private void RemoveSkill()
 {
     if (SelectedSkill != null)
     {
         UnselectedSkillList.Add(SelectedSkill);
         SelectedSkillList.Remove(SelectedSkill);
     }
 }
 private void AddSkill()
 {
     if (UnselectedSkill != null)
     {
         SelectedSkillList.Add(UnselectedSkill);
         UnselectedSkillList.Remove(UnselectedSkill);
     }
 }