我知道这很长,但请耐心等待。
我使用 MVVM light 框架在 MVVM light samples 中创建了一个与 Laurent Bugnion 的“MyFriends”程序非常相似的 Windows 应用程序商店程序。
在他的程序中,他使用 gridview 的 SelectedItem 属性来跟踪哪个项目是所选项目。
问题是,我让用户能够在 GridView 上选择多个项目,然后使用 App Bar 上的按钮对其进行操作。对于这个 SelectedItem 将不起作用。
有谁知道如何使用多选 GridView 进行这项工作?我已经根据 WPF 上的一些文章尝试了 GridViewItem 的 IsSelected 属性,但这似乎不起作用。 SelectedTimesheets getter 在调用时总是返回空的。这是我目前所拥有的:
MainPage.xaml(绑定(bind)到具有子 TimesheetViewModel 可观察集合的 MainViewModel):
<GridView
x:Name="itemGridView"
IsItemClickEnabled="True"
ItemsSource="{Binding Timesheets}"
ItemTemplate="{StaticResource TimesheetTemplate}"
Margin="10"
Grid.Column="0"
SelectionMode="Multiple"
helpers:ItemClickCommand.Command="{Binding NavigateTimesheetCommand}" RenderTransformOrigin="0.738,0.55" >
<GridView.ItemContainerStyle>
<Style TargetType="GridViewItem">
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}"/>
</Style>
</GridView.ItemContainerStyle>
</GridView>
MainViewModel(从完整代码中删减):
public class MainViewModel : ViewModelBase
{
private readonly IDataService _dataService;
private readonly INavigationService _navigationService;
/// <summary>
/// Initializes a new instance of the MainViewModel class.
/// </summary>
public MainViewModel(IDataService dataService, INavigationService navigationService)
{
_dataService = dataService;
_navigationService = navigationService;
Timesheets = new ObservableCollection<TimesheetViewModel>();
ExecuteRefreshCommand();
}
public ObservableCollection<TimesheetViewModel> Timesheets
{
get;
private set;
}
public IEnumerable<TimesheetViewModel> SelectedTimesheets
{
get { return Timesheets.Where(o => o.IsSelected); }
}
private async void ExecuteRefreshCommand()
{
var timesheets = await _dataService.GetTimesheets("domain\\user");
if (timesheets != null)
{
Timesheets.Clear();
foreach (var timesheet in timesheets)
{
Timesheets.Add(new TimesheetViewModel(timesheet));
}
}
}
}
时间 TableView 模型:
public class TimesheetViewModel: ViewModelBase
{
public bool IsSelected { get; set; }
public Timesheet Model
{
get;
private set;
}
public TimesheetViewModel(Timesheet model)
{
Model = model;
}
}
如果我手动设置 IsSelected 属性,则 SelectedTimesheets lambda 起作用,因此问题出在 XAML 与 IsSelected 属性的绑定(bind)中。
如有任何帮助,我们将不胜感激。
最佳答案
当然,我知道你的意思。太糟糕了,这不是自动的,但事实并非如此。该解决方案涉及一个简单的自定义 GridView
,它继承自 GridView
。没有什么太疯狂的,也就是说,如果你让它沉入其中。这是代码,我刚刚测试过它:
这是您的 XAML:
<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
<Grid.ColumnDefinitions >
<ColumnDefinition />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<local:MyGridView ItemsSource="{Binding Items}" SelectionMode="Multiple"
BindableSelectedItems="{Binding Selected}" />
<local:MyGridView Grid.Column="1" ItemsSource="{Binding Selected}" />
</Grid>
这是您的 View 模型( super 简化):
public class ViewModel
{
ObservableCollection<string> m_Items
= new ObservableCollection<string>(Enumerable.Range(1, 100).Select(x => x.ToString()));
public ObservableCollection<string> Items { get { return m_Items; } }
ObservableCollection<object> m_Selected = new ObservableCollection<object>();
public ObservableCollection<object> Selected { get { return m_Selected; } }
}
这是您的自定义 GridView :
public class MyGridView : GridView
{
public ObservableCollection<object> BindableSelectedItems
{
get { return GetValue(BindableSelectedItemsProperty) as ObservableCollection<object>; }
set { SetValue(BindableSelectedItemsProperty, value as ObservableCollection<object>); }
}
public static readonly DependencyProperty BindableSelectedItemsProperty =
DependencyProperty.Register("BindableSelectedItems",
typeof(ObservableCollection<object>), typeof(MyGridView),
new PropertyMetadata(null, (s, e) =>
{
(s as MyGridView).SelectionChanged -= (s as MyGridView).MyGridView_SelectionChanged;
(s as MyGridView).SelectionChanged += (s as MyGridView).MyGridView_SelectionChanged;
}));
void MyGridView_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (BindableSelectedItems == null)
return;
foreach (var item in BindableSelectedItems.Where(x => !this.SelectedItems.Contains(x)).ToArray())
BindableSelectedItems.Remove(item);
foreach (var item in this.SelectedItems.Where(x => !BindableSelectedItems.Contains(x)))
BindableSelectedItems.Add(item);
}
}
只有一个新属性 BindableSelectedItems
。
祝你好运!
关于c# - 在 Windows App Store Gridview 中迭代选定的项目,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/18359366/