unity中导入插件时报错处理办法

错误如下：

Unhandled Exception: System.TypeLoadException: Could not load type 'System.ComponentModel.InitializationEventAttribute' from assembly 'System.Windows.Forms'.

at (wrapper managed-to-native) System.MonoCustomAttrs:GetCustomAttributesInternal (System.Reflection.ICustomAttributeProvider,System.Type,bool)

at System.MonoCustomAttrs.GetCustomAttributesBase (ICustomAttributeProvider obj, System.Type attributeType) [0x00000] in <filename unknown>:0

at System.MonoCustomAttrs.GetCustomAttributes (ICustomAttributeProvider obj, System.Type attributeType, Boolean inherit) [0x00000] in <filename unknown>:0

at System.MonoType.GetCustomAttributes (System.Type attributeType, Boolean inherit) [0x00000] in <filename unknown>:0

at Mono.CSharp.AttributeTester.GetObsoleteAttribute (System.Type type) [0x00000] in <filename unknown>:0

at Mono.CSharp.Expression.ResolveAsTypeTerminal (IMemberContext ec, Boolean silent) [0x00000] in <filename unknown>:0

at Mono.CSharp.Expression.ResolveAsContextualType (IMemberContext rc, Boolean silent) [0x00000] in <filename unknown>:0

at Mono.CSharp.LocalInfo.Resolve (Mono.CSharp.ResolveContext ec) [0x00000] in <filename unknown>:0

at Mono.CSharp.Block.ResolveMeta (Mono.CSharp.BlockContext ec, Int32 offset) [0x00000] in <filename unknown>:0

at Mono.CSharp.ToplevelBlock.ResolveMeta (Mono.CSharp.BlockContext ec, Mono.CSharp.ParametersCompiled ip) [0x00000] in <filename unknown>:0

at Mono.CSharp.ToplevelBlock.Resolve (Mono.CSharp.FlowBranching parent, Mono.CSharp.BlockContext rc, Mono.CSharp.ParametersCompiled ip, IMethodData md) [0x00000] in <filename unknown>:0

Internal compiler error at Assets/VLC for Unity/Scripts/PlayVLC.cs(241,21):: exception caught while emitting MethodBuilder [PlayVLC::GetCurrentMonitorDesktopResolution]
The class System.Runtime.InteropServices.StandardOleMarshalObject could not be loaded, used in System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
The class System.Windows.Forms.Control could not be loaded, used in System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicK

因为 Mono 平台支持 .net 3.5，所以只能使用 NET2.0 的 newtonsoft.json.dll导致了此问题。

解决办法：

Unity 菜单 Edit->Project Settings->Player, 在 Player 设置里选择 Api Comatibility Level 从 .NET 2.0 Subset 改为 .NET 2.0。