Asp.net core ASP.NET核心从正文反序列化，带默认值_Asp.net Core_Json.net_Deserialization_Asp.net Core Webapi

Asp.net core ASP.NET核心从正文反序列化，带默认值

asp.net-core

Asp.net core ASP.NET核心从正文反序列化，带默认值,asp.net-core,json.net,deserialization,asp.net-core-webapi,Asp.net Core,Json.net,Deserialization,Asp.net Core Webapi,我有以下控制器（缩写）： Id是guid形式的字符串。如果从客户端传入一个，我应该使用给定的Id。如果没有从客户端传入值，我应该生成一个新的guid并使用它但是，当客户端没有给出任何值时，我无法让它使用默认值。不管怎样，它最终都是一个空字符串。我可以调试并观察它命中属性并为默认值生成一个新的guid，该guid会被调用setter的空字符串立即覆盖我在Startup.cs中的SerializerSettings上尝试了NullValueHandling和DefaultValueHandlin

我有以下控制器（缩写）：

Id

是guid形式的字符串。如果从客户端传入一个，我应该使用给定的Id。如果没有从客户端传入值，我应该生成一个新的guid并使用它

但是，当客户端没有给出任何值时，我无法让它使用默认值。不管怎样，它最终都是一个空字符串。我可以调试并观察它命中属性并为默认值生成一个新的guid，该guid会被调用setter的空字符串立即覆盖

我在

Startup.cs

中的

SerializerSettings

上尝试了

NullValueHandling

和

DefaultValueHandling

的不同值，但这没有帮助。如果我在

Id

属性上设置

[必需]

，我会收到一个ModelState错误，告诉我尝试的值是

null

，而不是空字符串

如何让它接受默认值

CONNECTServiceRegistry.dll!CONNECTServiceRegistry.Models.JsonServiceEntity.Id.set(string value) Line 45 C#
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.ExpressionValueProvider.SetValue(object target, object value) Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(Newtonsoft.Json.Serialization.JsonProperty property, Newtonsoft.Json.JsonConverter propertyConverter, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerProperty, Newtonsoft.Json.JsonReader reader, object target)    Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(object newObject, Newtonsoft.Json.JsonReader reader, Newtonsoft.Json.Serialization.JsonObjectContract contract, Newtonsoft.Json.Serialization.JsonProperty member, string id) Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, object existingValue) Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, object existingValue)  Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(Newtonsoft.Json.JsonReader reader, System.Type objectType, bool checkAdditionalContent)  Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.JsonSerializer.DeserializeInternal(Newtonsoft.Json.JsonReader reader, System.Type objectType)   Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.JsonSerializer.Deserialize(Newtonsoft.Json.JsonReader reader, System.Type objectType)   Unknown
Microsoft.AspNetCore.Mvc.Formatters.Json.dll!Microsoft.AspNetCore.Mvc.Formatters.JsonInputFormatter.ReadRequestBodyAsync(Microsoft.AspNetCore.Mvc.Formatters.InputFormatterContext context, System.Text.Encoding encoding) Line 303 C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Formatters.TextInputFormatter.ReadRequestBodyAsync(Microsoft.AspNetCore.Mvc.Formatters.InputFormatterContext context) Line 57    C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Formatters.InputFormatter.ReadAsync(Microsoft.AspNetCore.Mvc.Formatters.InputFormatterContext context) Line 116  C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.ModelBinding.Binders.BodyModelBinder.BindModelAsync(Microsoft.AspNetCore.Mvc.ModelBinding.ModelBindingContext bindingContext) Line 158   C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.ModelBinding.ParameterBinder.BindModelAsync(Microsoft.AspNetCore.Mvc.ActionContext actionContext, Microsoft.AspNetCore.Mvc.ModelBinding.IModelBinder modelBinder, Microsoft.AspNetCore.Mvc.ModelBinding.IValueProvider valueProvider, Microsoft.AspNetCore.Mvc.Abstractions.ParameterDescriptor parameter, Microsoft.AspNetCore.Mvc.ModelBinding.ModelMetadata metadata, object value) Line 239  C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ControllerBinderDelegateProvider.CreateBinderDelegate.__Bind|0(Microsoft.AspNetCore.Mvc.ControllerContext controllerContext, object controller, System.Collections.Generic.Dictionary<string, object> arguments) Line 77    C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.BindArgumentsAsync() Line 424   C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(ref Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.State next, ref Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Scope scope, ref object state, ref bool isCompleted) Line 69   C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync() Line 385   C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(ref Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.State next, ref Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Scope scope, ref object state, ref bool isCompleted) Line 692  C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter() Line 793 C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(ref Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.State next, ref Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Scope scope, ref object state, ref bool isCompleted) Line 407  C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync() Line 123    C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync() Line 81   C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.MvcAttributeRouteHandler.RouteAsync.AnonymousMethod__0(Microsoft.AspNetCore.Http.HttpContext c) Line 105    C#

