c# - 从 ContextMenu 实现 "Rename"

Question

从 WPF 的上下文菜单中实现重命名功能的最佳方法是什么？，我想要的是像 Windows 资源管理器这样的功能，您可以在其中右键单击一个项目，获取上下文菜单，如果您选择重命名，则文本变为可编辑。

到目前为止，我已经尝试了以下方法，但我认为必须有更好的方法。几乎可以更改此解决方案的任何方面:)

<ListBox Grid.Row="0" MinWidth="200" MinHeight="75" ItemsSource="{Binding Path=DataSetsVM.DataSets, Source={StaticResource vmLocator}}" x:Name="dataSets">
<ListBox.ItemTemplate>
    <DataTemplate>
        <StackPanel x:Name="nameRoot">
            <TextBlock x:Name="nameBlock" Text="{Binding Path=Name}" HorizontalAlignment="Stretch" MinWidth="200" Tag="{Binding DataContext, ElementName=dataSets}">
            <TextBlock.ContextMenu> 
                <ContextMenu >
                    <ContextMenu.Resources>
                        <Style TargetType="Image">
                            <Setter Property="Height" Value="24"/>
                            <Setter Property="Width" Value="24"/>
                        </Style>
                    </ContextMenu.Resources>
                    <MenuItem Header="Rename" x:Name="RenameDatasetContext"
                              Command="{Binding PlacementTarget.Tag.CoreCommands.RenameDatasetCommand, RelativeSource={RelativeSource AncestorType=ContextMenu}}"
                              CommandParameter="{Binding PlacementTarget.DataContext, 
                              RelativeSource={RelativeSource FindAncestor, 
                              AncestorType={x:Type ContextMenu}}}">
                        <MenuItem.Icon>
                            <Image Source="{StaticResource RenameLargeIcon}"/>
                        </MenuItem.Icon>
                    </MenuItem>
                </ContextMenu>
            </TextBlock.ContextMenu>
            </TextBlock>
            <TextBox x:Name="nameBox"  Text="{Binding Path=Name}" HorizontalAlignment="Stretch" MinWidth="200" Visibility="Collapsed" />
        </StackPanel>
        <DataTemplate.Triggers>                                            
            <DataTrigger Binding="{Binding Path=IsEditable}" Value="True">
                <Setter TargetName="nameBlock" Property="Visibility" Value="Collapsed"/>
                <Setter TargetName="nameBox" Property="Visibility" Value="Visible"/>
            </DataTrigger>
        </DataTemplate.Triggers>
    </DataTemplate>
</ListBox.ItemTemplate> 
</ListBox>

Name 的 setter 执行此操作:

set
{
    if (IsEditable)
    {
        IsEditable = false;   
        if (_name == value)
        {
            RaisePropertyChanged(NamePropertyName);
            return;
        }
        // Do some back end stuff
        if (back end stuff worked)
        {
            var oldValue = _name;
            _name = value;
            RaisePropertyChanged(NamePropertyName);
        }
        else
        {
            // Do something about the error in the back end
        }
    }   
}

该命令所做的只是将 IsEditable 设置为 true。

除非您实际上没有更改名称，否则这将起作用，此时没有任何东西可以设置 IsEditable，因为 Name 的 setter 永远不会被调用，因此您可以在重命名模式下获得一堆项目。

我可以通过触发器在 VM 上设置属性，还是有更好的方法来做到这一点？

Answer 1

这将更像 MVVM 。后面的文件用于快速测试，所有编译/运行。

<Window x:Class="Sample.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Height="350" Width="525" 
    x:Name="wnd">

<ListBox ItemsSource="{Binding ViewModel.Items, ElementName=wnd}"
         SelectedItem="{Binding ViewModel.SelectedItem, ElementName=wnd}">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <StackPanel>
                <TextBlock x:Name="nameBlock" Text="{Binding Name}" Margin="4">
                    <TextBlock.ContextMenu> 
                        <ContextMenu>
                            <MenuItem Header="Rename" 
                                      Command="{Binding EditItemCommand}">
                            </MenuItem>
                        </ContextMenu>
                    </TextBlock.ContextMenu>
                </TextBlock>
                <TextBox x:Name="nameBox" Text="{Binding Name}" Visibility="Collapsed" Margin="2,0"/>
            </StackPanel>
            <DataTemplate.Triggers>
                <DataTrigger Binding="{Binding IsEditable}" Value="True">
                    <Setter TargetName="nameBlock" Property="Visibility" Value="Collapsed"/>
                    <Setter TargetName="nameBox" Property="Visibility" Value="Visible"/>
                </DataTrigger>
            </DataTemplate.Triggers>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

后面的代码(注意， View 是完全被动的):

public partial class MainWindow : Window
{
    public ViewModel ViewModel { get; set; }

    public MainWindow()
    {
        ViewModel = new ViewModel();
        InitializeComponent();
    }
}

viewModel(具有所有操作逻辑):

public class ViewModel : INotifyPropertyChanged
{
    private ObservableCollection<SomeClass> _items;
    private SomeClass _selectedItem;

    public ViewModel()
    {
        SelectedItem = Items.First(); 
    }

    public ObservableCollection<SomeClass> Items
    {
        get
        {
            if (_items == null)
            {
                _items = new ObservableCollection<SomeClass>();
                for (int i = 0; i < 10; i++) _items.Add(new SomeClass(string.Format("name {0}", i)));
            }

            return _items;
        }
    }

    public SomeClass SelectedItem
    {
        get { return _selectedItem; }
        set
        {
            if (_selectedItem == value)
                return;

            _selectedItem = value;

            foreach (var item in Items) item.IsEditable = false;

            RaisePropertyChanged("SelectedItem");
        }
    }

    private void RaisePropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }

    public event PropertyChangedEventHandler PropertyChanged;
}

模型(对其他模型完全愚蠢，只知道如何设置自己的行为)，其属性完全没有任何逻辑:

public class SomeClass : INotifyPropertyChanged
{
    private string _name;
    private bool _isEditable;
    private DelegateCommand _editItemCmd;

    public SomeClass(string name) { _name = name;}

    public DelegateCommand EditItemCommand
    {
        get
        {
            return _editItemCmd ?? (_editItemCmd = new DelegateCommand(() => { IsEditable = true; }));
        }
    }

    public string Name
    {
        get { return _name; }
        set
        {
            if (_name == value)
                return;
            _name = value;
            RaisePropertyChanged("Name");
        }
    }

    public bool IsEditable
    {
        get { return _isEditable; }
        set
        {
            if(_isEditable == value)
                return;
            _isEditable = value;
            RaisePropertyChanged("IsEditable");
        }
    }

    private void RaisePropertyChanged(string propertyName)
    {
        if(PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }

    public event PropertyChangedEventHandler PropertyChanged;
}