控制器

Question

我有API需要验证我的用户模型。我选择了一种方法，我为创建/编辑操作创建了不同的类，以避免质量分配和划分验证以及实际模型分开。

我不知道为什么，ModelState.IsValid即使不应该返回也是如此。我做错了吗？

控制器

public HttpResponseMessage Post(UserCreate user)
{
    if (ModelState.IsValid) // It's valid even when user = null
    {
        var newUser = new User
        {
            Username = user.Username,
            Password = user.Password,
            Name = user.Name
        };
        _db.Users.Add(newUser);
        _db.SaveChanges();
        return Request.CreateResponse(HttpStatusCode.Created, new { newUser.Id, newUser.Username, newUser.Name });
    }
    return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
}

模型

public class UserCreate
{
    [Required]
    public string Username { get; set; }
    [Required]
    public string Password { get; set; }
    [Required]
    public string Name { get; set; }
}

调试证明

proof

Answer 1

ModelState.IsValid在内部检查Values.All(modelState => modelState.Errors.Count == 0)表达式。

由于没有输入，Values集合将为空，因此ModelState.IsValid将为true。

所以你需要用以下方法明确处理这个案例：

if (user != null && ModelState.IsValid)
{

}

这是一个好的还是坏的设计决定，如果你什么都不验证那就是一个不同的问题......

Answer 2

这是一个动作过滤器，用于检查空模型或无效模型。（所以你不必为每一个动作都写支票）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http.Controllers;
using System.Web.Http.Filters;

namespace Studio.Lms.TrackingServices.Filters
{
    public class ValidateViewModelAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(HttpActionContext actionContext)
        {
            if (actionContext.ActionArguments.Any(kv => kv.Value == null)) {
                actionContext.Response = actionContext.Request.CreateErrorResponse(HttpStatusCode.BadRequest, "Arguments cannot be null");
            }

            if (actionContext.ModelState.IsValid == false) {
                actionContext.Response = actionContext.Request.CreateErrorResponse(HttpStatusCode.BadRequest, actionContext.ModelState);
            }
        }
    }
}

您可以在全球注册：

config.Filters.Add(new ValidateViewModelAttribute());

或者在课程/动作上按需使用

 [ValidateViewModel]
 public class UsersController : ApiController
 { ...

Answer 3

我写了一个自定义过滤器，它不仅确保传递所有非可选对象属性，还检查模型状态是否有效：

[AttributeUsage (AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false)]
public sealed class ValidateModelAttribute : ActionFilterAttribute
{
    private static readonly ConcurrentDictionary<HttpActionDescriptor, IList<string>> NotNullParameterNames =
        new ConcurrentDictionary<HttpActionDescriptor, IList<string>> ();


    /// <summary>
    /// Occurs before the action method is invoked.
    /// </summary>
    /// <param name="actionContext">The action context.</param>
    public override void OnActionExecuting (HttpActionContext actionContext)
    {
        var not_null_parameter_names = GetNotNullParameterNames (actionContext);
        foreach (var not_null_parameter_name in not_null_parameter_names)
        {
            object value;
            if (!actionContext.ActionArguments.TryGetValue (not_null_parameter_name, out value) || value == null)
                actionContext.ModelState.AddModelError (not_null_parameter_name, "Parameter \"" + not_null_parameter_name + "\" was not specified.");
        }


        if (actionContext.ModelState.IsValid == false)
            actionContext.Response = actionContext.Request.CreateErrorResponse (HttpStatusCode.BadRequest, actionContext.ModelState);
    }


    private static IList<string> GetNotNullParameterNames (HttpActionContext actionContext)
    {
        var result = NotNullParameterNames.GetOrAdd (actionContext.ActionDescriptor,
                                                     descriptor => descriptor.GetParameters ()
                                                                             .Where (p => !p.IsOptional && p.DefaultValue == null &&
                                                                                          !p.ParameterType.IsValueType &&
                                                                                          p.ParameterType != typeof (string))
                                                                             .Select (p => p.ParameterName)
                                                                             .ToList ());

        return result;
    }
}

我把它放在所有Web API操作的全局过滤器中：

config.Filters.Add (new ValidateModelAttribute ());

Answer 4

稍微更新了asp.net核心......

[AttributeUsage(AttributeTargets.Method)]
public sealed class CheckRequiredModelAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext context)
    {
        var requiredParameters = context.ActionDescriptor.Parameters.Where(
            p => ((ControllerParameterDescriptor)p).ParameterInfo.GetCustomAttribute<RequiredModelAttribute>() != null).Select(p => p.Name);

        foreach (var argument in context.ActionArguments.Where(a => requiredParameters.Contains(a.Key, StringComparer.Ordinal)))
        {
            if (argument.Value == null)
            {
                context.ModelState.AddModelError(argument.Key, $"The argument '{argument.Key}' cannot be null.");
            }
        }

        if (!context.ModelState.IsValid)
        {
            var errors = context.ModelState.Values.SelectMany(v => v.Errors).Select(e => e.ErrorMessage);
            context.Result = new BadRequestObjectResult(errors);
            return;
        }

        base.OnActionExecuting(context);
    }
}

[AttributeUsage(AttributeTargets.Parameter)]
public sealed class RequiredModelAttribute : Attribute
{
}

services.AddMvc(options =>
{
    options.Filters.Add(typeof(CheckRequiredModelAttribute));
});

public async Task<IActionResult> CreateAsync([FromBody][RequiredModel]RequestModel request, CancellationToken cancellationToken)
{
    //...
}

