I need some help on a little problem: I have a List a and a List b. List b contains a MigrationID which is the ID of the objects in List a. Now I want to match the objects with the same MigrationID and ID and create out of that a new SyncObject which contains obj a, obj b and a SyncID. But i dont want to use loops because i think it´s underperforming.

For example:

if b.MigrationID =  a.ID => create new SyncObejct(SyncID, obj a, obj b)

My Code now looks a bit like this:

private class SyncObject
    {
        private Guid syncID { get; set; }
        private ItemA aItem { get; set; }
        private ItemB bItem { get; set; }
    }

public void SynchObjAToObjB<T, A>() where T : ItemA, new() where A : ItemB, new()
    {
        List<T> listA aItems;
        List<A> listB bItems;

        //here mapping

    }

The list´s both are filled with data.

Thank you!

CodePudding user response：

Perhaps something like this:

class ItemA
{
    public Guid Id { get; set; }
    public string MetaData { get; set; }
}
class ItemB
{
    public Guid MigrationID { get; set; }
    public string MetaData { get; set; }
}
class SyncObject
{
    public Guid syncID { get; set; }
    public ItemA aItem { get; set; }
    public ItemB bItem { get; set; }
}

void Main()
{
    // setup example data
    var listA  = new[] 
    { 
        new ItemA { Id = Guid.NewGuid() }, // no match in listB
        new ItemA { Id = Guid.NewGuid() }, // match in listB and will be in the result
        new ItemA { Id = Guid.NewGuid() }  // match in listB and will be in the result
    };
    var listB  = new[] { 
        new ItemB { MigrationID = listA[1].Id },
        new ItemB { MigrationID = listA[2].Id} 
    };

    // the "mapping"
    var result = listA.Join(listB, a => a.Id, b => b.MigrationID, (a, b) => 
        new SyncObject
        { 
            aItem = a, 
            bItem = b, 
            syncID = a.Id
        });
}

And the result will be a list with matching elements