我有一个使用Virtualization的DataGrid,其中一列使用DataGridTemplateColumn和ComboBox。但是,当我在DataGrid中向左/向右滚动(将ComboBox列移出视图然后进入视图)时,ComboBox将丢失其选择。
设置EnableColumnVirtualization =“False”确实解决了问题,但后来我显然失去了列的虚拟化。
是否存在不涉及禁用虚拟化的解决方案?
我已经整理了一个简单的解决方案来证明这个问题。如果你运行它并且从左向右滚动非常快,你会看到ComboBox最终变空并且在它周围显示一个红色边框。
XAML:
<Window x:Class="SimpleReproTest.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" Loaded="Window_Loaded">
<Grid>
<DataGrid x:Name="MyGrid" AutoGenerateColumns="False" EnableColumnVirtualization="True" EnableRowVirtualization="True"
VirtualizingStackPanel.VirtualizationMode="Standard" VirtualizingStackPanel.IsVirtualizing="True">
<DataGrid.Columns>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTemplateColumn>
<DataGridTemplateColumn.HeaderTemplate>
<DataTemplate>
<TextBlock Text="ComboBox Column"/>
</DataTemplate>
</DataGridTemplateColumn.HeaderTemplate>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding DummyItems}"
SelectedValue="{Binding DummySelection}"
SelectedValuePath="Key"
DisplayMemberPath="Value"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
<DataGridTextColumn Header="DummyColumn" Binding="{Binding Dummy}"></DataGridTextColumn>
</DataGrid.Columns>
</DataGrid>
</Grid>
代码背后:
using System.Collections.Generic;
using System.Windows;
using System.Collections.ObjectModel;
namespace SimpleReproTest
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
ObservableCollection<DummyColumn> MyData;
public MainWindow()
{
InitializeComponent();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
MyData = new ObservableCollection<DummyColumn>();
for (int i = 0; i < 50; i++)
MyData.Add(new DummyColumn());
MyGrid.ItemsSource = MyData;
}
}
public class DummyColumn
{
public ObservableCollection<KeyValuePair<int, string>> DummyItems {get; set;}
public string Dummy { get; set; }
public int DummySelection { get; set; }
public DummyColumn()
{
Dummy = "...";
DummySelection = 0;
DummyItems = new ObservableCollection<KeyValuePair<int,string>>();
DummyItems.Add(new KeyValuePair<int,string>(0, "Item 0"));
DummyItems.Add(new KeyValuePair<int,string>(1, "Item 1"));
}
}
}
答案 0 :(得分:1)
我的答案的关键是你只需要将组合的Text属性与UpdateSourceTrigger等于属性更改绑定。
这是唯一正确的解决方案。 不要被其他不相关的细节搞糊涂。如果你非常了解WPF(很遗憾,很少有人这么做)你必须要知道,当UI属性的更改源于UI对象本身时,OnPropertyChanged(或等效的通知程序)绝对无用。
尝试使用此xaml
<DataTemplate>
<ComboBox ItemsSource="{Binding DummyItems}"
SelectedValue="{Binding DummySelection}"
SelectedValuePath="Key"
Text="{Binding DummySel, UpdateSourceTrigger=PropertyChanged}"
DisplayMemberPath="Value"/>
</DataTemplate>
和ViewModel
private string dummySel;
public string DummySel
{
get { return dummySel; }
set { dummySel = value;
//OnPropertyChanged(() => DummySel);
}
}
private int dummySelection;
public int DummySelection {
get { return dummySelection; }
set {
dummySelection = value;
//OnPropertyChanged(()=>DummySelection);
}
}