Can't find the way to fill in_raster parameter

Dear All,

I am trying to work with ESRI.ArcGIS.SpatialAnalystTools.CellStatistics, and the input is a set of layers, i couldn't find any way to pass this parameter, I am using c#, I tried Array of objects, List<ILayer>, ILayer<object> and IArray, and all of them failed, can you please help in this issue?

Thank you
Jalal