c# - 如何使 EF 将数据插入到包含另一个表中的键值的表中？

Question

我想使用以下代码将数据添加到我的 EF 数据库：

        var applicationNames = new[] { 
            "C", 
            "E", 
            "S" };
        var testAccountNames = new[] {
            "Production",
            "Ready",
            "Beta",
            "Alpha" };
        foreach (string applicationName in applicationNames)
        {
            _uow.Applications.Add(
                new Application 
                { 
                    Name = applicationName, 
                    ModifiedDate = DateTime.Now 
                });
                foreach (string testAccountName in testAccountNames)
                {
                   new TestAccount 
                   { 
                       ApplicationID = ??
                       Name = applicationName, 
                       ModifiedDate = DateTime.Now 
                   });
                }
        }
        _uow.Commit();

这是我的课程：

public partial class Application
{
    public Application()
    {
        this.TestAccounts = new List<TestAccount>();
    }

    public int ApplicationId { get; set; }
    public string Name { get; set; }
    public byte[] RowVersion { get; set; }
    public System.DateTime ModifiedDate { get; set; }
    public virtual ICollection<TestAccount> TestAccounts { get; set; }
}

public partial class TestAccount
{
    public TestAccount()
    {
        this.Subjects = new List<Subject>();
    }

    public int TestAccountId { get; set; }
    public string Name { get; set; }
    public int ApplicationId { get; set; }
    public byte[] RowVersion { get; set; }
    public System.DateTime ModifiedDate { get; set; }
    public virtual Application Application { get; set; }
    public virtual ICollection<Subject> Subjects { get; set; }
}

这是我用于 add 方法的代码

    public virtual void Add(T entity)
    {
        DbEntityEntry dbEntityEntry = DbContext.Entry(entity);
        if (dbEntityEntry.State != EntityState.Detached)
        {
            dbEntityEntry.State = EntityState.Added;
        }
        else
        {
            DbSet.Add(entity);
        }
    }

这是映射：

    public TestAccountMap()
    {
        // Primary Key
        this.HasKey(t => t.TestAccountId);

        // Relationships
        this.HasRequired(t => t.Application)
            .WithMany(t => t.TestAccounts)
            .HasForeignKey(d => d.ApplicationId);

    }

请注意，在数据库中 ApplicationId 和 TestId 是身份数据类型。我还有一个外键，可以将 Application 表的 ApplicationID 正确链接到 TestAccount 表中的 ApplicationId。

如何使 EF 在插入数据库时​​将数据插入到 TestAccount 表中的正确 ApplicationID 中？

Answer 1

foreach (string applicationName in applicationNames)
        {
            var app = new Application 
                { 
                    Name = applicationName, 
                    ModifiedDate = DateTime.Now 
                });
            _uow.Applications.Add(app);
                foreach (string testAccountName in testAccountNames)
                {
                   new TestAccount 
                   { 
                       Application = app ,
                       Name = applicationName, 
                       ModifiedDate = DateTime.Now 
                   });
                }
        }

Answer 2

不要直接设置ID，设置引用属性，剩下的EF会整理出来，所以是这样的：

....
foreach (string applicationName in applicationNames)
    {
        _uow.Applications.Add(
            new Application 
            { 
                Name = applicationName, 
                ModifiedDate = DateTime.Now,
                TestAccounts = (from  testAccountName in testAccountNames
                                select new TestAccount
                                { 
                                   Name = testAccountName , 
                                   ModifiedDate = DateTime.Now 
                               })
            }
    }