WPF 自定义的DependencyProperty属性不被识别

[saybookcat]

定义了一个多选的Comobox，自定义依赖属性在调用时不被识别，不知道为什么。

public partial class MulitComboBoxUserControl : UserControl, INotifyPropertyChanged
    {
        public MulitComboBoxUserControl()
        {
            InitializeComponent();

        }

        public static readonly DependencyProperty ItemsSourceProperty =
     DependencyProperty.Register("ItemsSource", typeof(ObservableCollection<MultiComboBoxModel>), typeof(MulitComboBoxUserControl),new UIPropertyMetadata(null));


        public ObservableCollection<MultiComboBoxModel> ItemsSource
        {
            get { return (ObservableCollection<MultiComboBoxModel>)GetValue(ItemsSourceProperty); }
            set
            {
                SetValue(ItemsSourceProperty, value);
            }
        }

        public static readonly DependencyProperty SelectedItemsProperty = DependencyProperty.Register("SelectedItems", typeof(ObservableCollection<MultiComboBoxModel>), typeof(MulitComboBoxUserControl), new PropertyMetadata(null,null));

        public ObservableCollection<MultiComboBoxModel> SelectedItems
        {
            get { return (ObservableCollection<MultiComboBoxModel>)GetValue(SelectedItemsProperty); }
            set
            {
                SetValue(SelectedItemsProperty, value);
            }
        }

        private string _selectedText;
        public string SelectedText
        {
            get { return _selectedText; }
            set
            {
                _selectedText = value;
                this.NotifyPropertyChanged("SelectedText");
            }
        }




        public event PropertyChangedEventHandler PropertyChanged;

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

        private void CheckBox_Click(object sender, RoutedEventArgs e)
        {
            MultiComboBoxModel model = sender as MultiComboBoxModel;

            if (model != null)
            {
                IEnumerable<MultiComboBoxModel> items = ItemsSource.Where(b => b.IsSelected == true);
                SelectedItems = new ObservableCollection<MultiComboBoxModel>(items);
                StringBuilder builder = new StringBuilder();

                foreach (var item in items)
                {
                    builder.Append(item.Title + " ");
                }

                SelectedText = builder == null ? string.Empty : builder.ToString();
            }
        }
    }


    public class MultiComboBoxModel : INotifyPropertyChanged
    {
        private string _title;
        private bool _isSelected;

        #region Properties
        public string Title
        {
            get
            {
                return _title;
            }
            set
            {
                _title = value;
                NotifyPropertyChanged("Title");
            }
        }



        public bool IsSelected
        {
            get
            {
                return _isSelected;
            }
            set
            {
                _isSelected = value;
                NotifyPropertyChanged("IsSelected");
            }
        }

        private int _id;
        public int Id
        {
            get { return _id; }
            set
            {
                _id = value;
                this.NotifyPropertyChanged("Id");
            }
        }


        private object _tag;

        public object Tag
        {
            get { return _tag; }
            set
            {
                _tag = value;
                this.NotifyPropertyChanged("Tag");
            }
        }

        #endregion

        public event PropertyChangedEventHandler PropertyChanged;

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

    <Grid>
        <ComboBox Text="{Binding SelectedText}" IsEditable="True" ItemsSource="{Binding ItemsSource}" >
            <ComboBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <CheckBox IsChecked="{Binding IsChecked}" Click="CheckBox_Click"/>
                        <TextBlock Text="{Binding Title}"/>
                    </StackPanel>
                </DataTemplate>
            </ComboBox.ItemTemplate>
        </ComboBox>
    </Grid>

调用部分提示ItemsSource 和SelectedItems 无法识别或访问成员

<control:MulitComboBoxUserControl Grid.Row="0"  ItemsSource="{Binding ItemsSource}" SelectedItems="{Binding SelectedItems}"></control:MulitComboBoxUserControl>

[晨易夕]

我也是遇到过，之前试过取消掉 new UIPropertyMetadata(null) 默认值的参数重新编译下就正常了。

[saybookcat]

引用 1 楼 qq_28194303 的回复:

我也是遇到过，之前试过取消掉 new UIPropertyMetadata(null) 默认值的参数重新编译下就正常了。

把版本从.net framework 4.0 t提升到4.5就可以编译过了。。。。不懂为什么