如何从 Linq 查询中提取结果？

发布于 2024-09-16 09:24:31 字数 612 浏览 8 评论 0原文

class Program
{
    static void Main(string[] args)
    {
        MyDatabaseEntities entities = new MyDatabaseEntities();

        var result = from c in entities.Categories
                        join p in entities.Products on c.ID equals p.IDCategory
                        group p by c.Name into g
                        select new
                        {
                            Name = g.Key,
                            Count = g.Count()
                        };

        Console.WriteLine(result.ToString());
        Console.ReadLine();
    }
}

如何从结果集中提取值以便使用它们？

原文

class Program
{
    static void Main(string[] args)
    {
        MyDatabaseEntities entities = new MyDatabaseEntities();

        var result = from c in entities.Categories
                        join p in entities.Products on c.ID equals p.IDCategory
                        group p by c.Name into g
                        select new
                        {
                            Name = g.Key,
                            Count = g.Count()
                        };

        Console.WriteLine(result.ToString());
        Console.ReadLine();
    }
}

How can I extract the values from ths result set so I can work with them?

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甜味拾荒者 2024-09-23 09:24:31

foreach (var item in result)
{
    var name = item.Name;
    var count = item.Count;
    ...
}

这只适用于 LINQ 查询所在的同一方法，因为编译器只会知道 LINQ 中使用的匿名对象类型 (new { }) 中哪些属性可用。选择。

如果将 LINQ 查询返回到调用方法，并且希望以上面所示的方式访问它，则必须定义显式类型并在 LINQ 查询中使用它：

class NameCountType
{
    public string Name { get; set; }
    public int Count { get; set; }
}

...

return from ... in ...
       ...
       select new NameCountType
              {
                  Name = ...,
                  Count = ...,
              };

foreach (var item in result)
{
    var name = item.Name;
    var count = item.Count;
    ...
}

This will only work inside the same method where the LINQ query is located, since the compiler will only then know which properties are available in the anonymous object type (new { }) used in your LINQ select.

If you return a LINQ query to a calling method, and you want to access it in the way shown above, you'd have to define an explicit type and use it in your LINQ query:

class NameCountType
{
    public string Name { get; set; }
    public int Count { get; set; }
}

...

return from ... in ...
       ...
       select new NameCountType
              {
                  Name = ...,
                  Count = ...,
              };

回复收藏 0 原文

落墨 2024-09-23 09:24:31

例如：

foreach (var x in result)
{
   Console.WriteLine(x.c.Name);
}

For example:

foreach (var x in result)
{
   Console.WriteLine(x.c.Name);
}

回复收藏 0 原文

书信已泛黄 2024-09-23 09:24:31

 var results = (from myRow in ds.Tables[0].AsEnumerable()
                  where myRow.Field<String>("UserName") == "XXX"
                  select myRow).Distinct();
 foreach (DataRow dr in results)
    UserList += " , "+dr[0].ToString();

 var results = (from myRow in ds.Tables[0].AsEnumerable()
                  where myRow.Field<String>("UserName") == "XXX"
                  select myRow).Distinct();
 foreach (DataRow dr in results)
    UserList += " , "+dr[0].ToString();

回复收藏 0 原文

~没有更多了~