How to map IEnumberable<string> convert to string?-CodePudding

Method that accepts two Dal objects =>> Method(DalFirst[] source1, DalSecond[] source2):

source1.Select(
    src => new DataExmaple()
    {
       Id = src.Id,
       ...
       AdditionalField = source2.Select(x => x.Field).ToString()
    }

I get the output name as just type "System.Linq.Enumerable SelectArrayIterator`2[....". With FirstOfDefault => it turns out, but the same values are everywhere.

CodePudding user response：

There is no default string representation of a collection. You'd need to specify how you want the data to render as a string. For example, if you want each value separated by a comma (or any other delimiter) then you can join the collection values with String.Join:

AdditionalField = String.Join(",", source2.Select(x => x.Field))

CodePudding user response：

The problem is this expression:

AdditionalField = source2.Select(x => x.Field).ToString()

At this point, source2 is still the entire DalSecond[] source2 array. You need to do something to map each source1 item to the specific matching source2 value(s). I could give you more, but there's not enough information in the question yet to infer what you really want to do here.