Gantt Foreign Key column Validated

I'm trying to find a similar column that is in the grid (foreign key) in the gantt.  I have not been successful.  

1) How would I add a foreign key column (dropdownedit) to the Gantt grid?

2) I tried to setup an edittemplate but it is not binding.    I dropdown list populated but when I select the value, it does not bind.  What am I doing wrong?

<GanttColumn Field=@nameof(CutoverStory.StoryName)>

    <EditTemplate>

        <SfDropDownList TItem="fxDropDown"

                        TValue="int?"

        @bind-Value="@((context as CutoverStory).StoryName)"

                        DataSource="@lstResource">

            <DropDownListFieldSettings Value="SelectValue" Text="DisplayValue"></DropDownListFieldSettings>

        </SfDropDownList>

    </EditTemplate>

</GanttColumn>

    public partial class CutoverStory

    {

        [Key]

        public int Id { get; set; }

        [Required]

        [Display(Name = "Project")]

        public int TaskId { get; set; }

        public int ProjectId { get; set; }

        public int? OriginalId { get; set; }

        public int? ParentId { get; set; }

        public int? Lvl1Id { get; set; }

        [Required]

        [MaxLength(125)]

        [Display(Name = "Story Name")]

        public string StoryName { get; set; } = "";

        [Required]

        [MaxLength(125)]

        [Display(Name = "Task Name")]

        public string TaskName { get; set; } = "";

        [Display(Name = "Start Date")]

        public DateTime? StartDate { get; set; }

        [Display(Name = "End Date")]

        public DateTime? EndDate { get; set; }

        [Display(Name = "Duration")]

        public string? Duration { get; set; } = "";

        [Display(Name = "Progress")]

        public int? Progress { get; set; }

        [Display(Name = "Predecessor")]

        public string? Predecessor { get; set; } = "";

        [Display(Name = "Primary Owner")]

        public int? PrimaryOwner { get; set; }

        [Display(Name = "Day From Zero")]

        public int? DayFromZero { get; set; }

        [Display(Name = "Sort No")]

        public int? SortNo { get; set; }

        [Display(Name = "Chapter")]

        public int? Chapter { get; set; }

        [Display(Name = "Sub Chapter")]

        public int? ChapterSub { get; set; }

        [Display(Name = "Is Build")]

        public bool? IsBuild { get; set; }

        public DateTime ChangeDate { get; set; } = DateTime.Now;

        public int ChangeBy { get; set; } = 1;

        public DateTime AddDate { get; set; } = DateTime.Now;

        public int AddBy { get; set; } = 1;

    }