Question

I m 试图利用实体框架代码第一弧1实施储存模式。我正在讨论的问题是编造DbContext。我有一只自动集装箱解决了国际储存地,它有一个背景提供商,仅用一个新版的DbContext和一个电线铺设。 config文档。由于林克2sql,这一部分没有问题,但欧安会似乎正在cho。我举一个例子说明问题。我删除了该法典,以简化事物,因此,你看不出任何存放方式。公正的是,在没有其他法典和课堂的情况下发生的事情。

            using (var context = new PlssContext())
            {
                var x = context.Set<User>();
                var y = x.Where(u => u.UserName == LogOnModel.UserName).FirstOrDefault();
            }

            using (var context2 = new DbContext(@"Data Source=.SQLEXPRESS;Initial Catalog=PLSS.Models.PlssContext;Integrated Security=True;MultipleActiveResultSets=True"))
            {
                var x = context2.Set<User>();
                var y = x.Where(u => u.UserName == LogOnModel.UserName).FirstOrDefault();
            }

PlsContext是我创建我的DbContext阶级的地方。存放方式没有发现任何关于PlssContext的内容。我认为,我可以做的最好办法是建立一个DbContext,说明与Sqlexpress数据库的联系,并询问这方面的数据。在新添加了PlsContext的标语之后,从该背景中发现了联系。因此,他们正在同一个软体压缩数据库上点。

第一组工程。第二点错误是:

The model backing the DbContext context has changed since the database was created. Either manually delete/update the database, or call Database.SetInitializer with an IDatabaseInitializer instance. For example, the DropCreateDatabaseIfModelChanges strategy will automatically delete and recreate the database, and optionally seed it with new data.

页: 1

var y = x.Where(u => u.UserName == LogOnModel.UserName).FirstOrDefault();

我的DbContext

namespace PLSS.Models
{
    public class PlssContext : DbContext
    {
        public DbSet<User> Users { get; set; }
        public DbSet<Corner> Corners { get; set; }
        public DbSet<Lookup_County> Lookup_County { get; set; }
        public DbSet<Lookup_Accuracy> Lookup_Accuracy { get; set; }
        public DbSet<Lookup_MonumentStatus> Lookup_MonumentStatus { get; set; }
        public DbSet<Lookup_CoordinateSystem> Lookup_CoordinateSystem { get; set; }

        public class Initializer : DropCreateDatabaseAlways<PlssContext>
        {
            protected override void Seed(PlssContext context)
            {

我用同样的错误尝试了所有的初始战略。我并不认为数据库正在变化。如果我删除,

     modelBuilder.Conventions.Remove<IncludeMetadataConvention>();

然后,错误回报是

实体类型用户不属于目前情况下的模式。

哪一种是有意义的。但是,你们如何把这一切结合起来?

Answer 1

That is correct behavior. Plain DbContext has no idea about mappings (= doesn t know any of your entities). That is the reason why you should always create derived context. Your repository doesn t know about PlssContext but you can still inject it like:

public class Repository
{
  private readonly DbContext _context;

  public Repository(DbContext context)
  {
    _context = context;
  }
  ...
}

var repository = new Repository(new PlssContext());

您可以直接使用密码。

友情链接