我在更新DataGrid分组标题时遇到问题。当我添加或删除一条记录时，除非我重新选择总记录，否则总不会更新，有时甚至编辑记录也不会更新总记录。我根据我运气不好阅读的一些论坛帖子的建议添加了INotifyPropertyChanged，IEditableObject和IsLiveGroupingRequested。我在转换器函数上设置了一个断点，并且我注意到当我添加/删除/编辑记录时它不会触发，直到对表进行排序时才触发。我不确定我在做什么错。
xaml
<Window x:Class="WpfApp2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApp2"
mc:Ignorable="d"
xmlns:s="clr-namespace:System.ComponentModel;assembly=WindowsBase"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<local:Converter1 x:Key="c1"/>
<CollectionViewSource x:Key="cvs1" Source="{Binding Path=Lines, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}">
<CollectionViewSource.GroupDescriptions>
<PropertyGroupDescription PropertyName="Type"/>
</CollectionViewSource.GroupDescriptions>
</CollectionViewSource>
</Window.Resources>
<DataGrid Name="_dataGrid1" ItemsSource="{Binding Source={StaticResource cvs1}}">
<DataGrid.GroupStyle>
<GroupStyle>
<GroupStyle.ContainerStyle>
<Style TargetType="GroupItem">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="GroupItem">
<StackPanel>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="0" Content="{Binding Path=Name}" Padding="0"/>
<Label Grid.Column="1" Content="{Binding Converter={StaticResource c1}}" Padding="0"/>
</Grid>
<ItemsPresenter/>
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</GroupStyle.ContainerStyle>
</GroupStyle>
</DataGrid.GroupStyle>
</DataGrid>
</Window>
隐藏代码
using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Globalization;
using System.Linq;
using System.Windows;
using System.Windows.Data;
namespace WpfApp2
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
Transaction transaction = new Transaction();
transaction.Lines.Add(new TransactionLine() { Account = "ACCOUNT1", Type = "ACCOUNT", Amount = -41.86 });
transaction.Lines.Add(new TransactionLine() { Account = "BUDGET1", Type = "BUDGET", Amount = 41.86 });
transaction.Lines.Add(new TransactionLine() { Account = "CATEGORY1", Type = "CATEGORY", Amount = 41.86 });
this.DataContext = transaction;
}
}
public class Transaction
{
public Transaction()
{
this.Lines = new ObservableCollection<TransactionLine>();
}
public DateTime Date { get; set; }
public string Payee { get; set; }
public ObservableCollection<TransactionLine> Lines { get; set; }
}
public class TransactionLine : INotifyPropertyChanged, IEditableObject
{
void IEditableObject.BeginEdit()
{
}
void IEditableObject.CancelEdit()
{
}
void IEditableObject.EndEdit()
{
}
public TransactionLine() { }
private string _account;
private string _type;
private double _amount;
public string Account
{
get
{
return this._account;
}
set
{
this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("Account"));
this._account = value;
}
}
public string Type
{
get
{
return this._type;
}
set
{
this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("Type"));
this._type = value;
}
}
public double Amount
{
get
{
return this._amount;
}
set
{
this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("Amount"));
this._amount = value;
}
}
public event PropertyChangedEventHandler PropertyChanged;
}
public class Converter1 : IValueConverter
{
object IValueConverter.Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return Math.Round(((CollectionViewGroup)value).Items.Sum(l => ((TransactionLine)l).Amount), 2);
}
object IValueConverter.ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
}
答案 0 :(得分：1)
在将新值分配给后备字段之前，您要调用PropertyChanged事件。将var EXTRACTED_NAME = Server.MapPath("~/upload/shp/example/");
string shapeFilePath = @"\example.shp";
shapeFilePath = EXTRACTED_NAME + shapeFilePath;
Shapefile indexMapFile = Shapefile.OpenFile(shapeFilePath);
indexMapFile.Reproject(KnownCoordinateSystems.Geographic.World.WGS1984);
分配给字段后，请确保要调用它。
override fun onBackPressed() {
if (tabLayout.selectedTabPosition != 0) {
tabLayout.getTabAt(0)?.select()
} else {
super.onBackPressed()
}
}
答案 1 :(得分：1)
这里的问题是仅在设置了databound属性时才调用转换器。而且，由于您绑定到CollectionViewGroup本身，所以在向Convert添加新项目时将不会调用ObservableCollection<TransactionLine>方法。
您不仅可以绑定到CollectionViewGroup本身，还可以使用MultiBinding和IMultiValueConverter实现来绑定到源集合的Count属性：< / p>
public class Converter1 : IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
return Math.Round(((CollectionViewGroup)values[0]).Items.Sum(l => ((TransactionLine)l).Amount), 2);
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
XAML：
<ControlTemplate TargetType="GroupItem">
<StackPanel>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="0" Content="{Binding Path=Name}" Padding="0"/>
<Label Grid.Column="1" Padding="0">
<Label.Content>
<MultiBinding Converter="{StaticResource c1}">
<Binding Path="." />
<Binding Path="Items.Count" />
</MultiBinding>
</Label.Content>
</Label>
</Grid>
<ItemsPresenter/>
</StackPanel>
</ControlTemplate>
答案 2 :(得分：0)
我在这个问题上花了很长时间，发现以下更新组信息（例如组标题）的简便方法是：
Dispatcher.Invoke(() =>
{
DataInfosGrid.Items.Refresh();
});
您也可以更改DataGrid ItemsSource，但我认为它对您的应用程序来说很重！
再见！ ;-D
奥利维尔。