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C# WPF绑定列表<；字符串>；到组合框

c# wpf

C# WPF绑定列表<；字符串>；到组合框,c#,wpf,C#,Wpf,我的问题是组合框列表为空。我浏览了很多网站（在3天内），但都没弄明白。 我已经编写了一个程序，显示学生列表，单击我可以更改他们的属性。因此，我可以成功更改除教员（组合框）之外的所有属性。 我使用了MVVM… 我有一个班的学生（模特）。这里，通用是enum学生教员 using System; using System.Collections.Generic; using System.ComponentModel; using System.Linq; using System.Text; us

我的问题是组合框列表为空。我浏览了很多网站（在3天内），但都没弄明白。
我已经编写了一个程序，显示学生列表，单击我可以更改他们的属性。因此，我可以成功更改除教员（组合框）之外的所有属性。

我使用了MVVM…
我有一个班的学生（模特）。这里，通用是enum学生教员

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

namespace _15._01._2018.Model
{
    public enum StudentFaculty { Programmer, SysAdministration, Designer};
    class Student : INotifyPropertyChanged
    {
        private string _name;
        private string _lastname;
        private StudentFaculty _faculty;
        private double _averageMark;

        public string Name
        {
            get { return _name; }
            set
            {
                if(_name == value) return;
                _name = value;
                OnPropertyChanged("Name");
            }
        }
        public string Lastname
        {
            get { return _lastname; }
            set
            {
                if (_lastname == value) return;
                _lastname = value;
                OnPropertyChanged("Lastname");
            }
        }
        public StudentFaculty Faculty
        {
            get { return _faculty; }
            set
            {
                if (_faculty == value) return;
                _faculty = value;
                OnPropertyChanged("Faculty");
            }
        }
        public double AverageMark
        {
            get { return _averageMark; }
            set
            {
                if (_averageMark == value) return;
                _averageMark = value;
                OnPropertyChanged("AverageMark");
            }
        }
        public Student() { }
        public Student(string name, string lastname, StudentFaculty faculty, double averageMark)
        {
            Name = name;
            Lastname = lastname;
            Faculty = faculty;
            AverageMark = averageMark;
        }
        public event PropertyChangedEventHandler PropertyChanged;
        public void OnPropertyChanged(string property)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(property));
        }
    }
}
类ApplicationViewModel。在这里，我从构造函数中的枚举中列出（学院），也选择了学院

using _15._01._2018.Model;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _15._01._2018.ViewModel
{
    class ApplicationViewModel : INotifyPropertyChanged
    {
        private Student _selectedStudent;
        private string _selectedFaculty;
        public ObservableCollection<Student> Students { get; set; }
        public List<string> Faculties { get; set; }
        public Student SelectedStudent
        {
            get { return _selectedStudent; }
            set
            {
                if (_selectedStudent == value) return;
                _selectedStudent = value;
                OnChangedProperty("SelectedStudent");
            }
        }
        public string SelectedFaculty
        {
            get { return _selectedFaculty; }
            set
            {
                if (_selectedFaculty == value) return;
                _selectedFaculty = value;
                OnChangedProperty("SelectedFaculty");
            }
        }
        public ApplicationViewModel()
        {
            Students = new ObservableCollection<Student>
            {
                new Student("Vova", "Zyabkin", StudentFaculty.Programmer, 9.4),
                new Student("Vadym", "Lazariev", StudentFaculty.Programmer, 9),
                new Student("SvEta", "Belyaeva", StudentFaculty.Designer, 9.8),
                new Student("Vova", "Skachkov", StudentFaculty.SysAdministration, 8.7)
            };
            Faculties = new List<string>(Enum.GetNames(typeof(StudentFaculty)));
        }
        public event PropertyChangedEventHandler PropertyChanged;
        public void OnChangedProperty(string property)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(property));
        }
    }
} 

