多数情况下 NHibernate 使用配置文件进行配置， 但是我们也可以使用代码进行配置， 步骤如下：

1、 创建一个 Configuration

using Nhibernate.cfg;

var config = new Configuration()

    .SetProperty("connection.provider", "NHibernate.Connection.DriverConnectionProvider")

    .SetProperty("connection.driver_class", "NHibernate.Driver.SqlClientDriver")

    .SetProperty("dialect", "NHibernate.Dialect.MsSql2005Dialect")

    .SetProperty("proxyfactory.factory_class", "NHibernate.Bytecode.DefaultProxyFactoryFactory, NHibernate")

    .SetProperty("format_sql", "true")

    .SetProperty("show_sql", "true")

    .SetProperty("connection.connection_string", connectionString);

2、 添加映射

using NHibernate.Mapping.ByCode;

var mapper = new ModelMapper();

mapper.Class<Category>(cm => {

   cm.Schema("dbo");

   cm.Table("Categories");

   cm.Id(cat => cat.CategoryID, map => {

      map.Column("CategoryID");

      map.Generator(Generators.Native);

   });

   cm.Property(cat => cat.CategoryName, map => {

      map.Column("CategoryName");

      map.Length(100);

   });

   cm.Property(cat => cat.Description, map => {

      map.Column("Description");

      map.Length(200);

   });

});

3、 添加映射至 Configuration

var mappingDocument = mapper.CompileMappingForAllExplicitlyAddedEntities();

config.AddMapping(mappingDocument);