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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 =AddHorizontalAlignment =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。
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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