NHibernate Lambda 扩展 - CreateCriteria 问题

Question

我想将 NHibernate CreateCriteria 转换为 NHLambdaExtensions标准，但我遇到了不知道如何修复的错误。

NHibernate 标准如下所示:

var departments = DepartmentService
    .CreateCriteria()
    .CreateAlias( "Goals", "goal" )
    .Add( Expression.Eq( "goal.Company.Id", companyId ) )
    .Add( Expression.Eq( "goal.Program.Id", programId ) )
    .List<Business.Department>();

我尝试创建的 NHLambdaExtensions 标准如下所示:

Business.Goal goalAlias = null;
var departments = DepartmentService
    .CreateCriteria()
    .CreateAlias<Business.Goal>( g => g.Department, () => goalAlias )
    .Add<Business.Goal>( g => g.Company.Id == companyId )
    .Add<Business.Goal>( g => g.Program.Id == programId )
    .List<Business.Department>();

我收到的错误是“无法解析属性部门:Business.Department”。该错误显然与“g => g.Department”有关，原始 NHibernate 查询中没有任何类似的内容，但不存在不采用该表达式的重载。

Answer 1

Business.Goal goalAlias = null;
var departments = DepartmentService
    .CreateCriteria(typeof(Business.Department)) // need to specify the first criteria as Business.Department
        .CreateCriteria<Business.Department>(d => d.Goals, () => goalAlias)
            .Add<Business.Goal>( g => g.Company.Id == companyId )
            .Add<Business.Goal>( g => g.Program.Id == programId )
    .List<Business.Department>();

在 NHibernate Lambda Extensions (V1.0.0.0) - Documentation 中查找“创建与别名的条件关联”

编辑:

实际上，您可以更有效地将其编写为:

// no alias necessary
var departments = DepartmentService
    .CreateCriteria<Business.Department>()
        .CreateCriteria<Business.Department>(d => d.Goals)
            .Add<Business.Goal>( g => g.Company.Id == companyId )
            .Add<Business.Goal>( g => g.Program.Id == programId )
    .List<Business.Department>();