Linq循环DataTable,使用匿名对象取出需要的列

var g_id = context.Request["g_id"];
DataTable dt = new DataTable();
var sql = @"select a.g_name
,c.cl_name
,c.cl_type
,c.cl_hidden
,c.grid_inner_order
,c.editor
,c.sum_able
,q.f_name
,q.f_type
from tbl_grid a
--列
left join tbl_grid_column_mapping b
on a.g_id=b.g_id
LEFT JOIN tbl_column c
on c.cl_id=b.cl_id
--filed
left join tbl_column_field_mapping  w
on w.cl_id=b.cl_id
left join tbl_field q
on q.f_id= w.f_id
where a.g_id='" + g_id+"'";
try
{
dt = dataprovider.FillDataTable(sql, CommandType.Text);
string grid_name = dt.Rows[0]["g_name"].ToString();
var column = dt.AsEnumerable().Select(n => new
{
key = n.Field<string>("f_name"),
value = n.Field<string>("cl_name")
}).ToList();
context.Response.Write("{\"g_name\": " + grid_name + ",\"column\":" + JsonConvert.SerializeObject(column) + "}");
}
catch (Exception e)
{
context.Response.Write("失败:" + e.Message);
}