c# – wpf DataGrid – 已添加具有相同键的项

C# 前端之家
前端之家收集整理的这篇文章主要介绍了c# – wpf DataGrid – 已添加具有相同键的项，前端之家小编觉得挺不错的，现在分享给大家，也给大家做个参考。
我看到很多与此问题相关的帖子,但我找不到解决方案

我有下一个WPF DataGrid：

  1. <DataGrid Grid.Column="1"
  2.           Grid.Row="4"
  3.           AutoGenerateColumns="False"
  4.           ItemsSource="{Binding MapsGrid}"
  5.           SelectedItem="{Binding DataContext.CategoriesSelectedRow,RelativeSource={RelativeSource AncestorType={x:Type UserControl}},Mode=OneWayToSource}"
  6.           SelectionMode="Single"
  7.           CanUserReorderColumns="False"
  8.           CanUserResizeColumns="False"
  9.           CanUserDeleteRows="False"
  10.           CanUserResizeRows="False"
  11.           CanUserAddRows="False">
  12.   <DataGrid.Columns>
  13.     <DataGridTemplateColumn Header="Main Category"
  14.                             Width="*">
  15.       <DataGridTemplateColumn.HeaderStyle>
  16.         <Style TargetType="DataGridColumnHeader">
  17.           <Setter Property="HorizontalContentAlignment"
  18.                   Value="Center" />
  19.           <Setter Property="FontSize"
  20.                   Value="16" />
  21.         </Style>
  22.       </DataGridTemplateColumn.HeaderStyle>
  23.       <DataGridTemplateColumn.CellTemplate>
  24.         <DataTemplate>
  25.           <ComboBox ItemsSource="{Binding MainCategoriesColl}"
  26.                     DisplayMemberPath="Category"
  27.                     SelectedItem="{Binding MainCategorySelectedItem,UpdateSourceTrigger=LostFocus,Mode=OneWayToSource}" />
  28.         </DataTemplate>
  29.       </DataGridTemplateColumn.CellTemplate>
  30.     </DataGridTemplateColumn>
  31.  
  32.     <DataGridTemplateColumn Header="Sub Category"
  33.                             Width="*">
  34.       <DataGridTemplateColumn.HeaderStyle>
  35.         <Style TargetType="DataGridColumnHeader">
  36.           <Setter Property="HorizontalContentAlignment"
  37.                   Value="Center" />
  38.           <Setter Property="FontSize"
  39.                   Value="16" />
  40.         </Style>
  41.       </DataGridTemplateColumn.HeaderStyle>
  42.       <DataGridTemplateColumn.CellTemplate>
  43.         <DataTemplate>
  44.           <ComboBox ItemsSource="{Binding SubCategoriesColl}"
  45.                     DisplayMemberPath="Category"
  46.                     SelectedItem="{Binding SubCategorySelectedItem,Mode=TwoWay}" />
  47.         </DataTemplate>
  48.       </DataGridTemplateColumn.CellTemplate>
  49.     </DataGridTemplateColumn>
  50.   </DataGrid.Columns>
  51. </DataGrid>

