基于 RadioButtons 的 C# WPF 过滤器组合框

Question

我有一个带有功能区组合框的 WPF 项目，其中显示了我尝试根据选定的 RadioButton 选项（全部、非洲、亚洲、欧洲）过滤的国家/地区列表。我的代码基于 COMBOBOX filtering in WPF with MVVM，它使用 ComboBox 选择大陆并在 ListBox 中显示过滤后的国家/地区，但我无法将其转换为使用 RadioButtons。

1. XAML isChecked="..." 行存在问题，这似乎会导致 EnumBooleanConverter 中出现“输入字符串格式不正确”错误，但如果我将它们更改为“ConverterParameter=0”，则应用程序会运行.我基于How to bind RadioButtons to an enum?。
2. 默认国家/地区列表最初显示在 ComboBox 中，但默认国家/地区不显示，而是空白。
3. 单击 RadioButton 对列表没有影响。

显然我做错了什么，但我不知道是什么。你能帮忙吗？

XAML：

<ribbon:RibbonRadioButton x:Name="AllContinents"
   GroupName="Continents"
   IsChecked="{Binding Path=SelectedRadioGroup, Converter={StaticResource EnumBooleanConverter}, ConverterParameter={x:Static local:mySettings+Continent.All}}"> <= Causes run error
</ribbon:RibbonRadioButton>

<ribbon:RibbonRadioButton x:Name="Africa"
   GroupName="Continents"
   IsChecked="{Binding Path=SelectedRadioGroup, Converter={StaticResource EnumBooleanConverter}, ConverterParameter={x:Static local:mySettings+Continent.Africa}}"> <= Causes run error
</ribbon:RibbonRadioButton>

C# 代码背后（DataContext）：

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows.Data;

public class MySettings : INotifyPropertyChanged
{
    private ObservableCollection<Country> countries;
    private ContinentViewModel selectedContinent;
    public ListCollectionView CountryView { get; set; }
    public event PropertyChangedEventHandler PropertyChanged;
    public ObservableCollection<ContinentViewModel> Continents { get; set; } 
    private static string selectedCountry = "Germany"; // Default country

    public MySettings()
    {
        countries =
            new ObservableCollection<Country>(
                new[]
                    {
                        new Country() { Continent = Continent.Africa, DisplayName = "Algeria" },
                        new Country() { Continent = Continent.Africa, DisplayName = "Egypt" },
                        new Country() { Continent = Continent.Europe, DisplayName = "France" }
                        new Country() { Continent = Continent.Europe, DisplayName = "Germany" }
                    });
        CountryView = new ListCollectionView(countries);
        CountryView.Filter = o => selectedContinent == null || ((Country)o).Continent == selectedContinent.Model;

        Continents = new ObservableCollection<ContinentViewModel>(Enum.GetValues(typeof(Continent)).Cast<Continent>().Select(c => new ContinentViewModel { Model = c}));
    }

    public ListCollectionView CountryView
    {
        get { return countryView; }
        set
        {
            countryView = value;
        }
    }

    public class Country
    {
        public string DisplayName { get; set; }
        public Continent Continent { get; set; }
    }

    public enum Continent
    {
        All,
        Africa,
        Asia,
        Europe,
        America
    }

    public class ContinentViewModel
    {
        public Continent Model { get; set; }
        public string DisplayName
        {
            get
            {
                return Enum.GetName(typeof(Continent), Model);
            }
        }
    }

    public ContinentViewModel SelectedContinent
    {
        get { return selectedContinent; }
        set
        {
            selectedContinent = value;
            OnContinentChanged();
            this.OnPropertyChanged("SelectedContinent");
        }
    }

    private void OnContinentChanged()
    {
        CountryView.Refresh();
    }

    public int SelectedRadioGroup
    {
        get { return selectedRadioGroup; }
        set
        {
            selectedRadioGroup = value;
        }
    }

    public string SelectedCountry
    {
        get { return selectedCountry; }
        set
        {
            if (selectedCountry == value) return;
            selectedCountry = value;
            OnPropertyChanged(nameof(SelectedCountry));
        }
    }

    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = this.PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

public class EnumBooleanConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
      int integer = (int)value;
      return integer == int.Parse(parameter.ToString()) ? true : (object)false;  <= Error:Input string was not in a correct format
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return ((bool)value) ? parameter : Binding.DoNothing;
    }
}

Answer 1

我会为每个单选按钮设置一个 bool 属性，而不是使用转换器。然后检查您的过滤器。

CountryView.Filter += CountryFilter;

private bool _All;
private bool _Africa;
private bool _Asia;
private bool _Europe;
private bool _America;

public bool All { get=>_All; set { _All=value; CountryView.Refresh(); } }
public bool Africa { get=> _Africa; set { _Africa=value; CountryView.Refresh(); } }
public bool Asia { get=> _Asia; set { _Asia=value; CountryView.Refresh(); } }
public bool Europe { get=> _Europe; set { _Europe=value; CountryView.Refresh(); } }
public bool America { get=> _America; set { _America=value; CountryView.Refresh() ;} }}

private bool CountryFilter(object obj)
{
    var country = obj as Country;
    if (country== null) return false;
    if (All) return true;
    if (Africa) return country.Continent == Continent.Africa;
    if (Asia) return country.Continent == Continent.Asia;
    if (Europe) return country.Continent == Continent.Europe;
    if (America) return country.Continent == Continent.America;
    return true;
}