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[英]EF Core - Unable to determine the relationship represented by navigation (One-to-Many)
[英].Net Core navigation on one-to-many relationship not working
我正在将 .Net Framework 网站转换为 .Net Core 网站。
当我放置断点并钻取公司数据时,我看到了关系,但没有看到服务器数据。 我已检查 SQL Server 并验证我确实有一个Company和一个关联的Server 。
我在 SQL Server 图中反映了一对多关系,如下所示:
本公司部分实体类如下:
public class Company
{
//
[Required(ErrorMessage = "'Company Id' is required.")]
public int CompanyId { get; set; }
[Required(ErrorMessage = "'Company Short Name' is required."), MaxLength(12, ErrorMessage = "'CompanyShortName' must be 12 or less characters.")]
public string CompanyShortName { get; set; }
[Required(ErrorMessage = "'Company Name' is required."), MaxLength(80, ErrorMessage = "'CompanyName' must be 80 or less characters.")]
public string CompanyName { get; set; }
[MaxLength(80, ErrorMessage = "'Address' must be 80 or less characters.")]
public string Address { get; set; }
...
//
public ICollection<Server> Servers { get; } = new List<Server>();
public ICollection<ApplicationUser> Users { get; } = new List<ApplicationUser>();
public ICollection<EmailTemplate> EmailTemplates { get; } = new List<EmailTemplate>();
//
}
Server 的一些实体类如下:
[Table("Servers")]
public class Server : IServer
{
//
[Required(ErrorMessage = "'Server Id' is required.")]
public int ServerId { get; set; }
[Required(ErrorMessage = "'Company Id' is required.")]
public int CompanyId { get; set; } // FK of the company that manages the server.
[Required(ErrorMessage = "'Server Short Name' is required."),
MinLength(6, ErrorMessage = "'Server Short Name' must be 6 or up to 12 characters."),
MaxLength(12, ErrorMessage = "'Server Short Name' must be 12 or less characters.")]
public string ServerShortName { get; set; } // for login
[Required(ErrorMessage = "'Server Name' is required."), MaxLength(80, ErrorMessage = "'Server Name' must be 80 or less characters.")]
public string ServerName { get; set; } // internal
...
//
public virtual Company Company { get; set; }
//
public ICollection<ApplicationUserServer> UserServers { get; }
= new List<ApplicationUserServer>();
public ICollection<NetworkLog> NetworkLogs { get; }
= new List<NetworkLog>();
public ICollection<Incident> Incidents { get; }
= new List<Incident>();
//
}
在数据库上下文中, OnModelCreating如下所示:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
...
modelBuilder.Entity<Company>((item) =>
{
item.HasKey(c => c.CompanyId);
item.HasMany(u => u.Servers).WithOne(s => s.Company).HasForeignKey(s => s.CompanyId);
item.HasIndex(c => c.CompanyShortName).IsUnique()
.HasName("Idx_Companies_ShortName");
});
//
modelBuilder.Entity<Server>((item) =>
{
item.HasKey(s => s.ServerId);
item.HasMany(u => u.UserServers).WithOne(u => u.Server).HasForeignKey(u => u.ServerId);
item.HasOne(c => c.Company).WithMany(s => s.Servers)
.HasForeignKey(s => s.CompanyId).OnDelete(DeleteBehavior.Restrict);
// index
item.HasIndex(s => s.ServerShortName).IsUnique()
.HasName("Idx_AspNetServers_ShortName");
});
...
}
.Net Core 中的许多东西与我的 .Net Framework 版本不同,所以显然我不理解某些东西。 当我收集更多信息时,我注意到其他丢失的导航数据。 此外,我的内存测试工作正常,我可以看到导航服务器数据。 这是 GitHub 上的 .Net Framework 版本:
您必须在查询结果中包含这些关系
using (var context = new BloggingContext())
{
var blogs = context.Blogs
.Include(blog => blog.Posts)
.ToList();
}
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