这个DataGrid包含2个ComboBoxes. ItemSource对象是下一个：

  1. public class MapsDescModel : NotificationObject,IEqualityComparer<MapsDescModel>,IEquatable<MapsDescModel>
  2. {
  3.     public MapsDescModel(ObservableCollection<MainCategories> mainCategoty)
  4.     {
  5.         MainCategoriesColl = mainCategoty;
  6.  
  7.     }
  8.  
  9.     public static event Action OnSelectionHandler;
  10.  
  11.     private static void OnSelection()
  12.     {
  13.         if (OnSelectionHandler != null)
  14.         {
  15.             OnSelectionHandler();
  16.         }
  17.     }
  18.  
  19.     private MainCategories _mainCategorySelectedItem;
  20.     public MainCategories MainCategorySelectedItem
  21.     {
  22.         get { return _mainCategorySelectedItem; }
  23.         set
  24.         {
  25.             if (Equals(value,_mainCategorySelectedItem)) return;
  26.             _mainCategorySelectedItem = value;
  27.             RaisePropertyChanged("MainCategorySelectedItem");
  28.             RaisePropertyChanged("SubCategoriesColl");
  29.         }
  30.     }
  31.  
  32.     private SubCategories _subCategorySelectedItem;
  33.     public SubCategories SubCategorySelectedItem
  34.     {
  35.         get { return _subCategorySelectedItem; }
  36.         set
  37.         {
  38.             if (Equals(value,_subCategorySelectedItem)) return;
  39.             _subCategorySelectedItem = value;
  40.             RaisePropertyChanged("SubCategorySelectedItem");
  41.             OnSelection();
  42.  
  43.         }
  44.     }
  45.  
  46.  
  47.     private ObservableCollection<MainCategories> _mainCategoriesColl;
  48.     public ObservableCollection<MainCategories> MainCategoriesColl
  49.     {
  50.         get { return _mainCategoriesColl; }
  51.         set
  52.         {
  53.             if (Equals(value,_mainCategoriesColl)) return;
  54.             _mainCategoriesColl = value;
  55.             RaisePropertyChanged("MainCategoriesColl");
  56.         }
  57.     }
  58.  
  59.  
  60.     //Allow user see N/A category just if is the only subCategory that exists
  61.     public ObservableCollection<SubCategories> SubCategoriesColl
  62.     {
  63.         get
  64.         {
  65.             if (MainCategorySelectedItem != null && MainCategorySelectedItem.SubCategory.Any())
  66.                 if (MainCategorySelectedItem.SubCategory.Count() > 1)
  67.                 {
  68.                     return Infrastructure.Helpers.ExtensionMethods.ToObservableCollection(
  69.                         MainCategorySelectedItem.SubCategory.AsEnumerable().Where(p => p.Category != Infrastructure.Constants.Constants.NoSubCategory));
  70.                 }
  71.                 else return Infrastructure.Helpers.ExtensionMethods.ToObservableCollection(
  72.                         MainCategorySelectedItem.SubCategory.AsEnumerable());
  73.             else return new ObservableCollection<SubCategories>();
  74.         }
  75.     }
  76.  
  77.  
  78.     public bool Equals(MapsDescModel x,MapsDescModel y)
  79.     {
  80.         try
  81.         {
  82.             if (x.MainCategorySelectedItem == null && y.MainCategorySelectedItem == null)
  83.                 return true;
  84.             else if (x.MainCategorySelectedItem == null && y.MainCategorySelectedItem != null ||
  85.                 x.MainCategorySelectedItem != null && y.MainCategorySelectedItem == null)
  86.                 return false;
  87.             return
  88.                 x.MainCategorySelectedItem.MainCatID == y.MainCategorySelectedItem.MainCatID &&
  89.                 x.SubCategorySelectedItem.SubCatID == y.SubCategorySelectedItem.SubCatID;
  90.         }
  91.         catch (Exception ex)
  92.         {
  93.             ServiceLocator.Current.GetInstance<Infrastructure.SharedServices.IEnterpriseLibraryLogger>().Log(ex.Message,Category.Exception,Priority.High);
  94.             return false;
  95.         }
  96.     }
  97.  
  98.     public int GetHashCode(MapsDescModel obj)
  99.     {
  100.             if (Object.ReferenceEquals(obj,null)) return 0;
  101.  
  102.             if (obj.MainCategorySelectedItem == null || obj.SubCategorySelectedItem == null)
  103.                 return 0;
  104.             else return obj.SubCategorySelectedItem.Category.GetHashCode() + obj.MainCategorySelectedItem.GetHashCode();
  105.     }
  106.  
  107.     public bool Equals(MapsDescModel other)
  108.     {
  109.         return
  110.         this.Equals(this,other);  // use definition from IEqualityComparer<T>
  111.     }
  112.  
  113.     public override bool Equals(object obj)
  114.     {
  115.         MapsDescModel other = obj as MapsDescModel;
  116.         if (other == null)
  117.             return base.Equals(obj);
  118.         else
  119.             return this.Equals(other);
  120.     }
  121.  
  122.     public override int GetHashCode()
  123.     {
  124.         MapsDescModel other = this as MapsDescModel;
  125.         if (other == null)
  126.             return base.GetHashCode();
  127.         else
  128.             return this.GetHashCode(other);
  129.     }
  130. }

