在 VS 2015 和 VS 2013 上运行同一段代码的问题

Question

在 Visual Studio 2013 和 2015 中运行一段代码时，我得到两种不同的结果。在 Visual Studio 2015 上，我得到了一个 NullReference，在 2013 年它按应有的方式工作。此外，Visual Studio 2015 在 Windows 8.1 上的 Windows 10 和 2013 上运行。这段代码是：

private static T FindParentOfType<T>(DependencyObject o)
{
    dynamic parent = VisualTreeHelper.GetParent(o);
    return parent.GetType().IsAssignableFrom(typeof(T)) ? parent : FindParentOfType<T>(parent);
}

代码是这样调用的：

Grid RiskGrid = FindParentOfType<Grid>(ChampViewModelSel);

错误是Nullreference，当检查IsAssginableFrom，因为在VS2015找到一个帆布代替了在VS2013中找到的希望电网？

堆栈跟踪

  StackTrace  "   at Microsoft.CSharp.RuntimeBinder.SymbolTable.GetOriginalTypeParameterType(Type t)\r\n   
    at Microsoft.CSharp.RuntimeBinder.SymbolTable.AreTypeParametersEquivalent(Type t1, Type t2)\r\n   
    at Microsoft.CSharp.RuntimeBinder.SymbolTable.LoadMethodTypeParameter(MethodSymbol parent, Type t)\r\n   
    at Microsoft.CSharp.RuntimeBinder.SymbolTable.LoadSymbolsFromType(Type originalType)\r\n   
    at Microsoft.CSharp.RuntimeBinder.SymbolTable.AddMethodToSymbolTable(MemberInfo member, AggregateSymbol callingAggregate, MethodKindEnum kind)\r\n   
    at Microsoft.CSharp.RuntimeBinder.SymbolTable.AddNamesInInheritanceHierarchy(String name, BindingFlags flags, List 1 inheritance)\r\n   
    at Microsoft.CSharp.RuntimeBinder.SymbolTable.PopulateSymbolTableWithName(String name, IEnumerable 1 typeArguments, Type callingType)\r\n   
    at Microsoft.CSharp.RuntimeBinder.RuntimeBinder.PopulateSymbolTableWithPayloadInformation(DynamicMetaObjectBinder payload, Type callingType, ArgumentObject[] arguments)\r\n  
    at Microsoft.CSharp.RuntimeBinder.RuntimeBinder.BindCore(DynamicMetaObjectBinder payload, IEnumerable 1 parameters, DynamicMetaObject[] args, DynamicMetaObject& deferredBinding)\r\n
    at Microsoft.CSharp.RuntimeBinder.RuntimeBinder.Bind(DynamicMetaObjectBinder payload, IEnumerable 1 parameters, DynamicMetaObject[] args, DynamicMetaObject& deferredBinding)\r\n 
    at Microsoft.CSharp.RuntimeBinder.BinderHelper.Bind(DynamicMetaObjectBinder action, RuntimeBinder binder, IEnumerable 1 args, IEnumerable 1 arginfos, DynamicMetaObject onBindingError)\r\n 
    at Microsoft.CSharp.RuntimeBinder.CSharpInvokeMemberBinder.FallbackInvokeMember(DynamicMetaObject target, DynamicMetaObject[] args, DynamicMetaObject errorSuggestion)\r\n
    at System.Dynamic.DynamicMetaObject.BindInvokeMember(InvokeMemberBinder binder, DynamicMetaObject[] args)\r\n 
    at System.Dynamic.InvokeMemberBinder.Bind(DynamicMetaObject target, DynamicMetaObject[] args)\r\n
    at System.Dynamic.DynamicMetaObjectBinder.Bind(Object[] args, ReadOnlyCollection 1 parameters, LabelTarget returnLabel)\r\n
    at System.Runtime.CompilerServices.CallSiteBinder.BindCore[T](CallSite 1 site, Object[] args)\r\n 
    at System.Dynamic.UpdateDelegates.UpdateAndExecute2[T0,T1,TRet](CallSite site, T0 arg0, T1 arg1)\r\n
    at BC_Game.ViewModel.ChampionViewModel.FindParentOfType[T](DependencyObject o)\r\n 
    at BC_Game.ViewModel.ChampionViewModel.ManStart(ManipulationStartedEventArgs e)"    string

