how to bind grid view in C#

i have gridview and i want bind it from data base but it not bind some Cells. it's class of table:

    [Key]
    [Required]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    [Column("FldKeyId")]
    public int MyKeyId { get; set; }
    [Required]
    public Machine Machine { get; set; }
    [Required]
    public Employee Employee { get; set; }
    [Required]
    public Shift Shift { get; set; }
    [Required]
    [Column ("FldStartTime")]
    public DateTime MyStartTime { get; set; }
    [Required]
    [Column ("FldEndTime")]
    public DateTime MyEndTime { get; set; }
    [Column("FldModificationDate")]
    [Required]
    public DateTime ModificationDate { get; set; }

that's my code for bind

void RefreshBreakGrid()
    {
        dgvcolDate.DataPropertyName = "ModificationDate";
        dgvcolstarttime.DataPropertyName = "MyStartTime";
        dgvcolendtime.DataPropertyName = "MyEndTime";

        dgvcolemployee.DataSource = Employee.GetAllEmployee();
        dgvcolemployee.DisplayMember = "MyName";
        dgvcolemployee.ValueMember = "MyKeyId";
        dgvcolemployee.DataPropertyName = "Employee";


        dgvcolmachine.DataSource = Machine.GetAllMachine();
        dgvcolmachine.DisplayMember = "MyName";
        dgvcolmachine.ValueMember = "MyKeyId";
        dgvcolmachine.DataPropertyName = "MyName";

        dgvcolshift.DataSource = Shift.GetAllShift();
        dgvcolshift.DisplayMember = "MyName";
        dgvcolshift.ValueMember = "MyKeyId";
        dgvcolshift.DataPropertyName = "Shift";

        _Breaks=Break.GetAllBreak();
        dgvBreak.AutoGenerateColumns = false;
        dgvBreak.DataSource = _Breaks;
    }

that's code for getAllBreaks

public static List<Break> GetAllBreak()
    {
        return new ContexManager().Breaks.Where(c => c.MyKeyId != 0).Include(c => c.Machine).Include(c => c.Employee).Include(c => c.Shift).ToList();
    }