我正在按照此帖Pagination in WPF中的建议实现分页数据网格。一切正常,但我的网格中有一些复选框,当我尝试检查它们时,应用程序抛出异常,因为CollectionView
不允许编辑。如何获取当前视图中的项目列表并将其转换为列表集合?我在public class PagingCollectionView : CollectionView
类中添加了以下方法进行测试:
private void RefreshGrid()
{
//this._currentDataGrid.DataContext = this; **throws exception** when clicking on
//this.Refresh(); **checkbox
List<Customer> list = this.Cast<Customer>().ToList(); //** still get the original list
this._currentDataGrid.DataContext = list;
this.Refresh();
//I also tried this
//this.Refresh();
//List<Customer> list = this.Cast<Customer>().ToList(); //** same result
//this._currentDataGrid.DataContext = list;
}
理想情况下,我想获取视图中的项目,此时我将每页的项目设置为5,但我得到了所有16项。 PagingCollectionView
工作正常,但我无法检查框。
答案 0 :(得分:3)
来自关联帖子的PagingCollectionView
未实现IEditableCollectionView
,因此您无法更改网格中的值。
不幸的是,WPF中似乎没有标准的分页集合视图。但是Silverlight的PagedCollectionView
确实有效,只需将该代码复制到您的项目中即可。我想您也可以安装Silverlight SDK并添加对System.Windows.Data.dll的引用。或者,如果您可以自己实施IEditableCollectionView
,我相信您会找到一些参与者;)。
对于看起来最合适的内容,您需要this page中的所有代码。
测试输出:
视图模型:
using System;
using System.Collections.ObjectModel;
using System.Windows.Data;
using System.Windows.Input;
namespace WpfApplication1.ViewModels
{
public class CustomersViewModel : NotifyBase // replace NotifyBase by implementing INotifyPropertyChanged
{
public PagedCollectionView CustomerCollection { get; private set; }
public int TotalPages { get { return (int)Math.Ceiling((double)CustomerCollection.ItemCount / (double)CustomerCollection.PageSize); } }
public int PageNumber { get { return CustomerCollection.PageIndex + 1; } }
public ICommand MoveNextCommand { get { return GetValue(() => MoveNextCommand); } set { SetValue(() => MoveNextCommand, value); } }
public ICommand MovePreviousCommand { get { return GetValue(() => MovePreviousCommand); } set { SetValue(() => MovePreviousCommand, value); } }
public CustomersViewModel()
{
this.CustomerCollection = new PagedCollectionView(new ObservableCollection<Customer>
{
new Customer(true, "Michael", "Delaney"),
new Customer(false, "James", "Ferguson"),
new Customer(false, "Andrew", "McDonnell"),
new Customer(true, "Sammie", "Hunnery"),
new Customer(true, "Olivia", "Tirolio"),
new Customer(false, "Fran", "Rockwell"),
new Customer(false, "Andrew", "Renard"),
});
this.CustomerCollection.PageSize = 3;
this.MoveNextCommand = new ActionCommand(MoveNext);
this.MovePreviousCommand = new ActionCommand(MovePrevious);
}
private void MoveNext()
{
this.CustomerCollection.MoveToNextPage();
OnPropertyChanged("PageNumber");
}
private void MovePrevious()
{
this.CustomerCollection.MoveToPreviousPage();
OnPropertyChanged("PageNumber");
}
}
public class Customer : NotifyBase // replace NotifyBase by implementing INotifyPropertyChanged
{
public bool IsActive { get { return GetValue(() => IsActive); } set { SetValue(() => IsActive, value); } }
public string FirstName { get { return GetValue(() => FirstName); } set { SetValue(() => FirstName, value); } }
public string LastName { get { return GetValue(() => LastName); } set { SetValue(() => LastName, value); } }
public Customer(bool isActive, string firstName, string lastName)
{
this.IsActive = isActive;
this.FirstName = firstName;
this.LastName = lastName;
}
}
public class ActionCommand : ICommand
{
public event EventHandler CanExecuteChanged;
private Action _action;
public ActionCommand(Action action)
{
_action = action;
}
public bool CanExecute(object parameter) { return true; }
public void Execute(object parameter)
{
if (_action != null)
_action();
}
}
}
Xaml(注意TemplateColumn而不是CheckBoxColumn,因为this)。
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="clr-namespace:WpfApplication1.ViewModels"
Title="MainWindow" Height="350" Width="500">
<Window.DataContext>
<vm:CustomersViewModel />
</Window.DataContext>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<DockPanel Grid.Row="0">
<Button Content="Previous" Command="{Binding MovePreviousCommand}" Margin="2"/>
<Button Content="Next" Command="{Binding MoveNextCommand}" Margin="2"/>
<TextBlock Grid.Row="0" Margin="2" VerticalAlignment="Center" HorizontalAlignment="Right" DockPanel.Dock="Right">
<TextBlock.Text>
<MultiBinding StringFormat="Page {0}/{1}">
<Binding Path="PageNumber" />
<Binding Path="TotalPages" />
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</DockPanel>
<DataGrid ItemsSource="{Binding CustomerCollection}" Grid.Row="1">
<DataGrid.Columns>
<DataGridTemplateColumn Header="Active">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<CheckBox IsChecked="{Binding Path=IsActive, UpdateSourceTrigger=PropertyChanged}" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTextColumn Header="First Name" Width="*" Binding="{Binding FirstName}"/>
<DataGridTextColumn Header="Last Name" Width="*" Binding="{Binding LastName}"/>
</DataGrid.Columns>
</DataGrid>
</Grid>
</Window>
版本管理似乎存在轻微问题(不会阻止代码工作),因此您可能想要评论PagedCollectionView.MoveNext
中的前四行。
public bool MoveNext()
{
//if (this._timestamp != this._collectionView.Timestamp)
//{
// throw new InvalidOperationException(PagedCollectionViewResources.EnumeratorVersionChanged);
//}
switch (this._position)