如何从 ASP.Net MVC modelState 获取所有错误？

Question

我想在不知道键值的情况下从 modelState 中获取所有错误消息。循环获取 ModelState 包含的所有错误消息。

我该怎么做？

Answer 1

使用 LINQ：

IEnumerable<ModelError> allErrors = ModelState.Values.SelectMany(v => v.Errors);

Answer 2

foreach (ModelState modelState in ViewData.ModelState.Values) {
    foreach (ModelError error in modelState.Errors) {
        DoSomethingWith(error);
    }
}

另请参阅如何做我得到了 ASP.NET MVC 中模型状态错误的集合？。

Answer 3

在 LINQ 版本的基础上，如果要将所有错误消息连接到一个字符串中：

string messages = string.Join("; ", ModelState.Values
                                        .SelectMany(x => x.Errors)
                                        .Select(x => x.ErrorMessage));

Answer 4

我可以使用一点 LINQ 来完成此操作，

public static List<string> GetErrorListFromModelState
                                              (ModelStateDictionary modelState)
{
      var query = from state in modelState.Values
                  from error in state.Errors
                  select error.ErrorMessage;

      var errorList = query.ToList();
      return errorList;
}

上面的方法返回验证错误列表。

进一步阅读：

如何从 ASP.NET MVC 中的 ModelState 读取所有错误

Answer 5

在调试过程中，我发现在每个页面的底部放置一个表格来显示所有 ModelState 错误很有用。

<table class="model-state">
    @foreach (var item in ViewContext.ViewData.ModelState) 
    {
        if (item.Value.Errors.Any())
        { 
        <tr>
            <td><b>@item.Key</b></td>
            <td>@((item.Value == null || item.Value.Value == null) ? "<null>" : item.Value.Value.RawValue)</td>
            <td>@(string.Join("; ", item.Value.Errors.Select(x => x.ErrorMessage)))</td>
        </tr>
        }
    }
</table>

<style>
    table.model-state
    {
        border-color: #600;
        border-width: 0 0 1px 1px;
        border-style: solid;
        border-collapse: collapse;
        font-size: .8em;
        font-family: arial;
    }

    table.model-state td
    {
        border-color: #600;
        border-width: 1px 1px 0 0;
        border-style: solid;
        margin: 0;
        padding: .25em .75em;
        background-color: #FFC;
    }
 </style>

Answer 6

正如我发现遵循到目前为止给出的答案中的建议，您可以在没有设置错误消息的情况下发生异常，因此要捕获所有问题，您确实需要同时获取 ErrorMessage 和 Exception。

String messages = String.Join(Environment.NewLine, ModelState.Values.SelectMany(v => v.Errors)
                                                           .Select( v => v.ErrorMessage + " " + v.Exception));

或作为扩展方法

public static IEnumerable<String> GetErrors(this ModelStateDictionary modelState)
{
      return modelState.Values.SelectMany(v => v.Errors)
                              .Select( v => v.ErrorMessage + " " + v.Exception).ToList();

}

Answer 7

如果有人想要返回模型属性的名称以将错误消息绑定到强类型视图中。

List<ErrorResult> Errors = new List<ErrorResult>();
foreach (KeyValuePair<string, ModelState> modelStateDD in ViewData.ModelState)
{
    string key = modelStateDD.Key;
    ModelState modelState = modelStateDD.Value;

    foreach (ModelError error in modelState.Errors)
    {
        ErrorResult er = new ErrorResult();
        er.ErrorMessage = error.ErrorMessage;
        er.Field = key;
        Errors.Add(er);
    }
}

这样，您实际上可以将错误与引发错误的字段联系起来。

Answer 8

此代码片段也很有用，它为您提供一个包含错误消息的列表。

var error = ModelState.Values.SelectMany(x => x.Errors.Select(c => c.ErrorMessage)).ToList();

Answer 9

仅输出错误消息本身对我来说还不够，但这确实解决了问题。

var modelQuery = (from kvp in ModelState
                  let field = kvp.Key
                  let state = kvp.Value
                  where state.Errors.Count > 0
                  let val = state.Value?.AttemptedValue ?? "[NULL]"

                  let errors = string.Join(";", state.Errors.Select(err => err.ErrorMessage))
                  select string.Format("{0}:[{1}] (ERRORS: {2})", field, val, errors));

Trace.WriteLine(string.Join(Environment.NewLine, modelQuery));

Answer 10

任何人都在寻找 asp.net core 3.1。答案包括键（字段名称）。大多数其他答案仅包含错误。

我发现这就是 [ApiController] 返回的

 Dictionary<string, List<string>> errors = new Dictionary<string, List<string>>();

                foreach (KeyValuePair<string, ModelStateEntry> kvp in ViewData.ModelState)
                {
                    string key = kvp.Key;
                    ModelStateEntry entry = kvp.Value;

                    if (entry.Errors.Count > 0)
                    {
                        List<string> errorList = new List<string>();
                        foreach (ModelError error in entry.Errors)
                        {
                            errorList.Add(error.ErrorMessage);
                        }

                        errors[key] = errorList;
                    }
                }

                return  new JsonResult(new {Errors = errors});

Answer 11

为了以防万一有人需要它，我在我的项目中创建并使用以下静态类

使用示例：

if (!ModelState.IsValid)
{
    var errors = ModelState.GetModelErrors();
    return Json(new { errors });
}

