Question

我想将NHibernate CreateCriteria转换为NHLambdaExtensions条件，但我收到的错误是我不知道如何修复。

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>();

我正在尝试创建的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>();

我得到的错误是“无法解析财产部门：Business.Department”。该错误显然与“g =＆gt; g.Department”有关，并且原始NHibernate查询中没有任何内容具有相似之处，但没有任何重载都没有表达。

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“使用别名创建条件关联”

编辑：

你实际上可以更有效地写这个：

// 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>();

Answer 2

我没有使用NHLambdaExpressions（但它看起来很酷，我很快就会把它检出来），所以我只是猜测一下。你能做这样的事吗：

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

我认为这将在Goals中生成一个新标准，并通过goalAlias分配一个别名。

NHibernate Lambda扩展 - CreateCriteria问题

2 个答案: