[英]DataGrid doesn't deselect hidden items properly when SelectionMode=“Extended”
WPF DataGrid
出現問題,這使我發瘋。 讓我們考慮一下這種視圖模型:
public class ViewModel : INotifyPropertyChanged
{
public int Id { get; set; }
public string Name { get; set; }
public bool IsSelected
{
get { return isSelected; }
set
{
System.Diagnostics.Debug.WriteLine("{0}'s IsSelected new value is: {1}", Name, value);
if (isSelected != value)
{
isSelected = value;
OnPropertyChanged("IsSelected");
}
}
}
private bool isSelected;
// INPC implementation
}
...此XAML:
<Window x:Class="WpfApplication5.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<DataGrid ItemsSource="{Binding}" IsReadOnly="True" AutoGenerateColumns="False"
SelectionMode="Extended" SelectionUnit="FullRow">
<DataGrid.ItemContainerStyle>
<Style TargetType="{x:Type DataGridRow}">
<Setter Property="IsSelected" Value="{Binding IsSelected}"/>
</Style>
</DataGrid.ItemContainerStyle>
<DataGrid.Columns>
<DataGridCheckBoxColumn Header="Is selected" Binding="{Binding IsSelected}"/>
<DataGridTextColumn Header="Id" Binding="{Binding Id}"/>
<DataGridTextColumn Header="Name" Width="*" Binding="{Binding Name}"/>
</DataGrid.Columns>
</DataGrid>
</Grid>
</Window>
...以及以下代碼:
public partial class MainWindow : Window
{
private IList<ViewModel> GenerateViewModels()
{
var viewModels = new List<ViewModel>();
for (var i = 0; i < 100; i++)
{
viewModels.Add(new ViewModel
{
Id = i,
Name = string.Format("Item {0}", i)
});
}
return viewModels;
}
public MainWindow()
{
InitializeComponent();
DataContext = GenerateViewModels();
}
}
情況1。
調試輸出:
Item 0's IsSelected new value is: True
Item 0's IsSelected new value is: False
Item 10's IsSelected new value is: True
Item 10's IsSelected new value is: False
情況2
調試輸出:
Item 0's IsSelected new value is: True
Item 1's IsSelected new value is: True
Item 2's IsSelected new value is: True
Item 2's IsSelected new value is: False
Item 10's IsSelected new value is: True
當擴展選擇模式時,問題正在重現。 當它是單個時,一切正常。
問題:
1.我想念什么嗎? 2.有人知道解決方法嗎?
更新 。
我為網格添加了SelectionChanged
事件處理程序:
private void MyGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e.AddedItems != null)
{
foreach (var item in e.AddedItems.Cast<ViewModel>())
{
System.Diagnostics.Debug.WriteLine("** Item {0} is added to selection.", item.Id);
}
}
if (e.RemovedItems != null)
{
foreach (var item in e.RemovedItems.Cast<ViewModel>())
{
System.Diagnostics.Debug.WriteLine("** Item {0} is removed from selection.", item.Id);
}
}
e.Handled = true;
}
調試輸出顯示, SelectedItems
集合已正確更新。 例如,對於第一種情況,輸出為:
Item 0's IsSelected new value is: True
** Item 0 is added to selection.
Item 0's IsSelected new value is: False
Item 10's IsSelected new value is: True
** Item 10 is added to selection.
** Item 0 is removed from selection.
Item 10's IsSelected new value is: False
** Item 0 is added to selection.
** Item 10 is removed from selection.
但是綁定數據屬性IsSelected
不會更新!
至少找到了一種解決方法,它與問題的更新有關。
讓我們對SelectionChanged
事件處理程序進行一些修改:
private void MyGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e.AddedItems != null)
{
foreach (var item in e.AddedItems.Cast<ViewModel>())
{
System.Diagnostics.Debug.WriteLine("** Item {0} is added to selection.", item.Id);
if (!item.IsSelected)
{
// if bound data item still isn't selected, fix this
item.IsSelected = true;
}
}
}
if (e.RemovedItems != null)
{
foreach (var item in e.RemovedItems.Cast<ViewModel>())
{
System.Diagnostics.Debug.WriteLine("** Item {0} is removed from selection.", item.Id);
if (item.IsSelected)
{
// if bound data item still is selected, fix this
item.IsSelected = false;
}
}
}
e.Handled = true;
}
但這絕對是DataGrid
的錯誤,不是嗎?
我嘗試了一下,我認為您需要同時將isSelected設置為false。 這個對我有用。 但是感謝您的最初解決方案! 這對我幫助很大。
private void MyGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e.AddedItems != null)
{
foreach (var item in e.AddedItems.Cast<ViewModel>())
{
System.Diagnostics.Debug.WriteLine("** Item {0} is added to selection.", item.Id);
if (!item.IsSelected)
{
// if bound data item still isn't selected, fix this
item.IsSelected = false;
}
}
}
if (e.RemovedItems != null)
{
foreach (var item in e.RemovedItems.Cast<ViewModel>())
{
System.Diagnostics.Debug.WriteLine("** Item {0} is removed from selection.", item.Id);
if (item.IsSelected)
{
// if bound data item still is selected, fix this
item.IsSelected = false;
}
}
}
e.Handled = true;
}
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