public class ActivityResource
    {
        public int ActivityId { get; set; }

        public int ResourceId { get; set; }

        public double Sequence { get; set; }

        public DateTime ScheduledStart { get; set; }

        public DateTime ScheduledEnd { get; set; }

        public double ScheduledDuration { get; set; }



        public Activity Activity { get; set; }

        public Resource Resource { get; set; }
    }

 public class Activity
    {
        public int Id { get; set; }
        public int Number { get; set; }
        public string Name { get; set; } = "New Activity";
        public string Description { get; set; }

        public ICollection<Resource> Resources { get; set; }

        public List<ActivityResource> ActivityResources { get; set; }

    }

public class Resource
    {
        public int Id { get; set; }
        public string Name { get; set; } = "New Resource";
        public string Description { get; set; }

        public int ResourceTypeId { get; set; }
        public virtual ResourceType ResourceType { get; set; }



        public ICollection<Activity> Activities { get; set; }

        public List<ActivityResource> ActivityResources { get; set; }
    }

Controller:
 public async Task UpdateActivityResourceScheduleAsync(ActivityResource schedule)
        {
            // Getting the Schedule that is in the database.
            var targetedSchedule = _ctx.ActivityResources.FirstOrDefault(r => r.ActivityId == schedule.ActivityId && r.ResourceId == schedule.ResourceId);
            bool resquence = false;

            if (targetedSchedule != null)
            {

                if (targetedSchedule.Sequence != schedule.Sequence)
                {
                    resquence = true;
                }
                // Assigning the properties.
                targetedSchedule.Sequence = schedule.Sequence;
                targetedSchedule.ScheduledStart = schedule.ScheduledStart;
                targetedSchedule.ScheduledEnd = schedule.ScheduledEnd;
                targetedSchedule.ScheduledDuration = schedule.ScheduledDuration;
                targetedSchedule.Activity = schedule.Activity;
                targetedSchedule.Resource = schedule.Resource;
                targetedSchedule.ActivityId = schedule.ActivityId;
                targetedSchedule.ResourceId = schedule.ResourceId;
                targetedSchedule.Activity = _ctx.Activities.FirstOrDefault(aId => aId.Id == schedule.ActivityId);
                targetedSchedule.Resource = _ctx.Resources.FirstOrDefault(rId => rId.Id == schedule.ResourceId);

               

            }

                // Updating the properties.
                _ctx.ActivityResources.Update(targetedSchedule);
                await _ctx.SaveChangesAsync();
}

Razor Page:
<TelerikGrid Data="@SchedulesList" Height="550px" FilterMode="@GridFilterMode.FilterMenu"
                 Sortable="true"
                 Pageable="true"
                 PageSize="20"
                 Resizable="true"
                 Reorderable="true"
                 RowDraggable="true"
                 OnStateInit="@((GridStateEventArgs<VentureBlazor.Models.ActivityResource> args) => OnStateInit(args))"
                 OnRowDrop="@((GridRowDropEventArgs<VentureBlazor.Models.ActivityResource> args) => OnRowDropHandler(args))"
                 EditMode="@GridEditMode.Incell"
                 OnUpdate="@UpdateHandler"
                 OnDelete="@DeleteHandler">
                  <DetailTemplate>
                    @{
                        var schedule = context as VentureBlazor.Models.ActivityResource;
                        <TelerikGrid Data="@schedule.Activity.Resources" Pageable="true" PageSize="5">
                            <GridColumns>
                                <GridColumn Field="Name"></GridColumn> 
                                <GridColumn Field="Description"></GridColumn>
                            </GridColumns>
                        </TelerikGrid>
                       
                    }
                </DetailTemplate> 
                 <GridToolBar>
@*            <GridCommandButton Command="Add" Icon="plus" Primary="true">Add Schedule</GridCommandButton>
*@        </GridToolBar>
        <GridColumns>
@*            <GridColumn Field="@(nameof(VentureBlazor.Models.ActivityResourceSchedule.Id))" Editable="false" />
*@            <GridColumn Title="Activity Id" Field="Activity.Id" Editable="false"/>
            <GridColumn Title="Resource Id" Field="Resource.Id" Editable="false"/>
            <GridColumn Field="@(nameof(VentureBlazor.Models.ActivityResource.Sequence))" />           
            <GridColumn Field="@(nameof(VentureBlazor.Models.ActivityResource.ScheduledStart))" />
            <GridColumn Field="@(nameof(VentureBlazor.Models.ActivityResource.ScheduledEnd))" />
            <GridColumn Field="@(nameof(VentureBlazor.Models.ActivityResource.ScheduledDuration))" />           
            <GridColumn Title="Activity Name" Field="@(nameof(VentureBlazor.Models.ActivityResource.ActivityId))">
                <EditorTemplate>
                    @{
                        CurrentlyEditedSchedule = context as VentureBlazor.Models.ActivityResource;
                        <TelerikDropDownList Data="@ActivitiesList"
                        @bind-Value="@CurrentlyEditedSchedule.ActivityId" 
                        TextField="@nameof(Activity.Name)"
                        ValueField="@nameof(Activity.Id)"
                        >
                        
