为什么 BindNever 属性不起作用

问题描述

我不想在我的 CustomerViewModel 上绑定 Id 属性，所以我添加了一个 [BindNever] 属性，但它不起作用.有什么解决办法?

I do not want do bind the Id property on my CustomerViewModel so I added a [BindNever] attribute but it is not working. What could be the solution?

我有以下几点:

CustomerController.cs

// PUT api/customers/5
[HttpPut("{id}")]
public async Task<IActionResult> Put([FromUri] int id, [FromBody]CustomerViewModel customer)
{
  //Implementation
}

客户视图模型

public class CustomerViewModel
{
    [BindNever]
    public int Id { get; set; }
    public string LastName { get; set; }
    public string FirstName { get; set; }
    public string Email { get; set; }
}

如果我输入以下 json .id 属性仍然被绑定

If I input the following json . The id property still gets binded

{
  "id": 100,
  "lastName": "Bruce",
  "firstName": "Wayne",
  "email": "bruce@gothamcity.com"
}

推荐答案

这个 博文读起来很有趣，并得出结论，[FromBody] 注释覆盖"了BindBehaviourAttribute(BindNever 是一个简单的特化).该模型由正文中的所有可用数据(在本例中为您的 JSON 数据)填充.

This Blog post is an interesting read and concludes that the [FromBody] annotation "overrides" the BindBehaviourAttribute (BindNever is a simple specialization). The model is populated by all data available from the body (your JSON data in this case).

我不认为这是直观的，issue 有一个很好的声明关于这个:

I do not consider this as intuitive, and the issue has a nice statement about this:

[BindRequired] 自定义MVC模型绑定系统.这就是它目的并按设计工作.

[BindRequired] customizes the MVC model binding system . That's its purpose and it's working as designed.

[FromBody] 将受影响的属性或参数切换到输入格式的不同世界.每个输入格式化程序(例如Json.NET 和一个小型的 MVC 特定包装器)可以被认为是一个具有自己定制的独立系统.模型绑定系统不知道 JSON(或任何其他)反序列化的细节.

[FromBody] switches the affected property or parameter into the different world of input formatting. Each input formatter (e.g. Json.NET and a small MVC-specific wrapper) can be considered a separate system with its own customization. The model binding system has no knowledge the details of JSON (or any other) deserialization.

经验教训:BindNever 在这种情况下不起作用.

Lesson learned: BindNever does not work in this scenario.

什么是替代品?

解决方案 1:编写一些自定义模型绑定代码.我自己没有做过，但是 在 MVC6 中创建自定义模型绑定器的正确方法是什么? 可能会有所帮助.

Solution 1: Writing some custom model binding code. I have not done it myself, but What is the correct way to create custom model binders in MVC6? may help.

解决方案 2:比较务实的解决方案

Solution 2: Rather pragmatic one

也许这个简单(但不是很好)的解决方法可以帮助您:

Perhaps this simple (but not very nice) workaround helps you out:

[HttpPut("{id}")]
public async Task<IActionResult> Put([FromUri] int id, [FromBody]CustomerViewModel customer)
{
    customer.Id = 0;
    //Implementation
}

这篇关于为什么 BindNever 属性不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！