【EFCORE笔记】动态模型配置

使用元数据动态配置模型

动态配置表名（默认复数）

//This will singularize all table names
foreach (IMutableEntityType entityType in modelBuilder.Model.GetEntityTypes())
{
        entityType.Relational().TableName = entityType.DisplayName();
}

　　

动态修改表配置

foreach (IMutableEntityType entityType in modelBuilder.Model.GetEntityTypes())
{
        modelBuilder.Entity(entityType.Name).ToTable($"T_{ entityType.DisplayName()}");
}

　　

动态修改列配置

foreach (IMutableEntityType entityType in modelBuilder.Model.GetEntityTypes())
{
        foreach (IMutableProperty property in entityType.GetProperties()
.Where(p => p.ClrType == typeof(string)))
        {
                property.SetMaxLength(20);
        }
}

foreach (IMutableEntityType entityType in modelBuilder.Model.GetEntityTypes())
{
        foreach (IMutableProperty property in entityType.GetProperties()
.Where(p => p.ClrType == typeof(string)))
        {
                modelBuilder.Entity(entityType.Name)
.Property(property.Name)
.HasColumnName($"C_{pr operty.Name}");
        }
}

　　

配置上下文

virtual void  OnConfiguring(DbContextOptionsBuilder optionsBuilder);

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
        if (!optionsBuilder.IsConfigured)
        {

                optionsBuilder.UseSqlServer("connectionString");
        }

        base.OnConfiguring(optionsBuilder);
}

　　

配置模型

virtual void  OnModelCreating(ModelBuilder modelBuilder); 

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
        modelBuilder.Entity<Blog>()
.Property(b => b.Url)
.HasColumnName("BlogUrl");

        base.OnModelCreating(modelBuilder);
}

　　

最常规最简单的写法

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
        modelBuilder.Entity<Blog>()
.Property(b => b.Url)
.HasColumnName("BlogUrl");
        modelBuilder.Entity<Blog>()
.Property(b => b.Name).HasMaxLength(50);

        modelBuilder.Entity<Post>()
.Property(b => b.Title)
.HasMaxLength(30);
        modelBuilder.Entity<Post>()
.Property(b => b.Content)
.HasMaxLength(500);

        base.OnModelCreating(modelBuilder);
}

　　

使用表达式分离配置的写法

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
        modelBuilder.Entity<Blog>(buildAction =>
        {
                buildAction.Property(b => b.Url)
.HasColumnName("BlogUrl");
                buildAction.Property(b => b.Name)
.HasMaxLength(50);
        });

        modelBuilder.Entity<Post>(buildAction =>
        {
                buildAction.Property(b => b.Title)
.HasMaxLength(30);
                buildAction.Property(b => b.Content)
.HasMaxLength(500);
        });

        base.OnModelCreating(modelBuilder);
}

　　

使用方法分离配置的写法

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
        modelBuilder.Entity<Blog>(ConfigureBlog);

        modelBuilder.Entity<Post>(ConfigurePost);

        base.OnModelCreating(modelBuilder);
}

private void ConfigureBlog(EntityTypeBuilder<Blog> buildAction)
{
        buildAction.Property(b => b.Url).HasColumnName("BlogUrl");

        buildAction.Property(b => b.Name).HasMaxLength(50);
}

private void ConfigurePost(EntityTypeBuilder<Post> buildAction)
{
        buildAction.Property(b => b.Title).HasMaxLength(30);

        buildAction.Property(b => b.Content).HasMaxLength(500);
}

　　

使用类分离配置的写法

public class BlogConfiguration : IEntityTypeConfiguration<Blog>
{
        public void Configure(EntityTypeBuilder<Blog> builder)
        {
                builder.Property(b => b.Url).HasColumnName("BlogUrl");
                builder.Property(b => b.Name).HasMaxLength(50);
        }
}

public class PostConfiguration : IEntityTypeConfiguration<Post>
{
        public void Configure(EntityTypeBuilder<Post> builder)
        {
                builder.Property(b => b.Title).HasMaxLength(30);

                builder.Property(b => b.Content).HasMaxLength(500);
        }
}

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
        modelBuilder.ApplyConfiguration(new BlogConfiguration());

        modelBuilder.ApplyConfiguration(new PostConfiguration());

        base.OnModelCreating(modelBuilder);
}


protected override void OnModelCreating(ModelBuilder modelBuilder)
{
        modelBuilder
.ApplyConfigurationsFromAssembly(Assembly.GetExecutingAssembly());

        base.OnModelCreating(modelBuilder);
}

　　

重写DbContext 相关的方法

DbContext 提供了诸多的虚方法，可在子类中直接复写对应的方法，在方法执行前后自定义操作。

public override int SaveChanges()
{
        //TODO
        return base.SaveChanges();
}

public override EntityEntry Remove(object entity)
{
        //TODO
        return base.Remove(entity);
}