如何按DataGrid WPF上的图标编辑单元格？

<DataGrid>
    <DataGrid.Columns>
        <DataGridTemplateColumn>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <Image Source="edit_icon.png" Width="16" Height="16" Margin="0,0,5,0"/>
                        <TextBlock Text="{Binding}" />
                    </StackPanel>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
            <DataGridTemplateColumn.CellEditingTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <TextBox Text="{Binding}" />
                        <Button Content="Save" Command="{Binding SaveCommand}" />
                    </StackPanel>
                </DataTemplate>
            </DataGridTemplateColumn.CellEditingTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

public class ViewModel : INotifyPropertyChanged
{
    private ICommand _saveCommand;

    public ICommand SaveCommand
    {
        get
        {
            if (_saveCommand == null)
            {
                _saveCommand = new RelayCommand(Save);
            }
            return _saveCommand;
        }
    }

    private void Save(object parameter)
    {
        // 保存单元格的值
    }

    // INotifyPropertyChanged implementation
    // ...
}

public class ViewModel : INotifyPropertyChanged
{
    private ObservableCollection<string> _data;

    public ObservableCollection<string> Data
    {
        get { return _data; }
        set
        {
            _data = value;
            OnPropertyChanged(nameof(Data));
        }
    }

    // INotifyPropertyChanged implementation
    // ...
}

<DataGrid ItemsSource="{Binding Data}" />