一切都很好,除了一个恼人的问题.
当我添加2行时,如果我在附加图片中的标记区域上单击几次,则会出现以下错误：

  1. System.ArgumentException was unhandled
  2.   HResult=-2147024809
  3.   Message=An item with the same key has already been added.
  4.   Source=mscorlib
  5.   StackTrace:
  6.        at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
  7.        at System.Collections.Generic.Dictionary`2.Insert(TKey key,TValue value,Boolean add)
  8.        at System.Collections.Generic.Dictionary`2..ctor(IDictionary`2 dictionary,IEqualityComparer`1 comparer)
  9.        at System.Windows.Controls.Primitives.Selector.InternalSelectedItemsStorage..ctor(InternalSelectedItemsStorage collection,IEqualityComparer`1 equalityComparer)
  10.        at System.Windows.Controls.Primitives.Selector.SelectionChanger.ApplyCanSelectMultiple()
  11.        at System.Windows.Controls.Primitives.Selector.SelectionChanger.End()
  12.        at System.Windows.Controls.SelectedItemCollection.EndUpdateSelectedItems()
  13.        at System.Windows.Controls.Primitives.MultiSelector.EndUpdateSelectedItems()
  14.        at System.Windows.Controls.DataGrid.MakeFullRowSelection(ItemInfo info,Boolean allowsExtendSelect,Boolean allowsMinimalSelect)
  15.        at System.Windows.Controls.DataGrid.HandleSelectionForRowHeaderAndDetailsInput(DataGridRow row,Boolean startDragging)
  16.        at System.Windows.Controls.Primitives.DataGridRowHeader.OnClick()
  17.        at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonDown(MouseButtonEventArgs e)
  18.        at System.Windows.UIElement.OnMouseLeftButtonDownThunk(Object sender,MouseButtonEventArgs e)
  19.        at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler,Object genericTarget)
  20.        at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler,Object target)
  21.        at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target,RoutedEventArgs routedEventArgs)
  22.        at System.Windows.EventRoute.InvokeHandlersImpl(Object source,RoutedEventArgs args,Boolean reRaised)
  23.        at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender,RoutedEvent newEvent)
  24.        at System.Windows.UIElement.OnMouseDownThunk(Object sender,Boolean reRaised)
  25.        at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender,RoutedEventArgs args)
  26.        at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
  27.        at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args,Boolean trusted)
  28.        at System.Windows.Input.InputManager.ProcessStagingArea()
  29.        at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
  30.        at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
  31.        at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd,InputMode mode,Int32 timestamp,RawMouseActions actions,Int32 x,Int32 y,Int32 wheel)
  32.        at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd,WindowMessage msg,IntPtr wParam,IntPtr lParam,Boolean& handled)
  33.        at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd,Int32 msg,Boolean& handled)
  34.        at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd,Boolean& handled)
  35.        at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
  36.        at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback,Object args,Int32 numArgs)
  37.        at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source,Delegate method,Int32 numArgs,Delegate catchHandler)
  38.        at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority,TimeSpan timeout,Int32 numArgs)
  39.        at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd,IntPtr lParam)
  40.        at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
  41.        at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
  42.        at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
  43.        at System.Windows.Threading.Dispatcher.Run()
  44.        at System.Windows.Application.RunDispatcher(Object ignore)
  45.        at System.Windows.Application.RunInternal(Window window)
  46.        at System.Windows.Application.Run(Window window)
  47.        at System.Windows.Application.Run()
  48.        at Malaria.App.Main() in c:\My Projects\Hebrew University\Malaria Management Console\Malaria\obj\Debug\App.g.cs:line 0
  49.        at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly,String[] args)
  50.        at System.AppDomain.ExecuteAssembly(String assemblyFile,Evidence assemblySecurity,String[] args)
  51.        at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
  52.        at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
  53.        at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext,ContextCallback callback,Object state,Boolean preserveSyncCtx)
  54.        at System.Threading.ExecutionContext.Run(ExecutionContext executionContext,Object state)
  55.        at System.Threading.ThreadHelper.ThreadStart()
  56.   InnerException:

