小编Dan*_*elC的帖子

当我尝试添加评论时,出现以下错误:

ObjectDisposedException:无法访问已处置的对象.

当代码运行第二行时:

m_context.Comments.Add(comment);
m_context.SaveChanges();

为什么要处理上下文？如果将TryAddComment方法移动到控制器中,它不会提前调用Dispose.

这是我的Controller和Repository类的样子(简化).

CommentsController.cs:

public class CommentsController : Controller
{

    private ICommentRepository m_commentRepository;

    public CommentsController(ICommentRepository commentRepository)
    {
        m_commentRepository = commentRepository;
    }

    // POST: api/Comments
    [HttpPost]
    public async Task<IActionResult> PostComment([FromBody] CommentAddViewModel commentVM)
    {
        Comment comment = new Comment
        {
            ApplicationUserId = User.GetUserId(),
            PostId = commentVM.PostId,
            Text = commentVM.Text
        };

        bool didAdd = m_commentRepository.TryAddComment(comment);

        if (!didAdd)
        {
            return new HttpStatusCodeResult(StatusCodes.Status409Conflict);
        }

        return CreatedAtRoute("GetComment", new { id = comment.CommentId }, comment);
    }

}

CommentRepository.cs:

public class CommentRepository : ICommentRepository, …

你会如何播种用户？我在这里关注他们的文档,但他们只展示了如何为ApplicationDbContext直接插入的数据设定种子.

在帐户控制器中,UserManager通过DI创建.如何在Seed方法中实例化UserManager？

 public class SeedData
{
    public static void Initialize(IServiceProvider serviceProvider)
    {
        var context = serviceProvider.GetService<ApplicationDbContext>();
        var userManager = serviceProvider.GetService<UserManager<ApplicationUser>>();

然后在Configure方法的Startup.cs中:

SeedData.Initialize(app.ApplicationServices);

这是我的模特:

public class Post
{

    [Key]
    public int PostId { get; set; }

    [Required]
    [MaxLength(140)]
    public string Title { get; set; }

    [Required]
    public string ApplicationUserId { get; set; }

    public ApplicationUser ApplicationUser { get; set; }
    public ICollection<Comment> Comments { get; set; }
}

public class Comment
{
    [Key]
    public int CommentId { get; set; }

    [Required]
    [StringLength(1000)]
    public string Text { get; set; }

    [Required]
    public int PostId { get; set; }

    [Required]
    public string ApplicationUserId { get; …