sorting issue

In my app I have a list of one class,, want to sort the alphanumeric value and I want my result as, N1-1,N1-20,N1-100,N1-10000,N1-8100.How can I get this?                 

List employeeList = new List()
  {         new Employee { Name = "N1", Salary = "N1-1" } ,                    
                  ...

        SortSalary sortSal = new SortSalary();
        employeeList.Sort(sortSal);

  }

class SortSalary: IComparer
{
    #region IComparer Members

    public int Compare(Employee x, Employee y)
    {
      
        return string.Compare(x.Salary, y.Salary);
    }

    #endregion
}