C#中如何无需自定义类重写公共库SwaggerDocument的Json.NET注解？

Got it, let's work through this. You're using a public SwaggerDocument class with hardcoded Newtonsoft.Json serialization annotations (like the JsonProperty attribute controlling DefaultValueHandling, Order, and PropertyName), and you want to adjust those settings without having to build a custom wrapper or derived class—totally get it, duplicating code just to tweak serialization rules is a hassle.

Here's the cleanest approach using Newtonsoft's ContractResolver feature, which lets you dynamically override serialization contracts at runtime:

Step 1: Build a Custom Contract Resolver #

The DefaultContractResolver is Newtonsoft's core tool for defining how types are serialized. We'll subclass it to override the rules specifically for the SwaggerDocument properties you care about:

using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
using System.Reflection;

public class CustomSwaggerContractResolver : DefaultContractResolver
{
    protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
    {
        // Start with the original contract defined by the library's annotations
        JsonProperty property = base.CreateProperty(member, memberSerialization);

        // Target the specific property you want to modify
        if (member.DeclaringType == typeof(SwaggerDocument) && member.Name == nameof(SwaggerDocument.BasePath))
        {
            // Override settings to your desired values
            property.DefaultValueHandling = DefaultValueHandling.Include; // Replace with your preferred rule
            property.Order = 3; // Adjust serialization order
            property.PropertyName = "custom_base_path"; // Rename the JSON property if needed
            // You can also add tweaks like NullValueHandling here
        }

        // Add more conditions here if you need to modify other SwaggerDocument properties
        // Example: if (member.Name == nameof(SwaggerDocument.Title)) { ... }

        return property;
    }
}

Step 2: Use the Resolver During Serialization/Deserialization #

When you need to process a SwaggerDocument instance, pass your custom resolver into the JsonSerializerSettings:

// Initialize your SwaggerDocument instance
var swaggerDoc = new SwaggerDocument { BasePath = "/api/v1" };

// Configure serialization with your modified rules
var jsonSettings = new JsonSerializerSettings
{
    ContractResolver = new CustomSwaggerContractResolver(),
    Formatting = Formatting.Indented // Optional: for pretty-printed JSON
};

// Serialize using the adjusted rules
string serializedJson = JsonConvert.SerializeObject(swaggerDoc, jsonSettings);

// Or deserialize with the same rules if needed
SwaggerDocument deserializedDoc = JsonConvert.DeserializeObject<SwaggerDocument>(jsonString, jsonSettings);

Step 3: Integrate with ASP.NET Core (If Using Swashbuckle) #

If you're working in an ASP.NET Core project with Swashbuckle (Swagger), you can set up the resolver globally so Swagger uses your custom serialization rules:

services.AddSwaggerGen(c =>
{
    c.SwaggerDoc("v1", new OpenApiInfo { Title = "My API", Version = "v1" });
});

// Configure Newtonsoft.Json settings for controllers and Swagger
services.AddControllers()
    .AddNewtonsoftJson(options =>
    {
        options.SerializerSettings.ContractResolver = new CustomSwaggerContractResolver();
    });

Why This Works #

• No custom class required: You're modifying behavior dynamically instead of creating a wrapper or derived class.
• Non-intrusive: The original SwaggerDocument class stays untouched, so other parts of your code that use it (without the resolver) will still behave as expected.
• Flexible: You can tweak multiple properties, add conditional logic, or apply global rules for the entire SwaggerDocument type.

内容的提问来源于stack exchange，提问作者user171943