更改datagridcombobox單元格值后，如何在WPF datagridtextcolumn單元格中設置值？

Question

我正在使用WPF 4.0 Datagrid開發應用程序。 我的Datagrid網格具有一個datagridcombobox列和一個datagridtext列。 如何使用datagridcomboboxcolumn的SelectedIndex_Changed事件更改datagrid文本單元格值？

Answer 1

我建議使用MVVM方法創建WPF應用程序。 通常，這意味着您將停止處理離散事件（如SelectedIndex_Changed ，而是綁定到ViewModel（VM）和/或Model（M）中的可觀察對象。

使用這種體系結構，解決問題很容易。 只需將DataGridComboBoxColumn的SelectedItemBinding綁定到DataGrid的ItemSource對象的屬性即可。 然后，將您的DataGridTextColumn綁定到該屬性。 這在代碼中有更好的解釋：

視圖：

<!-- Previous Window XAML omitted, but you must set it's DataContext to the ViewModel -->
<DataGrid
    CanUserAddRows="False"
    AutoGenerateColumns="False"
    ItemsSource="{Binding People}"
    >
    <DataGrid.Columns>
        <DataGridTextColumn
            Header="Selected Name"
            Binding="{Binding Name}"
            />
        <DataGridComboBoxColumn
            Header="Available Names"
            SelectedItemBinding="{Binding Name}"
            >
            <DataGridComboBoxColumn.ElementStyle>
                <Style TargetType="{x:Type ComboBox}">
                    <Setter Property="ItemsSource" Value="{Binding Names}" />
                </Style>
            </DataGridComboBoxColumn.ElementStyle>
            <DataGridComboBoxColumn.EditingElementStyle>
                <Style TargetType="{x:Type ComboBox}">
                    <Setter Property="ItemsSource" Value="{Binding Names}" />
                </Style>
            </DataGridComboBoxColumn.EditingElementStyle>
        </DataGridComboBoxColumn>
    </DataGrid.Columns>
</DataGrid>

ViewModel：

internal class MainWindowViewModel : ViewModelBase
{
    private ObservableCollection<Person> _people;
    public ObservableCollection<Person> People
    {
        get
        {
            _people = _people ?? new ObservableCollection<Person>()
            {
                new Person(),
                new Person(),
                new Person(),
            };

            return _people;
        }
    }
}

模型：

internal class Person : INotifyPropertyChanged
{
    private static ObservableCollection<string> _names = new ObservableCollection<string>()
    {
        "Chris",
        "Steve",
        "Pete",
    };

    public ObservableCollection<string> Names
    {
        get { return _names; }
    }

    private string _name;
    public string Name
    {
        get { return _name; }
        set
        {
            if (_name != value)
            {
                _name = value;
                this.RaisePropertyChanged(() => this.Name);
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void RaisePropertyChanged<T>(Expression<Func<T>> expr)
    {
        var memberExpr = expr.Body as MemberExpression;

        if (memberExpr != null)
        {
            var handler = this.PropertyChanged;
            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(memberExpr.Member.Name));
            }
        }
        else
        {
            throw new ArgumentException(String.Format("'{0}' is not a valid expression", expr));
        }
    }
}