cast IGH_Goo to Integer?

Good evening,

Can somebody help me, cast IGH_Goo to Integer?

my code(C#) is below,

GH_Structure<IGH_Goo> Tree = new GH_Structure<IGH_Goo>();
DA.GetDataTree<IGH_Goo>(0, out Tree);

GH_Structure<IGH_Goo> TreeOut = new GH_Structure<IGH_Goo>();

       switch (S) {
           case 0:
               for (int i = 0; i < (int) Tree.get_DataItem(0); i++)
               {
                   TreeOut.Append(null, new GH_Path(0));
               }
               break;

          case 1:
               for (int i = 0; i < Tree.Branches.Count; i++) {
                   TreeOut.Append(null, Tree.get_Path(i));
               }

               break;

          and so on.....

          }

I tried to convert IGH_Goo to Integer, but It will not work.

not only

(int) Tree.get_DataItem(0)

but also

Convert.ToInt32(Tree.get_DataItem(0))

won't work.

How can I make it??