Question

我有实体框架代码，应该更新名为Asset的实体。出于某种原因，它没有按预期进行更新。调试以查看此问题的根本原因很困难，因为我没有看到任何例外。

问题出在存储库类中，它始终返回

资产无法更新

即使我传入有效的Book或Asset对象，也会发送

消息。

模型类

public class Asset
{
    public Guid Id { get; set; }
    public string Name { get; set; }
}

public class Book : Asset
{
    public string Isbn { get; set; }
    public string Edition { get; set; }
    public string  Publisher { get; set; }
    public virtual  User User { get; set; }
}

控制器类

[System.Web.Http.Authorize]
public async  Task<IHttpActionResult> Put([FromBody] BookViewModel model)
{
        string result = null;

        try
        {
            if (model.IsEmpty) 
                return BadRequest(ModelState);

            result = await _assetAssetRepository.Update(Mapper.Map<Book>(model));
            return Content(HttpStatusCode.Created, result);
        }
        catch (Exception ex)
        {
            return Content(HttpStatusCode.InternalServerError, result);
        }
}

存储库类：

public class AssetRepository
{
     private readonly GenAppContext _context = new GenAppContext();

     public Task<string> Update(Asset asset)
     {
         try
         {
            var updateTask = Task<string>.Factory.StartNew(() =>
            {
                if (!(asset is Book)) 
                    return "Please return correct type of asset";

                var _asset = _context.Assets.SingleOrDefault(x => x.Id == asset.Id);

                if (_asset == null) 
                    throw new ArgumentNullException(nameof(_asset));

                _asset.Name = asset.Name;
                ((Book) _asset).Edition = ((Book) asset).Edition;
                ((Book) _asset).Publisher = ((Book) asset).Publisher;
                ((Book) _asset).Isbn = ((Book) asset).Isbn;

                _context.Assets.AddOrUpdate(_asset);

                return _context.SaveChanges() > 0
                    ? "Asset has been updated successfully"
                    : "Asset could not be updated";
            });

            return updateTask;
        }
        catch (Exception ex)
        {
            return Task<string>.Factory.StartNew(() => ex.Message + " " + ex.StackTrace);
        }
    }
}

实体框架在使用Task.Factory时不更新实体

0 个答案: