/// <summary>
		/// Initializes the tree
		/// </summary>
		public void SetStructure()
		{
			departments = model.GetDepartments();
			employees = model.GetEmployees();
			Department rootDepartment = departments.First(d => d.ParentDepartmentID == null);
			if(rootDepartment.ParentDepartmentID != null)
			{
				throw new ArgumentException("Company department not found");
			}
			company = new TreeNode(rootDepartment.Name) { Tag = rootDepartment.ID};
			Guid id = rootDepartment.ID;
			GetDepartmentStructure(company, id);
			view.ShowTreeStructure(company);
		}