使用_15._01._2018.Model；
使用制度；
使用System.Collections.Generic；
使用System.Collections.ObjectModel；
使用系统组件模型；
使用System.Linq；
使用系统文本；
使用System.Threading.Tasks；
名称空间_15._01._2018.ViewModel
{
类ApplicationViewModel:INotifyPropertyChanged
{
私人学生(u selected Student);；
私有字符串_selectedFaculty；
公共可观察集合学生{get；set；}
公共列表学院{get；set；}
公共学生选择学生
{
获取{return\u selectedStudent；}
设置
{
if（_selectedStudent==value）返回；
_selectedStudent=value；
一旦更改属性（“选定学生”）；
}
}
公共字符串SelectedFaculty
{
获取{return\u selectedFaculty；}
设置
{
if（_selectedFaculty==value）返回；
_selectedFaculty=值；
一旦更改属性（“选定教员”）；
}
}
公共应用程序视图模型（）
{
学生=新观察到的集合
{
新学生（“Vova”，“Zyabkin”，学生教员，程序员，9.4），
新生（“Vadym”，“Lazariev”，学生教员，程序员，9岁），
新生（“SvEta”，“Belyaeva”，学生系设计师，9.8），
新学生（“Vova”，“Skachkov”，StudentFaculty.SysAdministration，8.7）
};
学院=新列表（Enum.GetNames（typeof（StudentFaculty））；
}
公共事件属性更改事件处理程序属性更改；
公共void OnChangedProperty（字符串属性）
{
if（PropertyChanged！=null）
PropertyChanged（此，新PropertyChangedEventArgs（property））；
}
}
}
XAML
我想用字符串属性创建一个类，但它与ListBox和Student类似。

首先，ComboBox的DataContext设置为SelectedStudent，而不是ApplicationViewModel（请参见父StackPanel）。其次，Faculties属性返回字符串列表，但Student类的属性为StudentFaculty（为SelectedValue绑定将不起作用）

请尝试以下操作：

模型/视图模型：

class ApplicationViewModel : INotifyPropertyChanged
{
    private Student _selectedStudent;
    private StudentFaculty _selectedFaculty;
    public ObservableCollection<Student> Students { get; set; }
    public ObservableCollection<StudentFaculty> Faculties { get; set; }
    public Student SelectedStudent
    {
        get => _selectedStudent;
        set
        {
            if (_selectedStudent == value) return;
            _selectedStudent = value;
            OnChangedProperty("SelectedStudent");
        }
    }
    public StudentFaculty SelectedFaculty
    {
        get => _selectedFaculty;
        set
        {
            if (_selectedFaculty == value) return;
            _selectedFaculty = value;
            OnChangedProperty("SelectedFaculty");
        }
    }
    public ApplicationViewModel()
    {
        Students = new ObservableCollection<Student>
        {
            new Student("Vova", "Zyabkin", StudentFaculty.Programmer, 9.4),
            new Student("Vadym", "Lazariev", StudentFaculty.Programmer, 9),
            new Student("SvEta", "Belyaeva", StudentFaculty.Designer, 9.8),
            new Student("Vova", "Skachkov", StudentFaculty.SysAdministration, 8.7)
        };
        Faculties = new ObservableCollection<StudentFaculty>(Enum.GetValues(typeof(StudentFaculty)).OfType<StudentFaculty>());
    }
    public event PropertyChangedEventHandler PropertyChanged;

    public void OnChangedProperty(string property) => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(property));
}

public enum StudentFaculty { Programmer, SysAdministration, Designer };
class Student : INotifyPropertyChanged
{
    private string _name;
    private string _lastname;
    private StudentFaculty _faculty;
    private double _averageMark;

