如何获取列表<anonymous type>由 Linq 在 using 语句之外生成？</anonymous>

Question

Got a query using the using statement, which means once it ends the object created gets disposed.

using (Context context = new())
{
    var records = context.PoRecords
        .Join(
            context.PoStatuses,
            record => record.PoStatus,
            status => status.Id,
            (record, status) => new
            {
                record.PoNumber,
                record.PrNumber,
                Status = status.Name,
            }
        ).ToList();
}

How can I get that list outside of that using? What I think I have to do is create a custom class for that query, declare a list of that type outside the using and fill it with the contents of the query, I've done that when I query the whole table, but, since this is joining tables I can't just declare List<CustomType> records =...querywithjoins... because the list Linq is returning is of an anonymous type. I'd have to do that outside the using, kind of like this:

List<CustomType> records;

using (Context context = new()){
    records = TheWholeQuery.ToList();
}

Another way I thought of doing it was, since I am listing the results of the query in a list view with a foreach, creating new objects of the custom type and add them into the new list, but, that means I'd have to iterate through each and every query I do, and I don't intend to do that everytime.

Is there a way to do this? Or a workaround??

Answer 1

You could use a tuple if you don't want to define a class although I have found in these circumstances it's usually ends up being easier to just define the class.

List<Tuple<int, int, string>> records = null; 

using (Context context = new())
{
    records = context.PoRecords
        .Join(
            context.PoStatuses,
            record => record.PoStatus,
            status => status.Id,
                    (record, status) => new Tuple<int, int, string>(
                        record.PoNumber,
                        record.PrNumber,
                        status.Name
                    )
        ).ToList();
}

Answer 2

If u don't want to remove using statement u can just convert your list with anonymous type to list of 'CustomType'

so..

List<CustomType> records;
using (Context context = new())
{
    records = context.PoRecords
    .Join(
        context.PoStatuses,
        record => record.PoStatus,
        status => status.Id,
        (record, status) => new CustomType()
        {
            PoNumber = record.PoNumber,
            PrNumber = record.PrNumber,
            Status = status.Name,
        }
    ).ToList();

}