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提问者：小点点

Web API验证不触发自定义模型绑定器


我正在用Web API5构建Web服务。我正在通过扩展IModelBinder接口来实现自定义模型绑定器，以将复杂类型映射为操作的参数。装订部分工作正常。但不会进行模型验证。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ModelState.isValid设置正确。

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

我应该在模型绑定器内实现验证部分。如果是，我应该如何实现？


共2个答案

匿名用户

null

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;
        }
}

谢谢你们的支持。

匿名用户

应帮助您保持模型状态:

public class PaginationModelBinder : DefaultModelBinder
{
    protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Type modelType)
    {
        if(modelType == typeof(PagingParamsVM))
        {
            var page = default(int?);
            var model = bindingContext.Model;
            var valueProvider = bindingContext.ValueProvider;
            var pageValue = valueProvider.GetValue("Page");
            var tmp = default(int);
            if(pageValue != null && int.TryParse(pageValue.AttemptedValue, out tmp))
            {
                page = tmp;
            }

            var pageSize = default(int?);
            var sizeValue = valueProvider.GetValue("PageSize");
            if(sizeValue != null && int.TryParse(sizeValue.AttemptedValue, out tmp))
            {
                pageSize = tmp;
            }
            return new PagingParamsVM { Page = page, PageSize = pageSize };
        }
        return base.CreateModel(controllerContext, bindingContext, modelType);
    }
}

使用绑定器的web api控制器可以是:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Http;
using System.Web.Mvc;

public class NewsItemController : ApiController
{
    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
        return Enumerable.Empty<NewsItemVM>();
    }
}

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