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我有實體WPF樹視圖，從數據庫表默認建立其引用本身自referensed實體使用綁定轉換器和的ObservableCollection
我是新來的，低信譽不alows我添加圖像，所以我會盡我所能寫。
地區：EntityObject
屬性：
ID
ParentArea_ID
導航屬性：
區 - 一個區域，區域的集合
ParentArea - 以區instanse
我想用數據庫表中的數據填充樹視圖。我發現了2個選項：使用來自here的包裝或綁定轉換器。我是初學者，可能是錯誤的，但它使用綁定轉換器與我聯繫是更好的方法。
我發現我必須做與地區收集了一類新作導航easyer執行，添加，刪除
class AreasCollection:ObservableCollection<Area>
{
private DBEntities _context;
public DBEntities Context
{
get { return _context; }
}
public AreasCollection(IEnumerable<Area> Areas, DBEntities context)
: base(Areas)
{
_context = context;
foreach (Area a in Areas)
{
a.Areas.AssociationChanged +=new CollectionChangeEventHandler(Areas_AssociationChanged);
}
}
void Areas_AssociationChanged(object sender, CollectionChangeEventArgs e)
{
if (e.Action == CollectionChangeAction.Remove)
{
this.Context.DeleteObject((Area)e.Element);
this.Context.DeleteObject((SpareDevice)e.Element);
this.Context.DeleteObject((AreaDevice)e.Element);
this.Context.DeleteObject((Executor)e.Element);
}
}
protected override void InsertItem(int index, Area item)
{
item.Areas.AssociationChanged += new CollectionChangeEventHandler(Areas_AssociationChanged);
this.Context.AddToAreas(item);
base.InsertItem(index, item);
}
protected override void RemoveItem(int index)
{
Area a = this[index];
a.Areas.AssociationChanged -= Areas_AssociationChanged;
for (int i = a.Areas.Count - 1; i >= 0; i--)
{
this.Context.DeleteObject(a.Areas.ElementAt(i));
}
for (int i = a.SpareDevices.Count - 1; i >= 0; i--)
{
this.Context.DeleteObject(a.SpareDevices.ElementAt(i));
}
for (int i = a.AreaDevices.Count - 1; i >= 0; i--)
{
this.Context.DeleteObject(a.AreaDevices.ElementAt(i));
}
for (int i = a.Executors.Count - 1; i >= 0; i--)
{
this.Context.DeleteObject(a.Executors.ElementAt(i));
}
this.Context.DeleteObject(this[index]);
base.RemoveItem(index);
}
}
而且我發現我必須做一個新的轉換器類
public class AreasConverter : IValueConverter
{
public object Convert(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
var item = value as Area;
return item.Areas.Where(a => a.ParentArea_ID == item.ID);
}
public object ConvertBack(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
我的XAML：
<TreeView Name="AreasTreeView" Height="350" ItemsSource="{Binding Converter={StaticResource AreasConverter}}" ItemTemplate="{StaticResource ItemTemplate}">
<TreeView.Resources>
<local:AreasConverter x:Key="AreasConverter"/>
<HierarchicalDataTemplate x:Key="ItemTemplate" ItemsSource="{Binding Converter={StaticResource AreasConverter}}">
<TextBlock Text="{Binding Path=ShortName}" />
</HierarchicalDataTemplate>
</TreeView.Resources>
</TreeView>
而且XAML.cs
public partial class MainWindow : Window
{
private DBEntities context = new DBEntities();
private CollectionViewSource AreasConverterViewSourse;
private ListCollectionView AreasConverter;
public MainWindow()
{
InitializeComponent();
AreasTreeView.ItemsSource = context.Areas.Where(a => a.ParentArea_ID == null);
AreasConverterViewSourse = (CollectionViewSource)FindResource("AreasConverter");
this.AreasConverter = (ListCollectionView)this.AreasConverterViewSourse.View;
}
}
因爲它是我有一個錯誤資源「ItemTemplate」無法解析。
如果我刪除的ItemTemplate = 「{StaticResource的ItemTemplate中}」
從
<TreeView Name="AreasTreeView" Height="350" ItemsSource="{Binding Converter={StaticResource AreasConverter}}" ItemTemplate="{StaticResource ItemTemplate}">
錯誤消失，但是當我嘗試運行應用程序exeption發生
System.Windows.Markup.XamlParseException occurred
HResult=-2146233087
Message='Provide value on 'System.Windows.StaticResourceExtension' threw an exception.' Line number '30' and line position '61'.
Source=PresentationFramework
LineNumber=30
LinePosition=61
StackTrace:
at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
at System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
at Maintenance.MainWindow.InitializeComponent() in c:\DATA\Maintenance\Maintenance\MainWindow.xaml:line 1
at Maintenance.MainWindow..ctor() in c:\DATA\Maintenance\Maintenance\MainWindow.xaml.cs:line 44
InnerException:
HResult=-2146233088
Message=Cannot find resource named 'AreasConverter'. Resource names are case sensitive.
Source=PresentationFramework
StackTrace:
at System.Windows.StaticResourceExtension.ProvideValue(IServiceProvider serviceProvider)
at MS.Internal.Xaml.Runtime.ClrObjectRuntime.CallProvideValue(MarkupExtension me, IServiceProvider serviceProvider)
InnerException:
這是我的第一個wpf應用程序和第一個數據庫設計（16個表格）。從這個項目開始，我已經花了6個弱點開始使用sql server和wpf視頻，Google時間和日期。我的大腦開始沸騰。如果答案儘可能詳細，我會表示贊同。
感謝您的幫助！