用途：

using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web.Mvc;
using WebGrease.Css.Extensions;

类：

public static class ModelStateErrorHandler
{
    /// <summary>
    /// Returns a Key/Value pair with all the errors in the model
    /// according to the data annotation properties.
    /// </summary>
    /// <param name="errDictionary"></param>
    /// <returns>
    /// Key: Name of the property
    /// Value: The error message returned from data annotation
    /// </returns>
    public static Dictionary<string, string> GetModelErrors(this ModelStateDictionary errDictionary)
    {
        var errors = new Dictionary<string, string>();
        errDictionary.Where(k => k.Value.Errors.Count > 0).ForEach(i =>
        {
            var er = string.Join(", ", i.Value.Errors.Select(e => e.ErrorMessage).ToArray());
            errors.Add(i.Key, er);
        });
        return errors;
    }

    public static string StringifyModelErrors(this ModelStateDictionary errDictionary)
    {
        var errorsBuilder = new StringBuilder();
        var errors = errDictionary.GetModelErrors();
        errors.ForEach(key => errorsBuilder.AppendFormat("{0}: {1} -", key.Key,key.Value));
        return errorsBuilder.ToString();
    }
}

Answer 12

<div class="text-danger" style="direction:rtl" asp-validation-summary="All"></div>

只需使用 asp-validation-summary 标签帮助程序

Answer 13

这也有效：

var query = from state in ModelState.Values
    from error in state.Errors
    select error.ErrorMessage;
var errors = query.ToArray(); // ToList() and so on...

Answer 14

对于将错误消息数组传递给 View 很有用，也许可以通过 Json：

messageArray = this.ViewData.ModelState.Values.SelectMany(modelState => modelState.Errors, (modelState, error) => error.ErrorMessage).ToArray();

Answer 15

这是对@Dunc 答案的扩展。请参阅 xml 文档注释

// ReSharper disable CheckNamespace
using System.Linq;
using System.Web.Mvc;


public static class Debugg
{
    /// <summary>
    /// This class is for debugging ModelState errors either in the quick watch 
    /// window or the immediate window.
    /// When the model state contains dozens and dozens of properties, 
    /// it is impossible to inspect why a model state is invalid.
    /// This method will pull up the errors
    /// </summary>
    /// <param name="modelState">modelState</param>
    /// <returns></returns>
    public static ModelError[]  It(ModelStateDictionary modelState)
    {
        var errors = modelState.Values.SelectMany(x => x.Errors).ToArray();
        return errors;            
    }
}

Answer 16

对于 AJAX 请求更好的解决方案：

    public IActionResult Demo(DemoInfo formData)
    {
        if (!ModelState.IsValid)
        {
            IEnumerable<object> formErrors = ModelState.Select((s) => new { 
                fieldName = s.Key, 
                fieldValue = s.Value.RawValue,
                fieldMessage = s.Value.Errors.FirstOrDefault()?.ErrorMessage
            });
            return Json(new { formValid = 0, formErrors });
        }
        return Json(new { formValid = 1 });
    }

响应格式将是：

{"formValid":0,
 "formErrors":[{
     "fieldName":"name of field from object",
     "fieldValue":"value from browser",
     "fieldMessage":null /*Error message from model annotations if field is valid the value will be null */
 }]
}

有关 Func<> 的更多详细信息检查此页面： Func< TSource,Int32,TResult>)

Answer 17

此外，ModelState.Values.ErrorMessage 可能为空，但 ModelState.Values.Exception.Message 可能指示错误。

Answer 18

获取带有字段名称和错误消息的错误

var errors = new List<ErrorDto>();
foreach (KeyValuePair<string, ModelStateEntry> kvp in context.ModelState)
{
    if (kvp.Value.Errors.Count > 0)
    {
        errors.Add(new ErrorDto()
        {
            FieldName = kvp.Key,
            ErrorMessage = string.Join(",", kvp.Value.Errors.Select(v => v.ErrorMessage))
        });
    }
}

错误模型

    public class ErrorDto
    {
        public string FieldName { get; set; }
        public string ErrorMessage { get; set; }
    }

Answer 19

var x = new Dictionary<string,string>();
for (var b = 0; b < ViewData.ModelState.Values.Count(); b++)
{
    if (ViewData.ModelState.Values.ElementAt(b).Errors.Count() > 0)
        x.Add(ViewData.ModelState.Keys.ElementAt(b), String.Join(",", ViewData
            .ModelState.Values.ElementAt(b).Errors.Select(c => c.ErrorMessage)));
}

Answer 20

使用字段名称..

 if (!this.ModelState.IsValid)
 {
     foreach (var modelState in this.ModelState)
     { 
         foreach (var error in modelState.Value.Errors)
         {
             rModel.AddError(error.ErrorMessage, ErrorType.Error, modelState.Key);
         }
     }

     rModel.Message = "Invalid Data";
     return false;
 }

Answer 21

在您的实现中，您缺少静态类，这应该是。

if (!ModelState.IsValid)
{
    var errors =  ModelStateErrorHandler.GetModelErrors(this.ModelState);
    return Json(new { errors });
}

而是

if (!ModelState.IsValid)
{
    var errors = ModelState.GetModelErrors();
    return Json(new { errors });
}

Answer 22

var result = string.Join(',',ModelState.Values.SelectMany(v => v.Errors).Select(a=>a.ErrorMessage));