Protobuf-net 无法序列化 属性 只有 getter - 无法将更改应用到 属性
Protobuf-net fails to serialize property with only getter - Cannot apply changes to property
我正在使用 protobuf-net 序列化一个对象,但出现异常:
无法将更改应用到 属性 TestProject.TestMessage.ClientId
使用堆栈跟踪:
at ProtoBuf.Serializers.PropertyDecorator.SanityCheck(TypeModel model, PropertyInfo property, IProtoSerializer tail, Boolean& writeValue, Boolean nonPublic, Boolean allowInternal)
at ProtoBuf.Serializers.PropertyDecorator..ctor(TypeModel model, Type forType, PropertyInfo property, IProtoSerializer tail)
at ProtoBuf.Meta.ValueMember.BuildSerializer()
at ProtoBuf.Meta.ValueMember.get_Serializer()
at ProtoBuf.Meta.MetaType.BuildSerializer()
at ProtoBuf.Meta.MetaType.get_Serializer()
at ProtoBuf.Meta.RuntimeTypeModel.Serialize(Int32 key, Object value, ProtoWriter dest)
at ProtoBuf.Meta.TypeModel.SerializeCore(ProtoWriter writer, Object value)
at ProtoBuf.Meta.TypeModel.Serialize(Stream dest, Object value, SerializationContext context)
at ProtoBuf.Meta.TypeModel.Serialize(Stream dest, Object value)
at ProtoBuf.Serializer.Serialize[T](Stream destination, T instance)
我的class如下:
[DataContract]
public class TestMessage
{
private int clientId;
[DataMember(Order = 1)]
public int ClientId
{
get { return clientId; }
}
private string name;
[DataMember(Order = 2)]
public string Name
{
get { return name; }
}
public TestMessage(int clientId,
string name)
{
this.clientId = clientId;
this.name =name;
}
}
是的,这是正确的:protobuf-net 无法成功往返一个只获取的 属性,例如您的 ClientId
,因此会抛出一个异常,试图构建一个显式的合约需要这样的 属性 序列化。
并非只有此限制。我注意到您正在使用数据协定属性标记您的类型。如果我尝试使用 DataContractSerializer
序列化它的一个实例,它会失败并出现一个等效的异常:
System.Runtime.Serialization.InvalidDataContractException was caught
Message="No set method for property 'ClientId' in type 'Question40276317.V1.TestMessage'."
Source="System.Runtime.Serialization"
如果您只想跳过 get-only 属性,请将它们标记为 [IgnoreDataMember]
。如果你想成功地序列化和反序列化它们,你有以下选择。
首先,protobuf-net 需要能够构造您的对象。与 Json.NET 不同,它不会调用参数化构造函数,因此最简单的做法是添加无参数构造函数。只要它存在,它就可以是私有的或受保护的(在完整框架上)。或者,您可以设置 [ProtoContract(SkipConstructor = true)]
,但这并不适用于所有框架或部分信任情况。
接下来,您需要以某种方式设置属性。一种解决方案是添加私有设置器:
[DataContract]
public class TestMessage
{
private int clientId;
[DataMember(Order = 1)]
public int ClientId
{
get { return clientId; }
private set { clientId = value; }
}
private string name;
[DataMember(Order = 2)]
public string Name
{
get { return name; }
private set { name = value; }
}
protected TestMessage() { }
public TestMessage(int clientId, string name)
{
this.clientId = clientId;
this.name = name;
}
}
另一种方法是标记基础字段而不是具有数据协定属性的属性:
[DataContract]
public class TestMessage
{
[DataMember(Name = "ClientId", Order = 1)]
private int clientId;
public int ClientId
{
get { return clientId; }
}
[DataMember(Name = "Name", Order = 2)]
private string name;
public string Name
{
get { return name; }
}
protected TestMessage() { }
public TestMessage(int clientId, string name)
{
this.clientId = clientId;
this.name = name;
}
}
或者,如果您真的希望 clientId
和 name
的值在构建后不可变,您将需要一个序列化代理,如下所示:
public class TestMessage
{
private readonly int clientId;
public int ClientId
{
get { return clientId; }
}
private readonly string name;
public string Name
{
get { return name; }
}
public TestMessage(int clientId, string name)
{
this.clientId = clientId;
this.name = name;
}
}
[DataContract]
internal class TestMessageSurrogate
{
public static implicit operator TestMessageSurrogate(TestMessage message)
{
if (message == null)
return null;
return new TestMessageSurrogate { ClientId = message.ClientId, Name = message.Name };
}
public static implicit operator TestMessage(TestMessageSurrogate message)
{
if (message == null)
return null;
return new TestMessage(message.ClientId, message.Name);
}
[DataMember(Order = 1)]
public int ClientId { get; set; }
[DataMember(Order = 2)]
public string Name { get; set; }
}
然后,在序列化之前,做:
ProtoBuf.Meta.RuntimeTypeModel.Default.Add(typeof(TestMessage), true).SetSurrogate(typeof(TestMessageSurrogate));
