在ASP.NET Core 2.2中嵌套属性的模型绑定

本文介绍了在ASP.NET Core 2.2中嵌套属性的模型绑定的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在尝试为我的模型(动作参数)创建一个通用的复杂对象，并在许多地方重复使用.

I'm trying to create a common complex object for my models (action parameters) and reuse it in many places.

以下是一些示例代码:

[HttpGet("/api/values")] public ActionResult<string> Get([FromQuery] MyModel model) { var sb = new StringBuilder(); sb.AppendLine(model.Id); sb.AppendLine($"{model.Id}-{model.Generated?.DateStart}-{model.Generated?.DateEnd}"); sb.AppendLine($"{model.Id}-{model.Reference?.DateStart}-{model.Reference?.DateEnd}"); return sb.ToString(); } public class MyModel { public string Id { get; set; } public DateInfo Generated { get; set; } = new DateInfo(); public DateInfo Reference { get; set; } = new DateInfo(); } public class DateInfo { public DateTime? DateStart { get; set; } public DateTime? DateEnd { get; set; } public RelativeTime? RelativeTime { get; set; } }

想象一下，DateInfo类将具有可在许多模型中使用的验证和通用属性.

Imagine the DateInfo class would have validation and common properties to be used in many models.

在嵌套属性中添加[FromQuery(Name = "Something")]可以使您大摇大摆，但是却无法拥有两个具有相同类型的嵌套属性.

Adding [FromQuery(Name = "Something")] to the nested properties does the trick for swagger, but it makes it impossible to have two nested properties with the same type.

我知道添加完全限定的属性名称( .../values?Id = 1& Generated.DateInfo = 2& Reference.DateInfo = 3 )可以使其正常工作，但这可以是调用任何API的一种非常丑陋的方式.连字符是方式，不是点.

I understand that adding the fully qualified property name (.../values?Id=1&Generated.DateInfo=2&Reference.DateInfo=3) would make it work, but that would be a really ugly way to call any API. Hyphens are the way, not dots.

我想以与映射常规属性相同的方式来映射绑定.

I would like to map the binding in the same way as mapping a regular property.

如何实现?

推荐答案

我看到两个选择.

选项1:只需创建一个新的扁平化类{Id, Foo, Bar}用作操作方法的参数即可.然后，您可以将其映射到MyModel.这是我建议最可维护的方法.

Option 1: Just create a new, flattened class {Id, Foo, Bar} to use as the parameter of your action method. You can then map that to MyModel. That's the approach I would recommend as most maintainable.

选项2:自定义模型绑定，如下所示:

Option 2: Custom model binding, as follows:

[ModelBinder(BinderType = typeof(MyModelBinder))] public class MyModel { public string Id { get; set; } [FromQuery] public Info ComplexNestedProperty { get; set; } } public class AuthorEntityBinder : IModelBinder { public Task BindModelAsync(ModelBindingContext bindingContext) { var model = new MyModel { Id = bindingContext.ValueProvider.GetValue("id"), ComplexNestedProperty = new Info { Foo = bindingContext.ValueProvider.GetValue("foo"), Bar = bindingContext.ValueProvider.GetValue("bar") } }; bindingContext.Result = ModelBindingResult.Success(model); return Task.CompletedTask; } }

作为选项2 的扩展，您可以合理地编写一些反射来获取嵌套模型的所有叶子属性名称.

As an expansion on Option 2 you could reasonably write some reflection that gets all the leaf property names of your nested model.