我认为它可能与我的GetHashCode方法有关,但我不确定.
我找到了这个链接
http://leavinsprogramming.blogspot.co.il/2012/08/wpf-datagrid-and-random.html
它描述了我的问题,但那里没有解决方案.
有谁知道为什么会发生这种异常？

解决方法

引用 MSDN’s entry on Object.GetHashCode()：

In general,for mutable reference types,you should override GetHashCode only if:

  • You can compute the hash code from fields that are not mutable; or

  • You can ensure that the hash code of a mutable object does not change while the object is contained in a collection that relies on its hash code.

您当前的GetHashCode()实现调用GetHashCode(MapsDescModel obj),该方法依赖于可在集合中更改的可变字段.

更改GetHashCode()实现以返回不依赖于可更改字段的值.

猜你在找的C#相关文章

C#使用SharpZipLib创建压缩文件，并指定压缩文件夹路径（解决SharpZipLib压缩长路径显示问题）
在项目中使用SharpZipLib压缩文件夹的时候，遇到如果目录较深，则压缩包中的文件夹同样比较...
C#使用Parallel处理数据同步写入Datatable并使用BulkInsert批量导入数据库
项目需要，几十万张照片需要计算出每个照片的特征值（调用C++编写的DLL）。 业务流...
C# byte和10进制、16进制相互转换
var array = new byte[4]; var i = Encoding.UTF8.GetBytes(100.ToString(&quot;x2&am...
Winform下的Combox根据值来选中项
其实很简单，因为Combox的Item是一个K/V的object，那么就可以把它的items转换成IEnumerabl...
HM NIS Edit制作安装包时检测是否有.net4.6环境，没有的时候自动安装。
把.net4.6安装包打包进安装程序。 关键脚本如下： 头部引用字符串对比库 !include &qu...
WPF下使用FreeRedis操作RedisStream实现简单的消息队列
Redis Stream简介 Redis Stream是随着5.0版本发布的一种新的Redis数据类型： 高效消费者组...
C#进行图片压缩（对jpg压缩效果最好）
直接上代码 1 public static class ImageCompress 2 { 3 /// &lt;summary&gt; 4 /...
CefSharp访问需要认证网页或接口(在Request的Headers中添加认证Token)
然后在使用的时候，就可以获取到Header的内容了。
C#使用FileSystemWatcher来监控指定文件夹，并使用TCP/IP协议通过Socket发送到另外指定文件夹
项目需求： 局域网内有两台电脑，电脑A(Windows系统)主要是负责接收一些文件（远程桌面粘贴...
绿色版Mysql自动建立my.ini和命令行启动并动态指定datadir路径
1、先去下载绿色版的Mysql(https://cdn.mysql.com//archives/mysql-5.7/mysql-5.7.20-winx...
PHPJavaJava SEPythonC#C&C++RubyVBasp.NetGoPerlnettyDjangoDelphiJsp.NET CoreSpringFlaskSpringbootSpringMVCLuaLaravelMybatisAspGroovyThinkPHPYiiswoole
文件时间pythonm相等性PHP Warning时间问题问题解决pcntl_signal采样点wav模块动态文本调用频率限制对外暴露多个访问请求更新数据表模型结构type()方法比较速度手写体sobel算子保存模型Image类nn.Conv2dpytorch1.0kaggleDCGAN交并比range()用法打印模型反卷积卷积