WPF

Question

我正在编写一个应用程序，遇到了一个显示来自视图模型的项目的 ListView 的问题；在所述视图模型“Selected”中有一个属性，它只是一个布尔值，我将其绑定到 ListView 的“IsSelected”属性。

我有一个“清除选择”按钮，它会遍历 selected 的每个项目并将其设置为 false；这有效并且命令已更新并且按钮不再启用，因为 Selected == true.

没有任何内容

图片中

项目已 selected；按钮可用。

“清除选择”按钮已按下

此时，我无法再单击控件 select 元素；我必须控制单击它以取消 select 它，这会使所有内容恢复为禁用状态并且没有 selected.

这是控件的 XAML - 不确定我做错了什么，但到目前为止我找不到答案。

<ListView ItemsSource="{Binding AssignableItems, UpdateSourceTrigger=PropertyChanged}" Grid.Row="2" SelectionMode="Extended">
    <ListView.ItemContainerStyle>
        <Style TargetType="ListViewItem" BasedOn="{StaticResource lviStyleBase}">
            <Setter Property="IsSelected" Value="{Binding Selected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
        </Style>
    </ListView.ItemContainerStyle>
    <ListView.View>
        <GridView>
            <GridViewColumn Header="Created" DisplayMemberBinding="{Binding ContactCreated}" Width="Auto" />
            <GridViewColumn Header="Contact Name" DisplayMemberBinding="{Binding ContactName}" Width="Auto" />
            <GridViewColumn Header="Company" DisplayMemberBinding="{Binding Company}" Width="Auto" />
        </GridView>
    </ListView.View>
</ListView>

这是视图模型：

namespace CSI.ViewModels
{
    public class AssignViewModel
        : ModelBase
    {
        #region Properties
        private bool viewingFilters;

        public bool Filtering
        {
            get { return viewingFilters; }
            set { if ( SetValue(ref viewingFilters, value) ) Notify(); }
        }

        private bool assigning;

        public bool Assigning
        {
            get { return assigning; }
            set { if ( SetValue(ref assigning, value) ) Notify(); }
        }

        private string viewTitle = "Assign";
        public string ViewTitle
        {
            get => $"{viewTitle}{(Filtered ? " (filtered)" : "")}";
        }

        private AssignFilterValuesModel filters;

        public AssignFilterValuesModel Filters
        {
            get { return filters; }
            set { SetValue(ref filters, value); }
        }

        public bool Filtered
        {
            get
            {
                if ( filters == null ) return false;

                return assignables.Count() != AssignableItems.Count();
            }
        }

        private bool loading;

        public bool Loading
        {
            get { return loading; }
            set { SetValue(ref loading, value); }
        }

        private ObservableCollection<AssignableWorkItemModel> assignables;
        public ObservableCollection<AssignableWorkItemModel> AssignableItems
        {
            get
            {
                if ( assignables == null ) return null;
                if ( Filters == null ) return assignables;

                var retval = assignables.Where(x => 1 == 1);

                if ( Filters.Dealers.Any(x => x.Selected) )
                    retval = retval.Where(x => filters.Dealers.Where(o => o.Selected).Select(o => o.Key).ToList().Contains(x.Dealer));

                if ( Filters.VehicleModels.Any(x => x.Selected) )
                    retval = retval.Where(x => filters.VehicleModels.Where(o => o.Selected).Select(o => o.Key).ToList().Contains(x.VehicleModel));

                return new ObservableCollection<AssignableWorkItemModel>(retval);
            }
            set => SetValue(ref assignables, value);
        }
        private ObservableCollection<AssignableWorkItemModel> selected;
        public ObservableCollection<AssignableWorkItemModel> SelectedItems
        {
            get => selected;
            set => SetValue(ref selected, value);
        }
        #endregion
        #region Commands
        private RelayCommand displayFilterScreen;
        public void Execute_DisplayFilters(object _)
        {
            Filtering = true;
        }
        public bool CanExecute_DisplayFilters(object _) => !Filtering;
        public RelayCommand DisplayFilters
        {
            get => displayFilterScreen ?? (displayFilterScreen = new RelayCommand(Execute_DisplayFilters, CanExecute_DisplayFilters));
        }

        private RelayCommand applyFilters;
        public void Execute_ApplyFilters(object _)
        {
            Filtering = !Filtering;
            Notify(nameof(AssignableItems));
            Notify(nameof(Filtered));
            Notify(nameof(ViewTitle));
        }
        public bool CanExecute_ApplyFilters(object _) => Filtering;
        public RelayCommand ApplyFilters
        {
            get => applyFilters ?? (applyFilters = new RelayCommand(Execute_ApplyFilters, CanExecute_ApplyFilters));
        }

        private RelayCommand doAssign;
        public void Execute_Assign(object _)
        {
            UserSelectWindow us = new UserSelectWindow();
            us.Owner = Application.Current.MainWindow;

            ViewModelServer.UserSelectVM.Prompt = "Select the user you wish to assign these items to";
        }
        public bool CanExecute_Assign(object _) => !Filtering && (bool)AssignableItems?.Any(x => x.Selected);
        public RelayCommand Assign
        {
            get => doAssign ?? (doAssign = new RelayCommand(Execute_Assign, CanExecute_Assign));
        }

        private RelayCommand clrSelection;
        public void Execute_ClearSelection(object _)
        {
            AssignableItems?.Where(x => x.Selected).ToList().ForEach(x => x.Selected = false);
        }
        public bool CanExecute_ClearSelection(object _) => (bool)AssignableItems?.Any(x => x.Selected);
        public RelayCommand ClearSelection
        {
            get => clrSelection ?? (clrSelection = new RelayCommand(Execute_ClearSelection, CanExecute_ClearSelection));
        }
        #endregion
        #region Constructors
        
        #endregion
    }
}

Answer 1

解决方法是为SelectedIndex添加绑定，调用ClearSelection时将其值设置为-1；来自 here

的小费

WPF - 刷新绑定到 ViewModel 的 ListView

WPF - Refresh ListView bound to ViewModel

listview

mvvm

listviewitem