动态构造时如何从 IQueryable 访问列？

发布于 2024-10-15 03:19:09 字数 690 浏览 3 评论 0原文

我正在使用此处提供的 System.Linq.Data 库 - http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq- Dynamic-query-library.aspx

我有以下查询，效果很好并返回 Iqueryable

IQueryable customer =
                ctx.Customers.Where(cust => true).Select("new("Name,Address")");

但是，如何访问这些返回的列？我无法使用 lambda 表达式访问它们，如下所示：

var test = customer.Where(cust=>cust.Name == "Mike").First();

上述情况下的“cust.Name”无法解析。它不存在于“cust”的方法/属性列表中。

我假设这里出了什么问题吗？我知道我正在与匿名类型一起工作。在这种情况下我必须创建 DTO 吗？

原文

I am using the System.Linq.Data library provided here - http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx

I have the following query which works great and returns an Iqueryable

IQueryable customer =
                ctx.Customers.Where(cust => true).Select("new("Name,Address")");

However, how do I access these returned columns? I cannot access them using a lambda expression as follows:

var test = customer.Where(cust=>cust.Name == "Mike").First();

"cust.Name" in the above case cannot be resolved. It does not exist in the list of methods/properties for "cust".

Am i assuming something wrong here. I understand that I am working with an anonymous type. Do I have to create a DTO in this case?

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

滥情哥ㄟ 2024-10-22 03:19:09

对于任何 IQueryable，您都有名为 ElementType 的属性。
您可以使用它来获取属性，如下所述

IQueryable query = from t in db.Cities
               selec new 
               {
                  Id = t.Id,
                  CityName = t.Name
               };

if(query!=null)
{
    Type elementType = query.ElementType;
    foreach(PropertyInfo pi in elementType.GetProperties())
    {

    }
}

For any IQueryable you have property called ElementType.
You can use it to get the properties as explained below

IQueryable query = from t in db.Cities
               selec new 
               {
                  Id = t.Id,
                  CityName = t.Name
               };

if(query!=null)
{
    Type elementType = query.ElementType;
    foreach(PropertyInfo pi in elementType.GetProperties())
    {

    }
}

回复收藏 0 原文

慢慢从新开始 2024-10-22 03:19:09

尝试 foreach 循环：

var a = _context.SENDERS.Select(x=>new { Address=x.ADDRESS, Company=x.COMPANY });
foreach(var obj in a)
{
    Console.WriteLine(obj.Address);
    Console.WriteLine(obj.Company);
}

Try foreach loop:

var a = _context.SENDERS.Select(x=>new { Address=x.ADDRESS, Company=x.COMPANY });
foreach(var obj in a)
{
    Console.WriteLine(obj.Address);
    Console.WriteLine(obj.Company);
}

回复收藏 0 原文

~没有更多了~