在EF Core中创建类通过实现IEntityTypeConfiguration＜T＞接口 实现实体类的伙伴类 实现FluentApi

1 创建实体类:

 public partial class NewsCategory : IAggregationRoot
    {
        public NewsCategory() { }
        public Guid Id { get; set; }
        public string CategoryName { get; set; }
        public bool IsDel { get; set; }
        public string Code { get; set; }
    }

2.创建实体类的映射伙伴类

public class NewsCategoryMap : IEntityTypeConfiguration<NewsCategory>
    {
        public void Configure(EntityTypeBuilder<NewsCategory> builder)
        {
            builder.ToTable("NewsCategory");
        }
    }

3.在上下文中 重写 OnModelCreating方法 将伙伴类的应用上

 public class NewsEFCoreContext:DbContext,INewsContext
    {
       
        public DbSet<NewsCategory> Categories { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            //先直接写连接字符串，生成数据库。后续再在配置文件中配置，并使用到此处
            optionsBuilder.UseSqlServer("Server=localhost;Database=wehope;User ID=sa;Password=0");
            //optionsBuilder.UseSqlServer(AppSetting.GetAppSetting("DealerContext"));
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.ApplyConfiguration<NewsCategory>(new NewsCategoryMap());
            base.OnModelCreating(modelBuilder); 
        }
    }

完成。

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EF Core如何使用IEntityTypeConfiguration<TEntity>

首先构建IEntityTypeConfiguration<T>抽象泛型继承类KopEntityTypeConfiguration

public abstract class KopEntityTypeConfiguration<T> : IEntityTypeConfiguration<T>

创建基于 KopEntityTypeConfiguration类的 GroupMappingMap

public class GroupMappingMap : KopEntityTypeConfiguration<GroupMapping>

实现 KopEntityTypeConfiguration类的 Configure函数

public override void Configure(EntityTypeBuilder<GroupMapping> builder)

在数据上下文 ApplicationDbContext : DbContext实现的 OnModelCreating函数中，使用ModelBuilder实现应用设置

OnModelCreating函数的全部代码是

protected override void OnModelCreating(ModelBuilder builder)
        {
            builder.ApplyConfiguration(new GroupMappingMap());//应用设置
            base.OnModelCreating(builder);
            // Customize the ASP.NET Identity model and override the defaults if needed.
            // For example, you can rename the ASP.NET Identity table names and more.
            // Add your customizations after calling base.OnModelCreating(builder);
        }