ASP.NET 样板 - 实体任务需要主键

Question

Im just New to C# and Currently I am trying to learn ASP.NET Single Web Page Application.

I'm currently trying to This Tutorial that is provided by ASP.NET Boilerplate, But I am having issues when I am trying to run Add-Migration "Initial"

Which says: "The entity type 'Task' requires a primary key to be defined. If you intended to use a keyless entity type, call 'HasNoKey' in 'OnModelCreating'. For more information on keyless entity types, see https://go.microsoft.com/fwlink/?linkid=2141943."

This is my Tasks.cs

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using Abp.Domain.Entities;
using Abp.Domain.Entities.Auditing;
using Abp.Timing;

namespace Acme.SimpleTaskApp.Tasks
{
    [Table("AppTasks")]
    public class Task : Entity, IHasCreationTime
    {
        public const int MaxTitleLength = 256;
        public const int MaxDescriptionLength = 64 * 1024; //64KB

        [Required]
        [StringLength(MaxTitleLength)]
        public string Title { get; set; }

        [StringLength(MaxDescriptionLength)]
        public string Description { get; set; }

        public DateTime CreationTime { get; set; }

        public TaskState State { get; set; }

        public Task()
        {
            CreationTime = Clock.Now;
            State = TaskState.Open;
        }

        public Task(string title, string description = null)
            : this()
        {
            Title = title;
            Description = description;
        }
    }

    public enum TaskState : byte
    {
        Open = 0,
        Completed = 1
    }
}

This is my SimpleTaskAppDbContext.cs

using Abp.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;
using System.Threading.Tasks;

namespace Acme.SimpleTaskApp.EntityFrameworkCore
{
    public class SimpleTaskAppDbContext : AbpDbContext
    {
        //Add DbSet properties for your entities...
        public DbSet<Task> Tasks { get; set; }

        public SimpleTaskAppDbContext(DbContextOptions<SimpleTaskAppDbContext> options) 
            : base(options)
        {

        }
    }
}

I don't know what else am I missing, I tried different tutorials that I can explore with CRUD while using asp.net boilerplate.

Answer 1

Your Entity is missing a Primary Key . If you add this to your Entity it should work.

[Key]
public int Id { get; set; }

Further Information https://docs.microsoft.com/en-us/ef/core/modeling/keys?tabs=data-annotations