Answer 5

这件事发生在我身上，就我而言，我必须将using Microsoft.Build.Framework;更改为using System.ComponentModel.DataAnnotations;（并添加参考资料）。

Answer 6

我一直在寻找解决此问题的方法，然后首先来到这里。经过一些进一步的研究，我实现了以下解决方案：

您如何使用我的解决方案？您可以在全球范围内注册：

config.Filters.Add(new ValidateModelStateAttribute());

或按需使用它

[ValidateModelState]
public class UsersController : ApiController
{...

或方法

[ValidateModelState]
public IHttpActionResult Create([Required] UserModel data)
{...

如您所见，在方法参数中已放置一个[System.ComponentModel.DataAnnotations.Required]属性。这表明该模型是必需的，不能为null。

您还可以使用自定义消息：

[ValidateModelState]
public IHttpActionResult Create([Required(ErrorMessage = "Custom message")] UserModel data)
{...

这是我的代码：

using System;
using System.Collections.Concurrent;
using System.ComponentModel.DataAnnotations;
using System.Net;
using System.Net.Http;
using System.Reflection;
using System.Web.Http.Controllers;
using System.Web.Http.Filters;

namespace your_base_namespace.Web.Http.Filters
{
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true)]
    public class ValidateModelStateAttribute : ActionFilterAttribute
    {
        private delegate void ValidateHandler(HttpActionContext actionContext);

        private static readonly ConcurrentDictionary<HttpActionBinding, ValidateHandler> _validateActionByActionBinding;

        static ValidateModelStateAttribute()
        {
            _validateActionByActionBinding = new ConcurrentDictionary<HttpActionBinding, ValidateHandler>();
        }

        public override void OnActionExecuting(HttpActionContext actionContext)
        {
            GetValidateHandler(actionContext.ActionDescriptor.ActionBinding)(actionContext);

            if (actionContext.ModelState.IsValid)
                return;

            actionContext.Response = actionContext.Request.CreateErrorResponse(HttpStatusCode.BadRequest, actionContext.ModelState);
        }

        private ValidateHandler GetValidateHandler(HttpActionBinding actionBinding)
        {
            ValidateHandler validateAction;

            if (!_validateActionByActionBinding.TryGetValue(actionBinding, out validateAction))
                _validateActionByActionBinding.TryAdd(actionBinding, validateAction = CreateValidateHandler(actionBinding));

            return validateAction;
        }

        private ValidateHandler CreateValidateHandler(HttpActionBinding actionBinding)
        {
            ValidateHandler handler = new ValidateHandler(c => { });

            var parameters = actionBinding.ParameterBindings;

            for (int i = 0; i < parameters.Length; i++)
            {
                var parameterDescriptor = (ReflectedHttpParameterDescriptor)parameters[i].Descriptor;
                var attribute = parameterDescriptor.ParameterInfo.GetCustomAttribute<RequiredAttribute>(true);

                if (attribute != null)
                    handler += CreateValidateHandler(attribute, parameterDescriptor.ParameterName);
            }

            return handler;
        }

        private static ValidateHandler CreateValidateHandler(ValidationAttribute attribute, string name)
        {            
            return CreateValidateHandler(attribute, new ValidationContext(new object()) { MemberName = name });
        }

        private static ValidateHandler CreateValidateHandler(ValidationAttribute attribute, ValidationContext context)
        {
            return new ValidateHandler(actionContext =>
            {
                object value;
                actionContext.ActionArguments.TryGetValue(context.MemberName, out value);

                var validationResult = attribute.GetValidationResult(value, context);
                if (validationResult != null)
                    actionContext.ModelState.AddModelError(context.MemberName, validationResult.ErrorMessage);
            });
        }
    }
}

Answer 7

有一个简单的解决方案可以解决您的问题

public class UserCreate
{
    [Required(AllowEmptyStrings = false)]
    public string Username { get; set; }
}

此处 AllowEmptyStrings = false 可用于验证

Answer 8

我所做的是创建Attribute以及ActionFilter和Extension Method以避免空模型。

扩展方法查找具有NotNull属性的参数，并检查它们是否为null，如果为true，则将它们实例化并设置在ActionArguments属性中。

此解决方案可在此处找到：https://gist.github.com/arielmoraes/63a39a758026b47483c405b77c3e96b9

Answer 9

尝试

services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

在startup.cs文件的ConfigureServices()

中

Answer 10

这个问题发生在我身上。我不知道为什么会这么简单，只需更改你的动作对象名称（UserCreate User）就像其他人一样（UserCreate User_create）

ModelState.IsValid即使它不应该是？

控制器

模型

调试证明

10 个答案: