Web API验证不会通过自定义模型绑定程序触发

Question

我正在使用Web API 5构建Web Service。我正在通过扩展IModelBinder接口来实现将自定义模型绑定程序映射为操作的复杂类型。绑定部分工作正常。但是不会发生模型验证。ModelState.IsValid始终为true。

public class PagingParamsVM
{
        [Range(1, Int32.MaxValue, ErrorMessage = "Page must be at least 1")]
        public int? Page { get; set; }

        [Range(1, Int32.MaxValue, ErrorMessage = "Page size must be at least 1")]
        public int? PageSize { get; set; }
}

public class PaginationModelBinder : IModelBinder
{
        public bool BindModel(HttpActionContext actionContext, ModelBindingContext bindingContext)
        {
              var model = (PagingParamsVM)bindingContext.Model ?? new PagingParamsVM();
              //model population logic
              .....

              bindingContext.Model = model;
              return true;
        }
}

public IEnumerable<NewsItemVM> Get([ModelBinder(typeof(PaginationModelBinder))]PagingParamsVM pegination)
{
            //Validate(pegination); //if I call this explicitly ModelState.IsValid is set correctly.
            var valid = ModelState.IsValid; //this is always true
}

public class ModelStateValidationActionFilter : ActionFilterAttribute
{
        public override void OnActionExecuting(HttpActionContext actionContext)
        {
            var valid = actionContext.ModelState.IsValid //this is always true.
        }
}

如果我显式调用Validate（）或使用[FromUri]属性，则将正确设置ModelState.IsValid。

public IEnumerable<NewsItemVM> Get([FromUri]PagingParamsVM pegination)
{
            var valid = ModelState.IsValid;
}

我应该在模型活页夹中实现验证部分吗？如果是这样，我应该如何实施？

Answer 1

我找到了答案。可以在自定义模型绑定器中调用默认验证过程，如下所示：

public abstract class PaginationModelBinder : IModelBinder
{
        public bool BindModel(HttpActionContext actionContext, ModelBindingContext bindingContext)
        {
              var model = (PagingParamsVM)bindingContext.Model ?? new PagingParamsVM();
              //model population logic
              .....

              bindingContext.Model = model;

              //following lines invoke default validation on model
              bindingContext.ValidationNode.ValidateAllProperties = true;
              bindingContext.ValidationNode.Validate(actionContext);

              return true;
        }
}

谢谢大家的支持。