更新

在Win10上安装VS2013，问题依旧。VS2013 在 Win8.1 上运行良好

更新

从 Visual Studio 2013 wp 8.1

C:\Program Files (x86)\MSBuild\12.0\bin\Csc.exe /noconfig /nowarn:1701,1702,2008 /nostdlib+ /errorreport:prompt /warn:4 /define:DEBUG;TRACE /errorendlocation /preferreduilang:en -US /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\mscorlib.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\Microsoft.CSharp.dll"/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\ Profile158\mscorlib.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Core.dll" /reference:"C:\Program文件 (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Net.dll" /reference:"C:\Program Files (x86) \Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Runtime.Serialization.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4. 0\Profile\Profile158\System.ServiceModel.dll"/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.ServiceModel.Web.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Windows.dll" /reference:"C:\Program Files (x86)\Reference程序集\Microsoft\Framework.NETPortable\v4。0\Profile\Profile158\System.Xml.dll"/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Xml.Linq.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Xml.Serialization.dll" /debug+ /debug:full /filealign:512 /optimize - /out:obj\Debug\LibraryOfModels.dll /target:library /utf8output BuyMenuClass.cs CastleModel.cs ChampionModel.cs ChatDTO.cs CollectionCombiner.cs Country.cs CurrentUser.cs DecorationListItems.cs GameDTO.cs MapTransform.cs MarketplaceModel.cs MenuFirstPageModel.cs NotifyBase.cs Player.cs PopupColorPickerModel.cs PopupExtraInfoModel.cs PopUpModel.cs Properties\AssemblyInfo.cs RankingDTO.cs RankingModel.cs ShieldGearModel.cs UnitModel.cs UserDTO.cs WarCalculations.cs "C:\Users\Jonas\AppData\Local\Temp.NETPortable,Version=v4.0,Profile=Profile158.AssemblyAttributes.cs"

从 VS 2015 赢 10

C:\Program Files (x86)\MSBuild\14.0\bin\csc.exe /noconfig /nowarn:1701,1702,2008 /nostdlib+ /errorreport:prompt /warn:4 /define:DEBUG;TRACE /errorendlocation /preferreduilang:en -US /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\mscorlib.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\Microsoft.CSharp.dll"/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\ Profile158\mscorlib.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Core.dll" /reference:"C:\Program文件 (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Net.dll" /reference:"C:\Program Files (x86) \Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Runtime.Serialization.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4. 0\Profile\Profile158\System.ServiceModel.dll"/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.ServiceModel.Web.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Windows.dll" /reference:"C:\Program Files (x86)\Reference程序集\Microsoft\Framework.NETPortable\v4。0\Profile\Profile158\System.Xml.dll"/reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Xml.Linq.dll" /reference:"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETPortable\v4.0\Profile\Profile158\System.Xml.Serialization.dll" /debug+ /debug:full /filealign:512 /optimize - /out:obj\Debug\LibraryOfModels.dll /ruleset:"C:\Program Files (x86)\Microsoft Visual Studio 14.0\Team Tools\Static Analysis Tools\Rule Sets\MinimumRecommendedRules.ruleset" /target:library /utf8output BuyMenuClass .cs CastleModel.cs ChampionModel.cs ChatDTO.cs CollectionCombiner.cs Country.cs CurrentUser.cs DecorationListItems.cs GameDTO.cs MapTransform.cs MarketplaceModel.cs MenuFirstPageModel.cs NotifyBase.cs Player.cs PopupColorPickerModel。cs PopupExtraInfoModel.cs PopUpModel.cs Properties\AssemblyInfo.cs RankingDTO.cs RankingModel.cs ShieldGearModel.cs UnitModel.cs UserDTO.cs WarCalculations.cs "C:\Users\johann\AppData\Local\Temp.NETPortable,Version=v4. 0,Profile=Profile158.AssemblyAttributes.cs"

我们可以看到两者之间的唯一区别是使用的 .NetFrameworks。一个版本为 4.5.51650，另一个使用 4.6.01038。

更新

似乎最新的 win 10 更新已经解决了这个问题。

Answer 1

我只是猜测，因为您还没有发布错误消息本身。通常，除了评论中提到的默认 .NET 运行时版本之外，VS2013 和 VS2015 之间应该没有区别。

但看看代码，静态部分可能是问题所在

VisualTreeHelper.GetParent(o);

有时，在对象初始化和使用之前需要遵循一些顺序。

查看您的方法在哪里被调用也会很有帮助。

但是我通过搜索 VisualTreeHelper.GetParent null 在谷歌中找到了这个

VisualTreeHelper.GetParent 返回 null