C# concat/merge of dynamic type variables

Question

in a for loop I receive results from a db as dynamic type

dynamic {system.collections.generic.List<object>}

I need to collect these results into one single variable.

I tried defining a variable

 dynamic results = new List<object>();

and then

 var queryResults = _dbManager.Query(query);
 results = results.Concat(queryResults);

but I have this exception:

 System.Collections.Generic.List<object> does non contain a definition for 'Concat'

I can't find a solution. Do you how can I do this? Thanks!

Answer 1

The problem is that dynamic types and extension methods don't work well together (read the explanation of Eric Lippert on the why). You have to call the extension method yourself as a static method (which it actually is):

var l = Enumerable.Concat(results, queryResults);