I have to convert System.Collections.Generic.IDictionary<string, decimal> to System.Collections.Generic.Dictionary<string, decimal>, and i can't. I tried the ToDictionary method and can't specify right arguments. I've tried the following: // my dictionary is PlannedSurfaces (of type IDictionary<string, decimal>) blabla.ToDictionary<string, decimal>(localConstruction.PlannedSurfaces)