DataGridTemplateColumn ComboBox结合

Question

我有一个绑定到一组员工的DataGrid。Employee类具有类型为Country的EmployeeCountry。国家类型由CountryId和CountryName组成。

我有以下XAML：

     <DataGrid ItemsSource="{Binding EmployeeList}" CanUserAddRows="True">
            <DataGrid.Columns>
                <DataGridTemplateColumn Header="CountryCombo2">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <ComboBox ItemsSource="{Binding Path=DataContext.CountryList, RelativeSource={RelativeSource AncestorType={x:Type Window}}}" 
                                      DisplayMemberPath="CountryName" />
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
            </DataGrid.Columns>
        </DataGrid>

EmployeeList和CountryList是ViewModel上的ObservableCollection属性，ViewModel是包含DataGrid的窗口的DataContext。我能够用ComboBox填充CountryList。

问题:我需要弄清楚如何设置ComboBox的其他属性，如SelectedValuePath、SelectedItem等，以便DataGrid的每一行都正确地在ComboBox中显示适当的EmployeeCountry。如果员工的EmployeeCountry属性为NULL，则ComboBox不应选择任何项。

更新：即使CanUserAddRows属性设置为true，也无法向DataGrid添加新行。

Answer 1

我能够用我在其中一个评论中提到的问题来解决我的关切。只是发布了帮助它正常工作的XAML：

 <DataGrid ItemsSource="{Binding EmployeeList}" CanUserAddRows="True" AutoGenerateColumns="False" Margin="0,0,0,90">
        <DataGrid.Columns>
            <DataGridTemplateColumn Header="CountryCombo2">
                <DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
                        <ComboBox ItemsSource="{Binding Path=DataContext.CountryList, RelativeSource={RelativeSource AncestorType={x:Type Window}}}" 
                                      DisplayMemberPath="CountryName" 
                                      SelectedItem="{Binding EmployeeCountry, Mode=TwoWay}"
                                      SelectedValue="{Binding EmployeeCountry.CountryId}"
                                      SelectedValuePath="CountryId" />
                    </DataTemplate>
                </DataGridTemplateColumn.CellTemplate>
            </DataGridTemplateColumn>
        </DataGrid.Columns>
    </DataGrid>

Answer 2

我会做这样的事

 <ComboBox SelectedValuePath="CountryName" SelectedItem="{Binding Country}"  ItemsSource="{Binding Path=DataContext.CountryList, RelativeSource={RelativeSource AncestorType={x:Type Window}}}">

为了向你们展示我给你们的作品，我把所有的代码都写好了。

public class Employees :INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged([CallerMemberName]string propertyName = null)
    {
        var handler = PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }

    private string _name;
    public string Name
    {
        get
        {
            return _name; 
        }

        set
        {
            if (_name == value)
                return;
            _name = value;
            OnPropertyChanged();
        }
    }

    private Country _employeeCountry;
    public Country EmployeeCountry
    {
        get
        {
            return _employeeCountry;
        }

        set
        {
            if (_employeeCountry == value)
                return;
            _employeeCountry = value;
            OnPropertyChanged();
        }
    }
}

public class Country
{
    private string _name;
    public string Name
    {
        get
        {
            return _name;
        }

        set
        {
            if (_name == value)
                return;
            _name = value;
        }
    }
}

private static ObservableCollection<Country> _countryList = new ObservableCollection<Country>(new []{ new Country{Name="US"}, new Country{Name="UK"}});

public ObservableCollection<Country> CountryList
{
    get
    {
        return _countryList;
    }
}

private ObservableCollection<Employees> _employeeList = new ObservableCollection<Employees>(new[] { new Employees { Name = "Ty", EmployeeCountry = _countryList.First() }, new Employees { Name = "Dude" } });

public ObservableCollection<Employees> EmployeeList
{
    get
    {
        return _employeeList;
    }
}

和Xaml

<DataGrid ItemsSource="{Binding EmployeeList}" CanUserAddRows="True">
        <DataGrid.Columns>
            <DataGridTemplateColumn Header="CountryCombo2">
                <DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
                        <ComboBox ItemsSource="{Binding Path=CountryList, RelativeSource={RelativeSource AncestorType={x:Type Window}}}" DisplayMemberPath="Name"
                                 SelectedValuePath="Name" SelectedItem="{Binding EmployeeCountry}" />
                    </DataTemplate>
                </DataGridTemplateColumn.CellTemplate>
            </DataGridTemplateColumn>
        </DataGrid.Columns>
    </DataGrid>