    public string Name
    {
        get => _name;
        set
        {
            if (_name == value) return;
            _name = value;
            OnPropertyChanged("Name");
        }
    }
    public string Lastname
    {
        get => _lastname;
        set
        {
            if (_lastname == value) return;
            _lastname = value;
            OnPropertyChanged("Lastname");
        }
    }
    public StudentFaculty Faculty
    {
        get => _faculty;
        set
        {
            if (_faculty == value) return;
            _faculty = value;
            OnPropertyChanged("Faculty");
        }
    }
    public double AverageMark
    {
        get => _averageMark;
        set
        {
            if (_averageMark == value) return;
            _averageMark = value;
            OnPropertyChanged("AverageMark");
        }
    }
    public Student() { }
    public Student(string name, string lastname, StudentFaculty faculty, double averageMark)
    {
        Name = name;
        Lastname = lastname;
        Faculty = faculty;
        AverageMark = averageMark;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(string property) => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(property));
}

class ApplicationViewModel:INotifyPropertyChanged
{
私人学生(u selected Student);；
私立学生学院(u选择的学院),；
公共可观察集合学生{get；set；}
公共可观测集合能力{get；set；}
公共学生选择学生
{
get=>\u selectedStudent；
设置
{
if（_selectedStudent==value）返回；
_selectedStudent=value；
一旦更改属性（“选定学生”）；
}
}
公共学生教员选定教员
{
get=>\u选择的教员；
设置
{
if（_selectedFaculty==value）返回；
_selectedFaculty=值；
一旦更改属性（“选定教员”）；
}
}
公共应用程序视图模型（）
{
学生=新观察到的集合
{
新学生（“Vova”，“Zyabkin”，学生教员，程序员，9.4），
新生（“Vadym”，“Lazariev”，学生教员，程序员，9岁），
新生（“SvEta”，“Belyaeva”，学生系设计师，9.8），
新学生（“Vova”，“Skachkov”，StudentFaculty.SysAdministration，8.7）
};
Faculties=新的ObservableCollection（Enum.GetValues（typeof（StudentFaculty））.OfType（））；
}
公共事件属性更改事件处理程序属性更改；
public void OnChangedProperty（string属性）=>PropertyChanged？.Invoke（这是新的PropertyChangedEventArgs（属性））；
}
公共enum学生学院{程序员、系统管理、设计师}；
班级学生：INotifyPropertyChanged
{
私有字符串\u名称；
私有字符串_lastname；
私立学生学院；
私人双平均柜；
公共字符串名
{
get=>\u name；
设置
{
if（_name==value）返回；
_名称=值；
不动产变更（“名称”）；
}
}
公共字符串姓氏
{
get=>\u lastname；
设置
{
if（_lastname==value）返回；
_lastname=值；
OnPropertyChanged（“姓氏”）；
}
}
公立学生学院
{
get=>\U教员；
设置
{
if（_=value）返回；
_能力=价值；
关于财产变更（“教员”）；
}
}
公共双平均柜
{
get=>\u averageMark；
设置
{
如果（_averageMark==值）re

class ApplicationViewModel : INotifyPropertyChanged
{
    private Student _selectedStudent;
    private StudentFaculty _selectedFaculty;
    public ObservableCollection<Student> Students { get; set; }
    public ObservableCollection<StudentFaculty> Faculties { get; set; }
    public Student SelectedStudent
    {
        get => _selectedStudent;
        set
        {
            if (_selectedStudent == value) return;
            _selectedStudent = value;
            OnChangedProperty("SelectedStudent");
        }
    }
    public StudentFaculty SelectedFaculty
    {
        get => _selectedFaculty;
        set
        {
            if (_selectedFaculty == value) return;
            _selectedFaculty = value;
            OnChangedProperty("SelectedFaculty");
        }
    }
    public ApplicationViewModel()
    {
        Students = new ObservableCollection<Student>
        {
            new Student("Vova", "Zyabkin", StudentFaculty.Programmer, 9.4),
            new Student("Vadym", "Lazariev", StudentFaculty.Programmer, 9),
            new Student("SvEta", "Belyaeva", StudentFaculty.Designer, 9.8),
            new Student("Vova", "Skachkov", StudentFaculty.SysAdministration, 8.7)
        };
        Faculties = new ObservableCollection<StudentFaculty>(Enum.GetValues(typeof(StudentFaculty)).OfType<StudentFaculty>());
    }
    public event PropertyChangedEventHandler PropertyChanged;

    public void OnChangedProperty(string property) => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(property));
}

public enum StudentFaculty { Programmer, SysAdministration, Designer };
class Student : INotifyPropertyChanged
{
    private string _name;
    private string _lastname;
    private StudentFaculty _faculty;
    private double _averageMark;

    public string Name
    {
        get => _name;
        set
        {
            if (_name == value) return;
            _name = value;
            OnPropertyChanged("Name");
        }
    }
    public string Lastname
    {
        get => _lastname;
        set
        {
            if (_lastname == value) return;
            _lastname = value;
            OnPropertyChanged("Lastname");
        }
    }
    public StudentFaculty Faculty
    {
        get => _faculty;
        set
        {
            if (_faculty == value) return;
            _faculty = value;
            OnPropertyChanged("Faculty");
        }
    }
    public double AverageMark
    {
        get => _averageMark;
        set
        {
            if (_averageMark == value) return;
            _averageMark = value;
            OnPropertyChanged("AverageMark");
        }
    }
    public Student() { }
    public Student(string name, string lastname, StudentFaculty faculty, double averageMark)
    {
        Name = name;
        Lastname = lastname;
        Faculty = faculty;
        AverageMark = averageMark;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(string property) => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(property));
}



<Window x:Class="WpfApp4.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:converters="clr-namespace:WpfApp4.Views.Converters"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
    xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"
    xmlns:viewModels="clr-namespace:WpfApp4.ViewModels"
    mc:Ignorable="d"
    Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
    <viewModels:ApplicationViewModel />
</Window.DataContext>
<Window.Resources>
    <Style TargetType="TextBlock">
        <Setter Property="FontSize" Value="14" />
    </Style>
    <Style TargetType="TextBox">
        <Setter Property="FontSize" Value="14" />
    </Style>
    <CollectionViewSource x:Key="Faculties" Source="{Binding Faculties}"></CollectionViewSource>
</Window.Resources>
<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition></ColumnDefinition>
        <ColumnDefinition></ColumnDefinition>
    </Grid.ColumnDefinitions>
    <ListBox ItemsSource="{Binding Students}" SelectedItem="{Binding SelectedStudent}">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel Orientation="Vertical">
                    <TextBlock Text="{Binding Path=Name}"></TextBlock>
                    <TextBlock Text="{Binding Path=Lastname}"></TextBlock>
                    <!--<TextBlock Text="{Binding Path=Faculty}"></TextBlock>-->
                    <TextBlock Text="{Binding Path=AverageMark}"></TextBlock>
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
    <Grid Grid.Column="1">
        <StackPanel DataContext="{Binding SelectedStudent}">
            <TextBlock Text="D A T A"></TextBlock>
            <TextBlock Text="Name:"></TextBlock>
            <TextBox Text="{Binding Name, UpdateSourceTrigger=PropertyChanged}"></TextBox>
            <TextBlock Text="Lastname:"></TextBlock>
            <TextBox Text="{Binding Lastname, UpdateSourceTrigger=PropertyChanged}"></TextBox>
            <TextBlock Text="Faculty:"></TextBlock>
            <ComboBox ItemsSource="{Binding Source={StaticResource Faculties}}" SelectedValue="{Binding Faculty, Mode=TwoWay}">

            </ComboBox>
            <TextBlock Text="Average Mark:"></TextBlock>
            <TextBox Text="{Binding AverageMark, UpdateSourceTrigger=PropertyChanged}"></TextBox>
        </StackPanel>
    </Grid>
</Grid>