Json序列化提示缺少编译器要求的成员“ystem.Runtime.CompilerServices.ExtensionAttribute..ctor”
//缺少编译器要求的成员“ystem.Runtime.CompilerServices.ExtensionAttribute..ctor” namespace System.Runtime.CompilerServices { public class ExtensionAttribute : Attribute { } }
//缺少编译器要求的成员“ystem.Runtime.CompilerServices.ExtensionAttribute..ctor” namespace System.Runtime.CompilerServices { public class ExtensionAttribute : Attribute { } }