在使用AspNet.WebApi.Versioning库时,如果想要改变IEnumerable参数的模型绑定行为,可以通过重写DefaultQueryValueBinder类来实现。
首先,创建一个自定义的QueryValueBinder类,继承自DefaultQueryValueBinder类,并重写BindModel方法。在BindModel方法中,判断参数类型是否为IEnumerable,并进行相应的处理。
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.ModelBinding.Binders;
using Microsoft.Extensions.Logging;
using System;
using System.Globalization;
using System.Linq;
using System.Threading.Tasks;
namespace YourNamespace
{
public class CustomQueryValueBinder : DefaultQueryValueBinder
{
public CustomQueryValueBinder(IModelMetadataProvider metadataProvider, ILoggerFactory loggerFactory)
: base(metadataProvider, loggerFactory)
{
}
public override Task BindModelAsync(ModelBindingContext bindingContext)
{
if (bindingContext == null)
{
throw new ArgumentNullException(nameof(bindingContext));
}
var modelType = bindingContext.ModelType;
if (typeof(IEnumerable).IsAssignableFrom(modelType))
{
// 处理IEnumerable类型参数的绑定行为
var valueProviderResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
if (valueProviderResult != ValueProviderResult.None)
{
var values = valueProviderResult.Values.ToArray();
var elementType = modelType.GetGenericArguments().FirstOrDefault();
var elementBinder = GetBinder(elementType);
var bindingTasks = new Task[values.Length];
for (var i = 0; i < values.Length; i++)
{
var modelMetadata = bindingContext.ModelMetadata.GetMetadataForType(elementType);
var modelBindingContext = DefaultModelBindingContext.CreateBindingContext(
bindingContext.ActionContext,
bindingContext.ValueProvider,
modelMetadata,
bindingInfo: null,
bindingContext.ModelName);
modelBindingContext.Model = elementType.IsValueType ? Activator.CreateInstance(elementType) : null;
modelBindingContext.ModelType = elementType;
bindingTasks[i] = elementBinder.BindModelAsync(modelBindingContext);
}
return Task.WhenAll(bindingTasks).ContinueWith(t =>
{
var result = (Array)Array.CreateInstance(elementType, values.Length);
for (var i = 0; i < values.Length; i++)
{
result.SetValue(bindingTasks[i].Result.Model, i);
}
return ModelBindingResult.Success(result);
});
}
}
return base.BindModelAsync(bindingContext);
}
}
}
然后,在Startup.cs文件中的ConfigureServices方法中,使用AddMvcOptions扩展方法,并注册自定义的QueryValueBinder类。
using YourNamespace;
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc(options =>
{
options.ModelBinderProviders.Insert(0, new QueryStringValueProviderFactory());
options.ModelBinderProviders.Insert(0, new FormValueProviderFactory());
options.ModelBinderProviders.Insert(0, new BodyModelBinderProvider());
var binderToFind = options.ModelBinderProviders.FirstOrDefault(x => x.GetType() == typeof(QueryStringValueProviderFactory));
if (binderToFind != null)
{
options.ModelBinderProviders.Remove(binderToFind);
}
options.ModelBinderProviders.Insert(0, new CustomQueryValueBinderProvider());
});
//其他配置
}
最后,创建一个CustomQueryValueBinderProvider类,实现IModelBinderProvider接口,并返回自定义的QueryValueBinder类的实例。
using Microsoft.AspNetCore.Mvc.ModelBinding;
namespace YourNamespace
{
public class CustomQueryValueBinderProvider : IModelBinderProvider
{
public IModelBinder GetBinder(ModelBinderProviderContext context)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (context.Metadata.IsCollectionType)
{
return new CustomQueryValueBinder(context.Metadata.ModelType);
}
return null;
}
}
}
通过以上配置,AspNet.WebApi.Versioning库将使用自定义的QueryValueBinder类来处理IEnumerable参数的模型绑定行为。