EF Core: 实体类型 ‘List‘ 未找到。确保已将实体类型添加到模型中

huangapple
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英文:

EF Core: The entity type 'List<Course>' was not found. Ensure that the entity type has been added to the model

问题

我正在尝试更新数据库中的Courses表中的列，但遇到以下错误：

未找到实体类型'List'。请确保已将实体类型添加到模型中。

基本上，我正在尝试获取复选框的状态。例如，如果一位教练被选为课程的作者，然后将教练的Id输入到Course.AuthorId中。

这是控制器中的方法：

  1. [HttpPost]
  2. [ValidateAntiForgeryToken]
  3. public async Task<IActionResult> EditInstructorCourse(int id, List<EditInstructorCourseViewModel> model)
  4. {
  5.     if (_context.Courses is null)
  6.     {
  7.         return NotFound();
  8.     }
  10.     var courses = await _context.Courses.ToListAsync();
  12.     try
  13.     {
  14.         for (int i = 0; i < model.Count; i++)
  15.         {
  16.             if (model[i].IsAuthor = true)
  17.             {
  18.                 courses[i].AuthorId = id;
  19.                 _context.Update(courses);
  20.             }
  21.             else
  22.             {
  23.                 courses[i].AuthorId = null;
  24.             }
  25.         }
  27.         _context.SaveChangesAsync();
  28.     }
  29.     catch (DbUpdateConcurrencyException)
  30.     {
  31.         throw;
  32.     }
  34.     return RedirectToAction(nameof(Index));
  35. }

这是视图模型：

  1. public class EditInstructorCourseViewModel
  2. {
  3.     public string CourseId { get; set; }
  4.     public string CourseName { get; set; }
  5.     public string CourseAuthor { get; set; }
  6.     public string CourseEditor { get; set; }
  8.     public bool IsAuthor { get; set; }
  9.     public bool IsEditor { get; set; }
  10. }

模型类：

  1. public class Instructor
  2. {
  3.     public int Id { get; set; }
  5.     [DisplayName("Instructor")]
  6.     public string InstructorName { get; set; }
  8.     [ForeignKey("AuthorId")]
  9.     [DisplayName("Author Of")]
  10.     public ICollection<Course> CoursesAuthored { get; set; } = new List<Course>();
  12.     [ForeignKey("EditorId")]
  13.     [DisplayName("Editor Of")]
  14.     public List<Course> CoursesEdited { get; set; } = new List<Course>();
  15. }
  17. public class Course
  18. {
  19.     public int Id { get; set; }
  21.     [DisplayName("Course")]
  22.     public string CourseName { get; set; }
  24.     public int? AuthorId { get; set; }
  25.     public Instructor? Author { get; set; }
  26.     public int? EditorId { get; set; }
  27.     public Instructor? Editor { get; set; }
  28. }

Fluent API：

  1. protected override void OnModelCreating(ModelBuilder modelBuilder)
  2. {
  3.     modelBuilder.Entity<Course>()
  4.         .HasOne(course => course.Editor)
  5.         .WithMany(editor => editor.CoursesEdited)
  6.         .HasForeignKey(course => course.EditorId);
  8.     modelBuilder.Entity<Course>()
  9.         .HasOne(course => course.Author)
  10.         .WithMany(editor => editor.CoursesAuthored)
  11.         .HasForeignKey(course => course.AuthorId);
  12. }

和视图部分已提供。希望这些信息对你有所帮助。

英文:

I am trying to update columns in the database for a Courses table, but get the following error:

> The entity type 'List<Course>' was not found. Ensure that the entity type has been added to the model.

Basically I'm trying to get the state of the check boxes. For example if a course is selected for an Instructor as an author of that course, then enter the instructor's Id into the Course.AuthorId

Here is the method in the controller

  1. [HttpPost]
  2. [ValidateAntiForgeryToken]
  3. public async Task&lt;IActionResult&gt; EditInstructorCourse(int id, List&lt;EditInstructorCourseViewModel&gt; model)
  4. {
  5.         if (_context.Courses is null)
  6.         {
  7.             return NotFound();
  8.         }
  10.         var courses = await _context.Courses.ToListAsync();
  12.         try
  13.         {
  14.             for (int i = 0; i &lt; model.Count; i++)
  15.             {
  16.                 if (model[i].IsAuthor = true)
  17.                 {
  18.                     courses[i].AuthorId = id;
  19.                     _context.Update(courses);
  20.                 }
  21.                 else
  22.                 {
  23.                     courses[i].AuthorId = null;
  24.                 }
  25.             }
  27.             _context.SaveChangesAsync();
  28.         }
  29.         catch (DbUpdateConcurrencyException)
  30.         {
  31.             throw;
  32.         }
  34.         return RedirectToAction(nameof(Index));
  35. }

Here is the view model

  1. public class EditInstructorCourseViewModel
  2. {
  3.     public string CourseId { get; set; }
  4.     public string CourseName { get; set; }
  5.     public string CourseAuthor { get; set; }
  6.     public string CourseEditor { get; set; }
  8.     public bool IsAuthor { get; set; }
  9.     public bool IsEditor { get; set; }
  10. }

The model classes:

  1. public class Instructor
  2. {
  3.     public int Id { get; set; }
  5.     [DisplayName(&quot;Instructor&quot;)]
  6.     public string InstructorName { get; set; }
  8.     [ForeignKey(&quot;AuthorId&quot;)]
  9.     [DisplayName(&quot;Author Of&quot;)]
  10.     public ICollection&lt;Course&gt; CoursesAuthored { get; set; } = new List&lt;Course&gt;();
  12.     [ForeignKey(&quot;EditorId&quot;)]
  13.     [DisplayName(&quot;Editor Of&quot;)]
  14.     public List&lt;Course&gt; CoursesEdited { get; set; } = new List&lt;Course&gt;();
  15. }
  17. public class Course
  18. {
  19.     public int Id { get; set; }
  21.     [DisplayName(&quot;Course&quot;)]
  22.     public string CourseName { get; set; }
  24.     public int? AuthorId { get; set; }
  25.     public Instructor? Author { get; set; }
  26.     public int? EditorId { get; set; }
  27.     public Instructor? Editor { get; set; }
  28. }

