将实体绑定到具有EF 7（核心）的WPF数据网格中 [英] Binding entity into WPF datagrid with EF 7 (core)

问题描述

我有一个简单的数据绑定问题。我不能得到datagrid DeviceDataGrid 可视化实体信息。 MainWindow.xaml 文件如下：

 < Window 
 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/2008xmlns：mc =http://schemas.openxmlformats.org/markup-compatibility/2006xmlns：domain = clr-namespace：FxEditorDatabaseStructure.Core.Domain
 mc：Ignorable =dx：Class =FxEditorDatabaseStructure.MainWindow
 Title =MainWindowHeight =350Width =525 =Window_Loaded> 
< Window.Resources> 
< CollectionViewSource x：Key =DeviceViewSourced：DesignSource ={d：DesignInstance {x：Type domain：Device}，CreateList = True}/> 
< /Window.Resources> 
< Grid DataContext ={StaticResource DeviceViewSource}> 
< DataGrid x：Name =DeviceDataGridAutoGenerateColumns =FalseEnableRowVirtualization =TrueItemsSource ={Binding}Margin =0,64,0,0RowDetailsVisibilityMode =VisibleWhenSelected> 
< DataGrid.Columns> 
< DataGridTextColumn x：Name =NameColumnBinding ={Binding Name}Header =NameWidth =250/> 
< DataGridTextColumn x：Name =SocketCountColumnBinding ={Binding DeviceId}Header =IdWidth =Auto/> 
< DataGridTextColumn x：Name =DescriptionColumnBinding ={Binding Description}Header =DescriptionWidth =Auto/> 
< DataGridTextColumn x：Name =ProductTypeColumnBinding ={Binding ProductType}Header =Product TypeWidth =*/> 
< /DataGrid.Columns> 
< / DataGrid> 
< Button Content =AddHorizo​​ntalAlignment =LeftMargin =23,25,0,0VerticalAlignment =TopWidth =75RenderTransformOrigin = -  0.143，-0.057Click = AddDevice_Click/> 
< / Grid> 
< / Window> 
  

并尝试在MainWindow上的实体中可视化数据。
正确创建数据库，甚至添加按钮也可以正常工作。我可以使用Firefox SQLite Manager查看。

这是一个xaml.cs文件，它将实体加载到数据网格后，将实体加载到内存中：

  public partial class MainWindow：Window 
 {
 private FxContext _context = new FxContext（）; 
 
 public MainWindow（）
 {
 InitializeComponent（）; 
 _context.Database.Migrate（）; 
} 
 private void Window_Loaded（object sender，RoutedEventArgs e）
 {
 _context.Devices.Add（new Device 
 {
 ProductCode =100 ，
 Name =LUX999，
描述=Measurement device，
 Supplier =X，
 Category =Sensors，
 ProductType =Field设备，
 TimeCreated = DateTime.Now 
}）; 
 _context.SaveChanges（）; 
 
 System.Windows.Data.CollectionViewSource deviceViewSource =（（System.Windows.Data.CollectionViewSource）（this.FindResource（DeviceViewSource）））; 
 _context.Devices.Load（）; 
 _context.Sockets.Load（）; 
 _context.ProductTypes.Load（）; 
 deviceViewSource.Source = _context.Devices.GetLocal（）; 
 deviceViewSource.Source = _context.Categories.GetLocal（）; 
 deviceViewSource.Source = _context.ProductTypes.GetLocal（）; 
} 
 
 protected override void OnClosing（System.ComponentModel.CancelEventArgs e）
 {
 base.OnClosing（e）; 
 
 _context.Dispose（）; 
} 
 
 private void AddDevice_Click（object sender，RoutedEventArgs e）
 {
 _context.Devices.Add（
 new Device 
 {
 TimeCreated = DateTime.Now，
 Name =New Device at+ DateTime.Now.ToShortDateString（）
}）; 
 
 _context.SaveChanges（）; 
} 
} 
} 
  

因为EF7（核心）仍然缺少local（）的实现我正在使用一个替代扩展方法。

  public static class Extensions 
 {
 public static ObservableCollection< TEntity> GetLocal< TEntity>（此DbSet< TEntity>集合）
其中TEntity：class 
 {
 var context = set.GetService< DbContext>（）; 
 var data = context.ChangeTracker.Entries< TEntity>（）。选择（e => e.Entity）; 
 var collection = new ObservableCollection< TEntity>（data）; 
 
 collection.CollectionChanged + =（s，e）=> 
 {
 if（e.NewItems！= null）
 {
 context.AddRange（e.NewItems.Cast< TEntity>（））; 
} 
 
 if（e.OldItems！= null）
 {
 context.RemoveRange（e.OldItems.Cast< TEntity>（））; 
} 
}; 
 
 return collection; 
} 
} 
  

当我运行应用程序时，datagrid不显示任何在数据库的列表视图中的值。不知怎的，这行不正确地转移实体的 deviceViewSource.Source = _context.Devices.GetLocal（）; 或一些绑定过程在xaml文件中是错误的