CONNECTServiceRegistry.dll！CONNECTServiceRegistry.Models.JsonServiceEntity.Id.set（字符串值）第45行C#
Newtonsoft.Json.dll！Newtonsoft.Json.Serialization.ExpressionValueProvider.SetValue（对象目标，对象值）未知
Newtonsoft.Json.dll！Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue（Newtonsoft.Json.Serialization.JsonProperty属性，Newtonsoft.Json.Json转换器属性Converter，Newtonsoft.Json.Serialization.JsonContainerContract容器合同，Newtonsoft.Json.Serialization.JsonProperty容器属性，Newtonsoft.Json.JsonReader，对象目标）未知
Newtonsoft.Json.dll！Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject（对象newObject，Newtonsoft.Json.JsonReader，Newtonsoft.Json.Serialization.jsonObject合同，Newtonsoft.Json.Serialization.JsonProperty成员，字符串id）未知
Newtonsoft.Json.dll！Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject（Newtonsoft.Json.JsonReader阅读器，System.Type objectType，Newtonsoft.Json.Serialization.JsonContract契约，Newtonsoft.Json.Serialization.JsonProperty成员，Newtonsoft.Json.Serialization.JsonContainerContract containerContract，Newtonsoft.Json.Serialization.JsonProperty containerMember，object existingValue）未知
Newtonsoft.Json.dll！Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal（Newtonsoft.Json.JsonReader阅读器，System.Type objectType，Newtonsoft.Json.Serialization.JsonContract契约，Newtonsoft.Json.Serialization.JsonProperty成员，Newtonsoft.Json.Serialization.JsonContainerContract containerContract，Newtonsoft.Json.Serialization.JsonProperty containerMember，object existingValue）未知
Newtonsoft.Json.dll！Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize（Newtonsoft.Json.JsonReader reader，System.Type objectType，bool checkAdditionalContent）未知
Newtonsoft.Json.dll！Newtonsoft.Json.JsonSerializer.DeserializeInternal（Newtonsoft.Json.JsonReader，System.Type objectType）未知
Newtonsoft.Json.dll！Newtonsoft.Json.JsonSerializer.Deserialize（Newtonsoft.Json.JsonReader reader，System.Type objectType）未知
Microsoft.AspNetCore.Mvc.Formatters.Json.dll！Microsoft.AspNetCore.Mvc.Formatters.JsonInputFormatter.ReadRequestBodyAsync（Microsoft.AspNetCore.Mvc.Formatters.InputFormatter上下文，System.Text.Encoding编码）第303行#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Formatters.TextInputFormatter.ReadRequestBodyAsync（Microsoft.AspNetCore.Mvc.Formatters.InputFormatters上下文）第57行#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Formatters.InputFormatter.ReadAsync（Microsoft.AspNetCore.Mvc.Formatters.InputFormatter上下文）第116行#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.ModelBinding.Binders.BodyModelBinder.BindModelAsync（Microsoft.AspNetCore.Mvc.ModelBinding.ModelBindingContext bindingContext）第158C行#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.ModelBinding.ParameterBinder.BindModelAsync（Microsoft.AspNetCore.Mvc.ActionContext ActionContext、Microsoft.AspNetCore.Mvc.ModelBinding.IModelBinder modelBinder、Microsoft.AspNetCore.Mvc.ModelBinding.IValueProvider valueProvider、Microsoft.AspNetCore.Mvc.ModelBinding.ModelMetadata元数据、对象值）第239行#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Internal.ControllerBinderDelegateProvider.CreateBinderDelegate.|绑定| 0（Microsoft.AspNetCore.Mvc.ControllerContext ControllerContext，对象控制器，System.Collections.Generic.Dictionary参数）第77行#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.BindArgumentsSync（）行424 C#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next（参考Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.State Next，参考Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Scope范围，参考对象状态，参考布尔已完成）第69行C#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync（）行385 C#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next（参考Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.State Next，参考Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Scope范围，参考对象状态，参考bool isCompleted）第692 C行#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter（）行793 C#
Microsoft.AspNetCore.Mvc.Core.dll！Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next（参考Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.State Next，参考Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Scope范围，参考对象状态，参考bool isCompleted）第407 C行#
微软
public class JsonServiceEntity
{
    public string Id { get; set; } = Guid.NewGuid().ToString();
}

CONNECTServiceRegistry.dll!CONNECTServiceRegistry.Models.JsonServiceEntity.Id.set(string value) Line 45 C#
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.ExpressionValueProvider.SetValue(object target, object value) Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(Newtonsoft.Json.Serialization.JsonProperty property, Newtonsoft.Json.JsonConverter propertyConverter, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerProperty, Newtonsoft.Json.JsonReader reader, object target)    Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(object newObject, Newtonsoft.Json.JsonReader reader, Newtonsoft.Json.Serialization.JsonObjectContract contract, Newtonsoft.Json.Serialization.JsonProperty member, string id) Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, object existingValue) Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(Newtonsoft.Json.JsonReader reader, System.Type objectType, Newtonsoft.Json.Serialization.JsonContract contract, Newtonsoft.Json.Serialization.JsonProperty member, Newtonsoft.Json.Serialization.JsonContainerContract containerContract, Newtonsoft.Json.Serialization.JsonProperty containerMember, object existingValue)  Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(Newtonsoft.Json.JsonReader reader, System.Type objectType, bool checkAdditionalContent)  Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.JsonSerializer.DeserializeInternal(Newtonsoft.Json.JsonReader reader, System.Type objectType)   Unknown
Newtonsoft.Json.dll!Newtonsoft.Json.JsonSerializer.Deserialize(Newtonsoft.Json.JsonReader reader, System.Type objectType)   Unknown
Microsoft.AspNetCore.Mvc.Formatters.Json.dll!Microsoft.AspNetCore.Mvc.Formatters.JsonInputFormatter.ReadRequestBodyAsync(Microsoft.AspNetCore.Mvc.Formatters.InputFormatterContext context, System.Text.Encoding encoding) Line 303 C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Formatters.TextInputFormatter.ReadRequestBodyAsync(Microsoft.AspNetCore.Mvc.Formatters.InputFormatterContext context) Line 57    C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Formatters.InputFormatter.ReadAsync(Microsoft.AspNetCore.Mvc.Formatters.InputFormatterContext context) Line 116  C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.ModelBinding.Binders.BodyModelBinder.BindModelAsync(Microsoft.AspNetCore.Mvc.ModelBinding.ModelBindingContext bindingContext) Line 158   C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.ModelBinding.ParameterBinder.BindModelAsync(Microsoft.AspNetCore.Mvc.ActionContext actionContext, Microsoft.AspNetCore.Mvc.ModelBinding.IModelBinder modelBinder, Microsoft.AspNetCore.Mvc.ModelBinding.IValueProvider valueProvider, Microsoft.AspNetCore.Mvc.Abstractions.ParameterDescriptor parameter, Microsoft.AspNetCore.Mvc.ModelBinding.ModelMetadata metadata, object value) Line 239  C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ControllerBinderDelegateProvider.CreateBinderDelegate.__Bind|0(Microsoft.AspNetCore.Mvc.ControllerContext controllerContext, object controller, System.Collections.Generic.Dictionary<string, object> arguments) Line 77    C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.BindArgumentsAsync() Line 424   C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(ref Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.State next, ref Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Scope scope, ref object state, ref bool isCompleted) Line 69   C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync() Line 385   C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(ref Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.State next, ref Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Scope scope, ref object state, ref bool isCompleted) Line 692  C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter() Line 793 C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(ref Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.State next, ref Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Scope scope, ref object state, ref bool isCompleted) Line 407  C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync() Line 123    C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync() Line 81   C#
Microsoft.AspNetCore.Mvc.Core.dll!Microsoft.AspNetCore.Mvc.Internal.MvcAttributeRouteHandler.RouteAsync.AnonymousMethod__0(Microsoft.AspNetCore.Http.HttpContext c) Line 105    C#

public class JsonServiceEntity
{
    [DefaultValue("")]
    public string Id { get; set; } = Guid.NewGuid().ToString();
}

DefaultValueHandling = DefaultValueHandling.Ignore

public string Id { get; set; } = Guid.NewGuid().ToString();

{
    "id": "",
    "name": "foo"
}

{
    "name": "foo"
}

private string id;
public string Id
{
    get => id;
    set => id = string.IsNullOrWhiteSpace(value) ? Guid.NewGuid().ToString() : value;
}