通过使用代理项,您还可以避免使用任何无参数构造函数。
我正在使用 protobuf-net 序列化一个对象,但出现异常:
无法将更改应用到 属性 TestProject.TestMessage.ClientId
使用堆栈跟踪:
at ProtoBuf.Serializers.PropertyDecorator.SanityCheck(TypeModel model, PropertyInfo property, IProtoSerializer tail, Boolean& writeValue, Boolean nonPublic, Boolean allowInternal)
at ProtoBuf.Serializers.PropertyDecorator..ctor(TypeModel model, Type forType, PropertyInfo property, IProtoSerializer tail)
at ProtoBuf.Meta.ValueMember.BuildSerializer()
at ProtoBuf.Meta.ValueMember.get_Serializer()
at ProtoBuf.Meta.MetaType.BuildSerializer()
at ProtoBuf.Meta.MetaType.get_Serializer()
at ProtoBuf.Meta.RuntimeTypeModel.Serialize(Int32 key, Object value, ProtoWriter dest)
at ProtoBuf.Meta.TypeModel.SerializeCore(ProtoWriter writer, Object value)
at ProtoBuf.Meta.TypeModel.Serialize(Stream dest, Object value, SerializationContext context)
at ProtoBuf.Meta.TypeModel.Serialize(Stream dest, Object value)
at ProtoBuf.Serializer.Serialize[T](Stream destination, T instance)
我的class如下:
[DataContract]
public class TestMessage
{
private int clientId;
[DataMember(Order = 1)]
public int ClientId
{
get { return clientId; }
}
private string name;
[DataMember(Order = 2)]
public string Name
{
get { return name; }
}
public TestMessage(int clientId,
string name)
{
this.clientId = clientId;
this.name =name;
}
}
是的,这是正确的:protobuf-net 无法成功往返一个只获取的 属性,例如您的 ClientId
,因此会抛出一个异常,试图构建一个显式的合约需要这样的 属性 序列化。
并非只有此限制。我注意到您正在使用数据协定属性标记您的类型。如果我尝试使用 DataContractSerializer
序列化它的一个实例,它会失败并出现一个等效的异常:
System.Runtime.Serialization.InvalidDataContractException was caught
Message="No set method for property 'ClientId' in type 'Question40276317.V1.TestMessage'."
Source="System.Runtime.Serialization"
如果您只想跳过 get-only 属性,请将它们标记为 [IgnoreDataMember]
。如果你想成功地序列化和反序列化它们,你有以下选择。
首先,protobuf-net 需要能够构造您的对象。与 Json.NET 不同,它不会调用参数化构造函数,因此最简单的做法是添加无参数构造函数。只要它存在,它就可以是私有的或受保护的(在完整框架上)。或者,您可以设置 [ProtoContract(SkipConstructor = true)]
,但这并不适用于所有框架或部分信任情况。
接下来,您需要以某种方式设置属性。一种解决方案是添加私有设置器:
[DataContract]
public class TestMessage
{
private int clientId;
[DataMember(Order = 1)]
public int ClientId
{
get { return clientId; }
private set { clientId = value; }
}
private string name;
[DataMember(Order = 2)]
public string Name
{
get { return name; }
private set { name = value; }
}
protected TestMessage() { }
public TestMessage(int clientId, string name)
{
this.clientId = clientId;
this.name = name;
}
}
另一种方法是标记基础字段而不是具有数据协定属性的属性:
[DataContract]
public class TestMessage
{
[DataMember(Name = "ClientId", Order = 1)]
private int clientId;
public int ClientId
{
get { return clientId; }
}
[DataMember(Name = "Name", Order = 2)]
private string name;
public string Name
{
get { return name; }
}
protected TestMessage() { }
public TestMessage(int clientId, string name)
{
this.clientId = clientId;
this.name = name;
}
}
或者,如果您真的希望 clientId
和 name
的值在构建后不可变,您将需要一个序列化代理,如下所示:
public class TestMessage
{
private readonly int clientId;
public int ClientId
{
get { return clientId; }
}
private readonly string name;
public string Name
{
get { return name; }
}
public TestMessage(int clientId, string name)
{
this.clientId = clientId;
this.name = name;
}
}
[DataContract]
internal class TestMessageSurrogate
{
public static implicit operator TestMessageSurrogate(TestMessage message)
{
if (message == null)
return null;
return new TestMessageSurrogate { ClientId = message.ClientId, Name = message.Name };
}
public static implicit operator TestMessage(TestMessageSurrogate message)
{
if (message == null)
return null;
return new TestMessage(message.ClientId, message.Name);
}
[DataMember(Order = 1)]
public int ClientId { get; set; }
[DataMember(Order = 2)]
public string Name { get; set; }
}
然后,在序列化之前,做:
ProtoBuf.Meta.RuntimeTypeModel.Default.Add(typeof(TestMessage), true).SetSurrogate(typeof(TestMessageSurrogate));
通过使用代理项,您还可以避免使用任何无参数构造函数。