无法在 asp.net mvc System.Data.Entity.Validation.DbEntityValidationException 中的数据库优先方法中应用验证：

Question

我制作了一个小型 mvc 应用程序，并没有尝试对其实施验证。为此，我尝试使用本教程

http://www.tutorialsteacher.com/mvc/implement-validation-in-asp.net-mvc

我做了完全正确的事情，但出现错误

我的代码如下

型号Class

namespace Bittu2
{
    using System;
    using System.Collections.Generic;
    using System.ComponentModel.DataAnnotations;

    public partial class student1
    {
        public int StudentId { get; set; }
        [Required]
        [StringLength(30)]
        public string Name { get; set; }
        public string Branch { get; set; }
        [Display(Name = "Mobile Number:")]
       [Required(ErrorMessage = "Mobile Number is required.")]
        [RegularExpression(@"^([0-9]{10})$", ErrorMessage = "Invalid Mobile Number.")]
        public Nullable<int> Mobile { get; set; }
    }
}

create Home Controller

中的操作方法

private StudentDemoEntities studentDemoEntities = new StudentDemoEntities();

        public ActionResult Index()
        {
            var s = from student1 in studentDemoEntities.student1 select student1;
            return View(s);
        }

        [HttpPost]
        public ActionResult Create(String Name, String Branch, int Mobile)
        {
            student1 stud = new student1();
            stud.Name = Name;
            stud.Branch = Branch;
            stud.Mobile = Mobile;


                if(ModelState.IsValid)
                {
                    studentDemoEntities.student1.Add(stud);
                    studentDemoEntities.SaveChanges();  //getting exception here. System.Data.Entity.Validation.DbEntityValidationException: 'Validation failed for one or more entities. 

                    return RedirectToAction("Index");
                }
               return View();


        }

我的 create 观点

model Bittu2.student1

@{
    Layout = null;
}

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Create</title>
</head>
<body>
    @using (Html.BeginForm("Create", "Home"))
    {
        <table>
            <tr>
                 <td>
                     @Html.ValidationSummary(true, "", new { @class = "text-danger" })
                 </td></tr>
            <tr>
                <td>
                    @Html.LabelFor(model => model.Name)

                </td>
                <td>
                    @Html.TextBoxFor(model => model.Name)
                    @Html.ValidationMessageFor(model => model.Name, "", new { @class = "text-danger" })
                </td>
            </tr>
            <tr>
                <td>
                    @Html.LabelFor(model => model.Branch)

                </td>
                <td>
                    @Html.TextBoxFor(model => model.Branch)
                    @Html.ValidationMessageFor(model => model.Branch, "", new { @class = "text-danger" })
                </td>
            </tr>
            <tr>
                <td>
                    @Html.LabelFor(model => model.Mobile)
                    @Html.ValidationMessageFor(model => model.Mobile, "", new { @class = "text-danger" })
                </td>
                <td>

 @Html.TextBoxFor(model => model.Mobile)
                @Html.ValidationMessageFor(model => model.Mobile, "", new { @class = "text-danger" })
                </td>
            </tr>
        </table>
        <input type="submit" value="Create" />
    }

    <p>

    </p>
    @Html.ActionLink("Back to List", "Index")


</body>
</html>

如果输入错误，我应该会在视图本身上收到消息，但我不明白哪里出了问题。

Answer 1

您应该将模型传递给创建操作，而不是传递多个字符串。将 student1 class 传递给 Create 操作，然后调用 ModelState.IsValid 检查模型是否有效。

public ActionResult Create(student1 student)
{
    if(ModelState.IsValid)
    {
        studentDemoEntities.student1.Add(student);
        studentDemoEntities.SaveChanges()

        return RedirectToAction("Index");
    }

    return View(student);
}

您还可以在调用 SaveChanges 时检查哪个属性无效：

if(ModelState.IsValid)
{
    studentDemoEntities.student1.Add(stud);
    try
    {
        return studentDemoEntities.SaveChanges();
        return RedirectToAction("Index");
    }
    catch (DbEntityValidationException dbEx)
    {
        foreach (var validationErrors in dbEx.EntityValidationErrors)
        {
            foreach (var validationError in validationErrors.ValidationErrors)
            {
                Debug.WriteLine("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage);
            }
        }
        return Index(student);
    }
}

无法在 asp.net mvc System.Data.Entity.Validation.DbEntityValidationException 中的数据库优先方法中应用验证：

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