任何想法我做错了什么？

解决方案

问题是，您将 deviceViewSource.Source ，然后替换为Categories，然后使用ProductTypes

  deviceViewSource.Source = _context.Devices.GetLocal（）; 
 deviceViewSource.Source = _context.Categories.GetLocal（）; 
 deviceViewSource.Source = _context.ProductTypes.GetLocal（）; 
  

在，而您正在将数据绑定到ProductTypes ...删除两条底线。

我相信你不需要GetLocal（）方法。尝试这样：

  deviceViewSource.Source = _context.Devices 
  

I have a simple problem with data binding. I'm not able to get the datagrid DeviceDataGrid to visualise the entity information. The MainWindow.xaml file is as follows:

<Window 
        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:domain="clr-namespace:FxEditorDatabaseStructure.Core.Domain"
    mc:Ignorable="d" x:Class="FxEditorDatabaseStructure.MainWindow"
        Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded">
    <Window.Resources>
        <CollectionViewSource x:Key="DeviceViewSource" d:DesignSource="{d:DesignInstance {x:Type domain:Device}, CreateList=True}"/>
    </Window.Resources>
    <Grid DataContext="{StaticResource DeviceViewSource}">
        <DataGrid x:Name="DeviceDataGrid" AutoGenerateColumns="False" EnableRowVirtualization="True" ItemsSource="{Binding}" Margin="0,64,0,0" RowDetailsVisibilityMode="VisibleWhenSelected">
            <DataGrid.Columns>
                <DataGridTextColumn x:Name="NameColumn" Binding="{Binding Name}" Header="Name" Width="250"/>
                <DataGridTextColumn x:Name="SocketCountColumn" Binding="{Binding DeviceId}" Header="Id" Width="Auto"/>
                <DataGridTextColumn x:Name="DescriptionColumn" Binding="{Binding Description}" Header="Description" Width="Auto"/>
                <DataGridTextColumn x:Name="ProductTypeColumn" Binding="{Binding ProductType}" Header="Product Type" Width="*"/>
            </DataGrid.Columns>
        </DataGrid>
        <Button Content="Add" HorizontalAlignment="Left" Margin="23,25,0,0" VerticalAlignment="Top" Width="75" RenderTransformOrigin="-0.143,-0.057" Click="AddDevice_Click"/>
    </Grid>
</Window>

And trying to visualise the data within the entity on MainWindow. The database is correctly created and even the add button works. This I am able to see with Firefox SQLite Manager.

Here is the xaml.cs file which is "binding" the entity into the datagrid after eager loading entities into memory:

    public partial class MainWindow : Window
    {
        private FxContext _context = new FxContext();

        public MainWindow()
        {
            InitializeComponent();
            _context.Database.Migrate();
        }
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            _context.Devices.Add(new Device
            {
                ProductCode = "100",
                Name = "LUX999",
                Description = "Measurement device",
                Supplier = "X",
                Category = "Sensors",
                ProductType = "Field device",
                TimeCreated = DateTime.Now
            });
            _context.SaveChanges();

            System.Windows.Data.CollectionViewSource deviceViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("DeviceViewSource")));
            _context.Devices.Load();
            _context.Sockets.Load();
            _context.ProductTypes.Load();
            deviceViewSource.Source = _context.Devices.GetLocal();
            deviceViewSource.Source = _context.Categories.GetLocal();
            deviceViewSource.Source = _context.ProductTypes.GetLocal();
        }

        protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
        {
            base.OnClosing(e);

            _context.Dispose();
        }

        private void AddDevice_Click(object sender, RoutedEventArgs e)
        {
            _context.Devices.Add(
                new Device
                {
                    TimeCreated = DateTime.Now,
                    Name = "New Device at " + DateTime.Now.ToShortDateString()
                });

            _context.SaveChanges();
        }
    }
}

Because the EF7 (core) still lacks the implementation of local() I'm using an alternative extension method.

public static class Extensions
{
    public static ObservableCollection<TEntity> GetLocal<TEntity>(this DbSet<TEntity> set)
        where TEntity : class
    {
        var context = set.GetService<DbContext>();
        var data = context.ChangeTracker.Entries<TEntity>().Select(e => e.Entity);
        var collection = new ObservableCollection<TEntity>(data);

        collection.CollectionChanged += (s, e) =>
        {
            if (e.NewItems != null)
            {
                context.AddRange(e.NewItems.Cast<TEntity>());
            }

            if (e.OldItems != null)
            {
                context.RemoveRange(e.OldItems.Cast<TEntity>());
            }
        };

        return collection;
    }
}

When I run the application the datagrid is not showing any values from the database in its list view. Somehow this line is not transferring the entity correctly deviceViewSource.Source = _context.Devices.GetLocal(); OR some binding procedure is wrong in the xaml-file?

Any ideas what I'm doing wrong?

解决方案

The problem is, that you set deviceViewSource.Source to devices, then replaced with Categories, then with ProductTypes

deviceViewSource.Source = _context.Devices.GetLocal();
deviceViewSource.Source = _context.Categories.GetLocal();
deviceViewSource.Source = _context.ProductTypes.GetLocal();

at the and, you are databanding to ProductTypes... Remove the two bottom lines.

I believe that you dont need the GetLocal() method neither. Try this:

deviceViewSource.Source = _context.Devices

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