Custom select items in Query<object> using Dapper - dapper

Question

I am new in Dapper.
I want to select dynamic items from conn.Query<>() that it execute a stored procedure in SQL.
My code is similar to :
connection.Open();
var parameters = new DynamicParameters();
parameters.Add("#name", x.GetValue<string>("Name"));
parameters.Add("#lastname", x.GetValue<string>("LastName"));
var query = connection.Query<Costumer>(sql: "GetCostumer", param: parameters, commandType: CommandType.StoredProcedure);
and my stored procedure is similar to:
select * from Costumer where name = #Name and lastname = #lastname
In entity framework i can resolve my problem by this code:
IQueryable<User> query = container.GetQuery<Users>();
var finalResult = (from item in query
select new {
item.name,
item.lastname
}).ToList();

Answer 1

If the question is about selecting just the two columns, then at the simplest level, you can just do exactly what you are already doing, i.e.
var finalResult = (from item in query
select new {
item.Name,
item.LastName
}).ToList();
Note that this does fetch all the columns back to the client, and then re-maps there. If you want to do the column filtering at the server, then you'll need to use something like INSERT EXEC with a subsequent SELECT, i.e.
DECLARE #table_var TABLE (cols)
INSERT INTO #table_var (cols) EXEC proc {args}
SELECT foo, bar FROM #table_var
Although a cleaner implementation might be to expose a UDF - then you can just use:
SELECT foo, bar FROM dbo.SomeFunction(args);
As an aside, if the <Costumer> type doesn't already exist, there is a way to avoid the intermediate type via dynamic and the non-generic Query method, but it is actually slightly less efficient than the above, so should be used sparingly.
Note also that you don't need DynamicParameters in this case; you could just use:
var parameters = new {
name = x.GetValue<string>("Name"),
lastname = x.GetValue<string>("LastName")
};
var query = connection.Query<Costumer>("GetCostumer", parameters,
commandType: CommandType.StoredProcedure);