Fluent API

  1. protected override void OnModelCreating(ModelBuilder modelBuilder)
  2. {
  3.     modelBuilder.Entity&lt;Course&gt;()
  4.         .HasOne(course =&gt; course.Editor)
  5.         .WithMany(editor =&gt; editor.CoursesEdited)
  6.         .HasForeignKey(course =&gt; course.EditorId);
  8.     modelBuilder.Entity&lt;Course&gt;()
  9.         .HasOne(course =&gt; course.Author)
  10.         .WithMany(editor =&gt; editor.CoursesAuthored)
  11.         .HasForeignKey(course =&gt; course.AuthorId);
  12. }

And the view

  1. @model List&lt;OneToManyMany.Models.ViewModels.EditInstructorCourseViewModel&gt;
  3. @{
  4.     var instructorId = ViewData[&quot;InstructorId&quot;];
  5.     var instructorName = ViewData[&quot;InstructorName&quot;];
  6. }
  8. &lt;h2&gt;Edit Courses for &lt;strong&gt; @instructorName&lt;/strong&gt;&lt;/h2&gt;
  11. &lt;div class=&quot;form-group&quot;&gt;
  12.     &lt;label asp-for=&quot;@instructorName&quot; class=&quot;control-label&quot;&gt;&lt;/label&gt;
  13.     &lt;input asp-for=&quot;@instructorName&quot; class=&quot;form-control&quot; /&gt;
  14.     &lt;span asp-validation-for=&quot;@instructorName&quot; class=&quot;text-danger&quot;&gt;&lt;/span&gt;
  15. &lt;/div&gt;
  17. &lt;div&gt;
  18.     &lt;form asp-action=&quot;EditInstructorCourse&quot; method=&quot;post&quot;&gt;
  19.         &lt;div asp-validation-summary=&quot;ModelOnly&quot; class=&quot;text-danger&quot;&gt;&lt;/div&gt;
  20.         &lt;input type=&quot;hidden&quot; asp-for=&quot;@instructorId&quot; /&gt;
  21.         &lt;div class=&quot;form-group&quot;&gt;
  22.             &lt;h5&gt;Author Of&lt;/h5&gt;
  23.             @for (int i = 0; i &lt; Model.Count; i++)
  24.             {
  25.                 &lt;div class=&quot;form-check m-1&quot;&gt;
  26.                     &lt;input type=&quot;hidden&quot; asp-for=&quot;@Model[i].CourseId&quot; /&gt;
  27.                     &lt;input type=&quot;hidden&quot; asp-for=&quot;@Model[i].CourseName&quot; /&gt;
  28.                     &lt;input asp-for=&quot;@Model[i].IsAuthor&quot; class=&quot;form-check-input&quot; /&gt;
  29.                     &lt;label class=&quot;form-check-label&quot; asp-for=&quot;@Model[i].IsAuthor&quot;&gt;
  30.                         @Model[i].CourseName
  31.                     &lt;/label&gt;
  32.                 &lt;/div&gt;
  33.             }
  34.         &lt;/div&gt;
  35.         &lt;div class=&quot;form-group&quot;&gt;
  36.             &lt;h5&gt;Editor Of&lt;/h5&gt;
  37.             @for (int i = 0; i &lt; Model.Count; i++)
  38.             {
  39.                 &lt;div class=&quot;form-check m-1&quot;&gt;
  40.                     &lt;input type=&quot;hidden&quot; asp-for=&quot;@Model[i].CourseId&quot; /&gt;
  41.                     &lt;input type=&quot;hidden&quot; asp-for=&quot;@Model[i].CourseName&quot; /&gt;
  42.                     &lt;input asp-for=&quot;@Model[i].IsEditor&quot; class=&quot;form-check-input&quot; /&gt;
  43.                     &lt;label class=&quot;form-check-label&quot; asp-for=&quot;@Model[i].IsEditor&quot;&gt;
  44.                         @Model[i].CourseName
  45.                     &lt;/label&gt;
  46.                 &lt;/div&gt;
  47.             }
  48.         &lt;/div&gt;
  49.         &lt;div class=&quot;mt-4&quot;&gt;
  50.             &lt;a asp-controller=&quot;Instructors&quot; asp-action=&quot;Index&quot; asp-route-id=&quot;@instructorId&quot; class=&quot;btn btn-secondary me-2&quot;&gt;Cancel&lt;/a&gt;
  51.             &lt;button id=&quot;saveBtn&quot; type=&quot;submit&quot; class=&quot;btn btn-primary&quot;&gt;Save&lt;/button&gt;
  52.         &lt;/div&gt;
  53.     &lt;/form&gt;
  54.     &lt;hr /&gt;
  55. &lt;/div&gt;

Any help would be greatly appreciated.

答案1

得分: 1

要更新实体：您需要获取实体，更新值，然后调用SaveChangesAsync。在您的情况下，不需要调用update。只需按@ivan建议的方式将其删除。

英文:

To update the entity: you need to get the entity, update the value and call SaveChangesAsync. No need to call update in your case. Just remove it as suggested by @ivan

huangapple
  • 本文由 发表于 2023年7月17日 09:36:39
  • 转载请务必保留本文链接：https://go.coder-hub.com/76701054.html
  • c#
  • entity-framework-core

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