Syntax for linq query to List<string>

问题

I am trying to do something like this...

public static List<string> GetAttachmentKeyList()
{
    DataClassesDataContext dc = new DataClassesDataContext();

    List<string> list = from a in dc.Attachments
        select a.Att_Key.ToString().ToList();

    return list;
}

Visual Studio is saying...

Cannot implicitly convert type 'System.Linq.IQueryable>' to 'System.Collections.Generic.List'. An explicit conversion exists (are you missing a cast?)

What is the proper syntax???

回答1:

Give this a try

public static List<string> GetAttachmentKeyList()
{
    DataClassesDataContext dc = new DataClassesDataContext();

    List<string> list = ( from a in dc.Attachments
                          select a.Att_Key.ToString() ).ToList();

    return list;
}

回答2:

try this,

public static List<string> GetAttachmentKeyList()
{
    DataClassesDataContext dc = new DataClassesDataContext();

    return dc.Attachments.Select(a=>a.Att_Key).ToList();
}

回答3:

I guess it would something like below.

       List<string> list = (from a in dc.Attachments
                             select a.Att_Key.ToString()).ToList<string>();

Hope this helps!!

来源：https://stackoverflow.com/questions/7488980/syntax-for-linq-query-to-liststring