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：
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);
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);
});
});
var mappingDocument = mapper.CompileMappingForAllExplicitlyAddedEntities();
config.AddMapping(mappingDocument);