c# - タイプ 'System.Collections.Generic.List を暗黙的に変換できません' から 'System.Collections.Generic.List'

Question

しばらくの間、このエラーで立ち往生しています。基本的に私は 2 つの C# クラス ライブラリ HeldDeskBusinessData と HelpDeskBusinessUser (タイトルの短縮形) を持っています。

HelpDeskBusinessData から

     public List<Employee> GetAll()
    {
        HelpDeskDBEntities dbContext = new HelpDeskDBEntities();
        List<Employee> employees = dbContext.Employees.ToList();
        List<Employee> busEmployees = new List<Employee>();

        try
        {
            foreach (Employee emp in employees)
            {
                Employee empBus = new Employee();
                empBus.Title = emp.Title;
                empBus.FirstName = emp.FirstName;
                empBus.LastName = emp.LastName;
                empBus.PhoneNo = emp.PhoneNo;
                empBus.Email = emp.Email;
                empBus.DepartmentID = emp.DepartmentID;
                empBus.EmployeeID = emp.EmployeeID;
                busEmployees.Add(empBus);
            }//end foreach
        }//end try
        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }//end catch
        return busEmployees;
    }//end getallemployees

From HelpdeskBusinessuser にエラーが含まれています (ラベル)

    public List<EmployeeBusinessUser> GetAll()
    {

            EmployeeBusinessData empBD = new EmployeeBusinessData();
            List<Employee> empL = new List<Employee>();
            List<EmployeeBusinessUser> empBU = new List<EmployeeBusinessUser>();
            empL = empBD.GetAll(); /*error cant explicitly convert.  */
            try
            {
                foreach (Employee emps in empL)
                {
                    EmployeeBusinessUser empBus = new EmployeeBusinessUser();
                    empBus.Title = emps.Title;
                    empBus.FirstName = emps.FirstName;
                    empBus.LastName = emps.LastName;
                    empBus.PhoneNo = emps.PhoneNo;
                    empBus.Email = emps.Email;
                    empBus.DepartmentID = emps.DepartmentID;
                    empBU.Add(empBus);
                }//end foreach
            }//end try
            catch (Exception ex)
            {
                ErrorRoutine(ex, "EmployeeBusinessUser", "GetAll");
            }
            return empBU;
        }//end getallemployees

誰でも解決方法を知っていますか？