                        </TelerikDropDownList>
                    }
                </EditorTemplate>
                <Template>
                    @{
                    int aId = (context as VentureBlazor.Models.ActivityResource).ActivityId;
                    Activity matchingPos = ActivitiesList.FirstOrDefault(a => a.Id == aId);
                    string textToRender = matchingPos != null ? matchingPos.Name : "Unknown";
                    <text>@textToRender</text>
                }
                </Template>
            </GridColumn>
            <GridColumn Title="Resource Name" Field="@(nameof(VentureBlazor.Models.ActivityResource.ResourceId))">
                <EditorTemplate>
                    @{
                        CurrentlyEditedSchedule = context as VentureBlazor.Models.ActivityResource;
                        <TelerikDropDownList Data="@ResourcesList"
                        @bind-Value="@CurrentlyEditedSchedule.ResourceId" 
                        TextField="@nameof(VentureBlazor.Models.Resource.Name)"
                        ValueField="@nameof(VentureBlazor.Models.Resource.Id)"
                        >
                        
                        </TelerikDropDownList>
                    }
                </EditorTemplate>
                <Template>
                    @{
                    int rId = (context as VentureBlazor.Models.ActivityResource).ResourceId;
                    VentureBlazor.Models.Resource matchingPos = ResourcesList.FirstOrDefault(r => r.Id == rId);
                    string textToRender = matchingPos != null ? matchingPos.Name : "Unknown";
                    <text>@textToRender</text>
                }
                </Template>
            </GridColumn>
            <GridCommandColumn Width="200px" Resizable="false">
                <GridCommandButton Command="Save" Icon="save" ShowInEdit="true">Update</GridCommandButton>
                <GridCommandButton Command="Edit" Icon="edit" Primary="true">Edit</GridCommandButton>
                <GridCommandButton Command="Delete" Icon="delete">Delete</GridCommandButton>
                <GridCommandButton Command="Cancel" Icon="cancel" ShowInEdit="true">Cancel</GridCommandButton>
            </GridCommandColumn>
        </GridColumns>   
    </TelerikGrid>

@code {

    private List<VentureBlazor.Models.ActivityResource> SchedulesList { get; set; }
    private List<VentureBlazor.Models.Activity> ActivitiesList  { get; set; }
    private List<VentureBlazor.Models.Resource> ResourcesList { get; set; }
    private VentureBlazor.Models.ActivityResource CurrentlyEditedSchedule { get; set; }
    private VentureBlazor.Models.Activity NewActivity = new VentureBlazor.Models.Activity();
    private VentureBlazor.Models.Resource NewResource = new VentureBlazor.Models.Resource();
    private ActivityScheduleRepository repo;
    int selectedValue { get; set; }


    protected override async Task OnInitializedAsync()
    {        
        repo = new ActivityScheduleRepository(ContextFactory.CreateDbContext());
        await LoadSchedules();
    }

    public async Task LoadSchedules()
    {
        SchedulesList = await repo.GetAllActivityResourceSchedulesAsync();
        ActivitiesList = await repo.GetAllActivitiesAsync();
        ResourcesList = await repo.GetAllResourcesAsync();
    }

 public async Task UpdateHandler(GridCommandEventArgs args)
    {        
        await repo.UpdateActivityResourceScheduleAsync((VentureBlazor.Models.ActivityResource)args.Item);
        await LoadSchedules();
    }

}

    public class IPAddressComparer : IComparer<IpAddress>
    {
        public int Compare(IpAddress a, IpAddress b)
        {
            return Enumerable.Zip(
                a.Address.Split('.'),
                b.Address.Split('.'),
                (x, y) => int.Parse(x).CompareTo(int.Parse(y)))
                             .FirstOrDefault(i => i != 0);
        }
    }