求助silverlight+ado.net实体模型+域服务下如何用select选择器？

[一只熊猫]

我想在查询时只返回想要的列，别把所有的列都返回，就是弄不明白怎么写。请问这应该怎么弄？

            AccountsDomainContext context = new AccountsDomainContext();
            var query = from x in context.GetCompanysQuery()
                        where x.CompanyName.Equals("北京")
                        select x.CompanyId; //错误:无法将类型CompanyId隐式转换为Companys

            AccountsDomainContext context = new AccountsDomainContext();
            context.Load(context.GetCompanysQuery().Select(x=>x.CompanyId) //同样的错误
                , callback =>
                {
                    if (!callback.HasError)
                    {
                        dataGrid1.ItemsSource = callback.Entities;
                    }
                }, null);

[jv9]

请参考以下例程：

[OperationContract]
public Models.TMaster GetEntity(string masterKey)
{
    using (Models.TestDataClassesDataContext db = new Models.TestDataClassesDataContext())
    {
        db.DeferredLoadingEnabled = false;
        System.Data.Linq.DataLoadOptions option = new System.Data.Linq.DataLoadOptions();
        option.LoadWith<Models.TMaster>(m => m.TDetail);
        db.LoadOptions = option;
        return db.TMaster.FirstOrDefault(m => m.MasterKey == masterKey);
    }
}

更多请参考：

http://www.silverlightchina.net/html/tips/2010/0829/1819.html
http://www.silverlightchina.net/html/tips/2010/0418/1010.html
http://www.silverlightchina.net/html/tips/2009/1210/381.html
http://www.silverlightchina.net/html/tips/2010/0421/1038.html
http://www.silverlightchina.net/html/tips/2011/0516/7685.html

[wwwljh]

可以定义视图或是存储过程。从服务器端读到客户端。客户端得定义数据的实体与其对应。