c# - EntityFramework 上下文中的 SaveChanges() 静默失败

Question

我正在使用数据库“向导”设置中的 Entity Framework 6.1 模型。 当我从我的上下文中创建一个业务对象，然后尝试添加附件，然后 SaveChanges() 没有任何反应。有追踪模式吗？或者我可以打开的东西，看看幕后到底发生了什么。

简单的例子:

 var fb = _context.Business.Create();
 //fb.Id exists and is an int but it is auto incr in the db
 fb.Name = ub.ACCOUNT_NAME;
 fb.ServiceManager = ub.SERVICE_MANAGER;
 fb.AccountManager = ub.ACCOUNT_MANAGER;
 fb.SalesPerson = ub.SALESPERSON;
 fb.Created = DateTime.UtcNow;
 fb.Updated = DateTime.UtcNow;
 _context.Add(fb);
 _context.SaveChanges();

Answer 1

我发现捕获 EF 错误的最佳方法是重写 SaveChange 方法，如下所示。如果你有一个中心位置来恢复日志(比如 log4net)，该函数将能够将它插入那里。

public partial class Business
{
    /// <summary>Override the SaveChange to return better error messages</summary>
    public override int SaveChanges()
    {
        try {
            return base.SaveChanges();
        }
        catch (System.Data.Entity.Validation.DbEntityValidationException ex) {
            // Retrieve the error messages as a list of strings.
            var errorMessages = ex.EntityValidationErrors
                    .SelectMany(x => x.ValidationErrors)
                    .Select(x => x.ErrorMessage);

            // Join the list to a single string.
            var fullErrorMessage = string.Join("; ", errorMessages);

            // Combine the original exception message with the new one.
            var exceptionMessage = string.Concat(ex.Message, " The validation errors are: ", fullErrorMessage);

            // Add some logging with log4net here


            // Throw a new DbEntityValidationException with the improved exception message.
            throw new System.Data.Entity.Validation.DbEntityValidationException(exceptionMessage, ex.EntityValidationErrors);

        }
    }