使用 MVVM 绑定 WPF DataGridComboBoxColumn [英] Binding a WPF DataGridComboBoxColumn with MVVM

问题描述

我查看了各种的答案 问题，但尚未设法将内容映射到我遇到的问题的答案中试图解决.我已将其简化为以下代码(代表我试图实现的结果)，并且基本上希望能够将 Person.TitleId 呈现为其相应的 Title.TitleText 当该行未被编辑时，并正确绑定下拉列表，以便在下拉列表中显示 TitleText 并写入关联的 TitleId 在更改时返回 Person 记录.

I've looked at the answers to various questions, but haven't managed to map the content in the answers to the problem I'm attempting to solve. I've reduced it down to the following code (representative of the outcome I'm trying to achieve), and basically want to be able to render the Person.TitleId as its corresponding Title.TitleText when the row isn't being edited, and have the drop-down bound correctly so that it displays the TitleTexts in the drop-down and writes the associated TitleId back to the Person record when its changed.

简而言之，我在 中放了什么来实现这一点?

In short, what do I put in my <DataGridComboBoxColumn> to achieve this?

App.xaml.cs

App.xaml.cs

protected override void OnStartup(StartupEventArgs e)
{
    base.OnStartup(e);

    var viewModel = new ViewModels.MainWindowViewModel();
    var mainWindow = new MainWindow();
    mainWindow.DataContext = viewModel;
    mainWindow.ShowDialog();
}

主窗口.xaml

<Grid>
    <DataGrid AutoGenerateColumns="False" ItemsSource="{Binding Path=Contacts}">
        <DataGrid.Columns>
            <DataGridComboBoxColumn Header="Title" SelectedItemBinding="{Binding Person}">
                <DataGridComboBoxColumn.ElementStyle>
                    <Style TargetType="ComboBox">
                        <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.Titles}"/>
                        <Setter Property="IsReadOnly" Value="True"/>
                    </Style>
                </DataGridComboBoxColumn.ElementStyle>
                <DataGridComboBoxColumn.EditingElementStyle>
                    <Style TargetType="ComboBox">
                        <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.Titles}"/>
                        <Setter Property="DisplayMemberPath" Value="TitleText" />
                    </Style>
                </DataGridComboBoxColumn.EditingElementStyle>
            </DataGridComboBoxColumn>
        </DataGrid.Columns>
    </DataGrid>
</Grid>

Person.cs

public class Person
{
    public int TitleId { get; set; }
    public string LastName { get; set; }
    public string FirstName { get; set; }
}

标题.cs

public struct Title
{
    public Title(int titleId, string titleText)
        : this()
    {
        TitleId = titleId;
        TitleText = titleText;
    }

    public string TitleText { get; private set; }
    public int TitleId { get; private set; }

    public static List<Title> GetAvailableTitles()
    {
        var titles = new List<Title>();

        titles.Add(new Title(1, "Mr"));
        titles.Add(new Title(2, "Miss"));
        titles.Add(new Title(3, "Mrs"));

        return titles;
    }
}

MainWindowViewModel.cs

MainWindowViewModel.cs

public class MainWindowViewModel : ViewModelBase
{
    private ObservableCollection<Person> contacts;
    private List<Title> titles;

    public MainWindowViewModel()
    {
        titles = Title.GetAvailableTitles();

        Contacts = new ObservableCollection<Person>();
        Contacts.Add(new Person() { FirstName = "Jane", LastName = "Smith", TitleId = 2 });
    }

    public List<Title> Titles
    {
        get { return titles; }
    }

    public ObservableCollection<Person> Contacts
    {
        get { return contacts; }
        set
        {
            if (contacts != value)
            {
                contacts = value;
                this.OnPropertyChanged("Contacts");
            }
        }
    }
}

ViewModelBase.cs

ViewModelBase.cs

public class ViewModelBase : INotifyPropertyChanged
{
    protected void OnPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }

    public event PropertyChangedEventHandler PropertyChanged;
}

推荐答案

这是一个工作代码.这里的关键点是使用SelectedValueBinding 而不是SelecteItemBinding.

Here is a working code. The key point here was to use SelectedValueBinding instead of SelecteItemBinding.

<DataGridComboBoxColumn Header="Title" 
                        SelectedValueBinding="{Binding TitleId}"
                        SelectedValuePath="TitleId"
                        DisplayMemberPath="TitleText"
                        >
    <DataGridComboBoxColumn.ElementStyle>
        <Style TargetType="ComboBox">
            <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.Titles}"/>
        </Style>
    </DataGridComboBoxColumn.ElementStyle>
    <DataGridComboBoxColumn.EditingElementStyle>
        <Style TargetType="ComboBox">
            <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.Titles}"/>
        </Style>
    </DataGridComboBoxColumn.EditingElementStyle>
</DataGridComboBoxColumn>

这篇关于使用 MVVM 绑定 WPF DataGridComboBoxColumn的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！