How to perform a search with existing SearchIndex in code

Hi, today i have first touch with Kentico Smart Search. I wanted to perform an search request in code and want some results.

I found some Smart Search helper classes. In my approach i use SearchHelper.Search. But an error occured during the search.

Below you can find my simple search test:

public DataSet Search()
    {

        SearchIndexInfo index = SearchIndexInfoProvider.GetSearchIndexInfo("FCBNews");

        var results = SearchHelper.Search(new SearchParameters
        {
            SearchIndexes = index.IndexCodeName,
            CurrentCulture = "de-CH",
            NumberOfResults = 10,
            SearchInAttachments = false,
            SearchSort = "DESC",

        });
        return results;
    }

And the error message:

An exception of type 'System.NotSupportedException' occurred in CMS.Core.dll but was not handled in user code Additional information: [ObjectFactory.CurrentObjectFactory]: Implementation for interface 'ISearchSyntaxHelper' was not found, make sure that assembly with implementation is present in the bin folder of your application, or call ObjectFactory<ISearchSyntaxHelper>.SetDefaultObjectTypeTo<SomeType>() to initialize the default type for this interface.

Any ideas? :-)

Many thanks, Benedikt