public CategoryDto selectCategoryById(String CategoryId)
 {
     CategoryManager mgr = new CategoryManager();
     Category obj = new Category();
     obj.CategoryId = CategoryId;
     obj = mgr.selectCategoryById(obj);
     if (obj != null)
     {
         return CategoryDto.createCategoryDTO(obj);
     }
     else
     {
         return null;
     }
 }