外键定义为数据注释但仍返回 null

Question

我试图在 Blazor 页面中加入 tables，就像我以前在 Laravel Eloquent 中所做的那样，但不知何故无法用不同的方法解决FK 关系的数据类型，但现在我已经使数据类型相同，然后使用数据注释来定义外部，但属性仍然没有我提到的 table 模型的行。

我的代码 tblEmployees -

public partial class TblEmployee
{
    public TblEmployee()
    {
        Employeefrcs = new HashSet<Employeefrc>();
        TblEmployeeDesignations = new HashSet<TblEmployeeDesignation>();
    }

    public string EmployeeCode { get; set; }
    public string DepartmentCode { get; set; }

    // ... irrelevant properties ...

    [ForeignKey("Designation_Code")]
    public TblDesignation Designation { get; set; }

    public virtual TblDepartment DepartmentCodeNavigation { get; set; }
    public virtual ICollection<Employeefrc> Employeefrcs { get; set; }
    public virtual ICollection<TblEmployeeDesignation> TblEmployeeDesignations { get; set; }
}

和我的 tblDesignations -

代码

public partial class TblDesignation
{
    public TblDesignation()
    {
        TblEmployeeDesignations = new HashSet<TblEmployeeDesignation>();
        TblTeacherWorkLoads = new HashSet<TblTeacherWorkLoad>();
    }

    public int DesignationCode { get; set; }

    // ... irrelevant properties ...    

    public IEnumerable<TblEmployee> TblEmployees { get; set; }
    public virtual ICollection<TblEmployeeDesignation> TblEmployeeDesignations { get; set; }
    public virtual ICollection<TblTeacherWorkLoad> TblTeacherWorkLoads { get; set; }
}

和我的模型检索代码 -

<table class="table">
    <thead class="thead-dark">
    <tr>
        <th scope="col">#</th>
        <th scope="col">Name</th>
        <th scope="col">Cnic</th>
        <th scope="col">Phone</th>
        <th scope="col">Designation</th>
    </tr>
    </thead>
    <tbody>
    @{int i = 1}
    @foreach (var employee in employees ?? new List<TblEmployee>())
    {
        <tr>
            <th scope="row">@i</th>
            <td>@employee.EmployeeName</td>
            <td>@employee.CnicNo</td>
            <td>@employee.CellNo</td>
            <td>@(employee.Designation?.DesignationName ?? "Nandla")</td>
            @{i++}
        </tr>
    }
    </tbody>
</table>

我的模型构建器具有以下配置 -

modelBuilder.Entity<TblEmployee>(entity =>
{
    entity.HasKey(e => e.EmployeeCode).HasName("PK_dbo.tblEmployees");
    entity.ToTable("tblEmployees");
    entity.HasIndex(e => e.DepartmentCode, "IX_Department_Code");
    
    // ... irrelevant properties configuration ...  

    entity.HasOne(d => d.DepartmentCodeNavigation)
        .WithMany(p => p.TblEmployees)
        .HasForeignKey(d => d.DepartmentCode)
        .HasConstraintName("FK_dbo.tblEmployees_dbo.tblDepartment_Department_Code");
});

我在模型生成器中的 tbldesignation 是 -

modelBuilder.Entity<TblDesignation>(entity =>
{
    entity.HasKey(e => e.DesignationCode).HasName("PK_dbo.tblDesignations");
    entity.ToTable("tblDesignations");
    
    // ... irrelevant properties configuration ...  
});

Answer 1

只有 DataAnnotations。为简洁起见删除了其他属性。

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

public partial class TblEmployee
{
    public int DesignationCode { get; set; }

    [ForeignKey(nameof(DesignationCode))]
    public TblDesignation Designation { get; set; }
}

public partial class TblDesignation
{
    [Key]
    public int DesignationCode { get; set; }

    [InverseProperty(nameof(TblEmployee.Designation))]
    public IEnumerable<TblEmployee> TblEmployees { get; set; }
}

外键定义为数据注释但仍返回 null

Foreign key is defined as data annotation but still returning null

c#

entity-framework

entity-framework-core

blazor

blazor-server-side