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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
我正在將 .Net Framework 網站轉換為 .Net Core 網站。
當我放置斷點並鑽取公司數據時,我看到了關系,但沒有看到服務器數據。 我已檢查 SQL Server 並驗證我確實有一個Company和一個關聯的Server 。
我在 SQL Server 圖中反映了一對多關系,如下所示:
本公司部分實體類如下:
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 的一些實體類如下:
[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>();
//
}
在數據庫上下文中, 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 中的許多東西與我的 .Net Framework 版本不同,所以顯然我不理解某些東西。 當我收集更多信息時,我注意到其他丟失的導航數據。 此外,我的內存測試工作正常,我可以看到導航服務器數據。 這是 GitHub 上的 .Net Framework 版本:
您必須在查詢結果中包含這些關系
using (var context = new BloggingContext())
{
var blogs = context.Blogs
.Include(blog => blog.Posts)
.ToList();
}
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