c# - 在这个 ObjectSet.SelectValue 示例中， "it"来自哪里？

Question

productQuery1.SelectValue<Int32>("it.ProductID");

我怎么知道这里的“它”是什么意思？

整个示例来自 MSDN docs

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    string queryString =
        @"SELECT VALUE product FROM 
            AdventureWorksEntities.Products AS product";

    ObjectQuery<Product> productQuery1 =
        new ObjectQuery<Product>(queryString,
            context, MergeOption.NoTracking);

    ObjectQuery<Int32> productQuery2 =
        productQuery1.SelectValue<Int32>("it.ProductID");

    foreach (Int32 result in productQuery2)
    {
        Console.WriteLine("{0}", result);
    }
}

Answer 1

它更像是这个。

It's a convention in query builder methods .

In a query builder method, you refer to the current ObjectQuery command by using an alias. By default, the string "it" is the alias that represents the current command...