00 CET 2020, Thu Jan 02 00:00:00 CET 2020]
Procedure1 [Sat Jan 04 00:00:00 CET 2020]
Procedure1 [Wed Jan 01 00:00:00 CET 2020]
Procedure3 [Fri Jan 03 00:00:00 CET 2020]

只需将您当前的Person和public class PersonViewModel { public CountryList CountryType { get; set; } public List<string> Names { get; set; } }分组并绑定到结果：

myList

XAML：

CountryType

Answer 2

您需要反转数据结构，诸如此类...

var countyPeople = MyList.GroupBy(p => p.CountryType)
    .Select(g => new {Country = g.Key, People = g.ToList()})
    .OrderBy(c => c.Country)
    .ToList();

然后可以将其设置为TreeView的ItemsSource。

然后，您的HierarchicalDataTemplate中的ItemsSource将绑定到此匿名类型的People属性。

将可观察的集合绑定到WPF中的TreeView

2 个答案: