[[Query]对象的Asp.Net核心如何使用DataMember名称，ModelBinding

Question

对于[FromBody]参数，我可以使用DataMember.Name设置属性的自定义名称，但不适用于[FromQuery]。我想这取决于模型绑定

我想处理类似?status=a&status=b&status=c的查询

带有查询对象[FromQuery]MyQuery

[DataContract]
class MyQuery {
     [DataMember(Name = "status")
     public IReadOnlyList<string> Statuses { get; set; }
}

我可以做到

class MyQuery {
     [FromQuery("status")
     public IReadOnlyList<string> Statuses { get; set; }
}

但是我想避免AspNetCore对模型的依赖性，有什么解决方法吗？

（有similar question about Web API 2，但没有答案）

Answer 1

我没有找到使用标准属性的方法，所以我使用statuses名称，对字符串集合使用自定义属性

[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
internal class StringCollectionAttribute : Attribute
{
}

并使用自定义模型活页夹

public class StringCollectionBinderProvider : IModelBinderProvider
{
    private static readonly Type BinderType = typeof(StringCollectionBinder);
    private static readonly Type ModelType = typeof(List<string>);

    public IModelBinder GetBinder(ModelBinderProviderContext context)
    {
        if (context == null)
        {
            throw new ArgumentNullException(nameof(context));
        }

        var propertyAttributes = (context.Metadata as DefaultModelMetadata)?.Attributes.PropertyAttributes;

        var isStringCollection =
            propertyAttributes?.Any(x => x is StringCollectionAttribute) == true
            && context.Metadata.ModelType.IsAssignableFrom(ModelType);

        return isStringCollection ? new BinderTypeModelBinder(BinderType) : null;
    }
}

public class StringCollectionBinder : IModelBinder
{
    private const char ValueSeparator = ',';

    public Task BindModelAsync(ModelBindingContext bindingContext)
    {
        if (bindingContext == null)
        {
            throw new ArgumentNullException(nameof(bindingContext));
        }

        var modelName = bindingContext.ModelName;
        var valueCollection = bindingContext.ValueProvider.GetValue(modelName);

        if (valueCollection == ValueProviderResult.None)
        {
            return Task.CompletedTask;
        }

        bindingContext.ModelState.SetModelValue(modelName, valueCollection);

        var stringCollection = valueCollection.FirstValue;

        if (string.IsNullOrEmpty(stringCollection))
        {
            return Task.CompletedTask;
        }

        var collection = stringCollection.Split(ValueSeparator).ToList();
        bindingContext.Result = ModelBindingResult.Success(collection);
        return Task.CompletedTask;
    }
}