物體框架核心嵌套物件，具有selfparentId

我有一個樹表結構，這些資料來自前端。在這個樹表結構中，有關于這個問題的詳細資訊的 IssueActivity 和 IssueActivityDetail。現在我的問題是，可以將多個 IssueActivityDetail 欄位添加到此 IssueActivity 欄位。我怎樣才能在 c# ef 核心方面做到這一點？我試圖用ParentId的邏輯來做到這一點。我的物體結構如下。我沒有在 FluenApi 中添加 parentId，因為我沒有完全理解它。

我的 IssueActivity 表。

public partial class IssueActivitiy
{
public int Id { get; set; }
public int IssueId { get; set; }
public byte Type { get; set; }
public short SubActivityNo { get; set; }
public string SubActivityTitle { get; set; }
public virtual Issue Issue { get; set; }
public virtual List<IssueActivitiyDetail> IssueActivitiyDetails { get; set; }
}

我的 IssueActivityDetail 表。

public partial class IssueActivitiyDetail
{
public int Id { get; set; }
public int IssueActivityId { get; set; }
public short LineNo { get; set; }
public string Definition { get; set; }
public byte RoleId { get; set; }
public byte Medium { get; set; }
public string Explanation { get; set; }
public int? ParentId { get; set; }
public virtual IssueActivitiy IssueActivity { get; set; }
}

FluentApi 配置。

public void Configure(EntityTypeBuilder<IssueActivitiy> modelBuilder)
{
modelBuilder.ToTable("IssueActivitiy");
modelBuilder.HasKey(a => a.Id);
modelBuilder.Property(e => e.SubActivityNo).HasComment("S?ra No");
modelBuilder.Property(e => e.SubActivityTitle).HasMaxLength(256).IsUnicode(false);
modelBuilder.Property(e => e.Type).HasDefaultValueSql("((1))").HasComment("1) Temel Aktivite\r\n2) Alternatif Aktivite\r\n3) ??lem ?ptal Aktivite");
modelBuilder.HasOne(d => d.Issue).WithMany(p => p.IssueActivitiys).HasForeignKey(d => d.IssueId).OnDelete(DeleteBehavior.ClientSetNull).HasConstraintName("FK_Issue_IssueActivitiy_Id");
}
public void Configure(EntityTypeBuilder<IssueActivitiyDetail> modelBuilder)
{
modelBuilder.ToTable("IssueActivitiyDetail");
modelBuilder.Property(e => e.Definition).IsRequired().HasMaxLength(2048).IsUnicode(false).HasComment("A??klama");
modelBuilder.Property(e => e.Explanation).HasMaxLength(2048).IsUnicode(false).HasComment("A??klama");
modelBuilder.Property(e => e.IssueActivityId).HasComment("Konu Id");
modelBuilder.Property(e => e.LineNo).HasComment("S?ra No");
modelBuilder.Property(e => e.Medium).HasComment("Ortam (Excel, Mail vb.)");
modelBuilder.Property(e => e.RoleId).HasComment("Rol");
modelBuilder.Property(e => e.ParentId);
modelBuilder.HasOne(d => d.IssueActivity).WithMany(p => p.IssueActivitiyDetails).HasForeignKey(d => d.IssueActivityId).OnDelete(DeleteBehavior.ClientSetNull).HasConstraintName("FK_IssueActivitiy_IssueActivitiyDetail_");
}

Web Api 也是我嘗試接收和處理資料的地方，但我玩了很多，無法正確執行。

var vIssueActivity = issueInfo.IssueActivitiyInfos
.Select(a => new IssueActivitiy
{
Type = a.Type,
SubActivityNo = a.SubActivityNo,
SubActivityTitle = a.SubActivityTitle,
IssueActivitiyDetails = a.IssueActivitiyDetailInfos
.Select(x => new IssueActivitiyDetail
{
 
LineNo = x.LineNo,
Definition = x.Definition,
RoleId = vUser.RoleId,
Medium = x.Medium,
Explanation = x.Explanation,
IssueActivityDetail = new List<IssueActivitiyDetail> { }
}).ToList()
});

uj5u.com熱心網友回復：

您不需要將ParentId財產保留在IssueActivityDetail.

public partial class IssueActivitiy
{
    ...
    public virtual List<IssueActivitiyDetail> IssueActivitiyDetails { get; set; }
}

public partial class IssueActivitiyDetail
{
    ...
    public virtual IssueActivitiy IssueActivity { get; set; }
}

你的配置看起來沒有錯。

也許您可以Include在從 db 背景關系中獲取物體時使用。

var issueActivity = context.IssueActivities.Include(x => x.IssueActivityDetails).FirstOrDefault();

uj5u.com熱心網友回復：

您可以通過從資料庫中檢索所有條目來完成此操作。然后選擇 Root 節點，然后讓 EF Core 映射完成剩下的作業。

public class TreeNode 
{
    public bool IsRoot { get; set; }
    public int? ParentNodeId {get; set;}
    public virtual List<TreeNode> ChildNodes {get; set;}
}

public class TreeNodeRepository 
{

  public async Task<TreeNode> GetTreeStructure()
  {
      var allNodes = await _context.TreeNodes.ToListAsync();

      return allNodes.FirstOrDefault(t => t.IsRoot);
  }

}

您可能會爭辯說ParentId == null這也意味著它是一個父節點。這只是使給出的示例更加直觀。

您應該考慮性能、有多少節點會成為問題、它是否通過 web-api 公開以及迭代節點是否更有效。因此，您不必每次都將整個 Tree 加載到記憶體中，而是讓客戶端處理它。

標籤：C＃ 实体框架 实体框架核心 流出-api

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