@inject IJSRuntime JsInterop

<TelerikGrid Data="@salesTeamMembers" OnRowClick="@OnRowClickHandler" @ref="@GridRef">
    <DetailTemplate>
        @{
            var employee = context as MainModel;
            <TelerikGrid Data="employee.Orders" Pageable="true" PageSize="5">
                <GridColumns>
                    <GridColumn Field="OrderId"></GridColumn>
                    <GridColumn Field="DealSize"></GridColumn>
                </GridColumns>
            </TelerikGrid>
        }
    </DetailTemplate>
    <GridColumns>
        <GridColumn Field="Id"></GridColumn>
        <GridColumn Field="Name"></GridColumn>
    </GridColumns>
</TelerikGrid>

@code {
    List<MainModel> salesTeamMembers { get; set; }
    TelerikGrid<MainModel> GridRef { get; set; }

    async Task OnRowClickHandler(GridRowClickEventArgs args) {
        // After adding this line, it now requires a double click when the InvokeAsync call uses "await"
         var width = JsInterop.InvokeAsync<int>("getWidth");


        var model = args.Item as MainModel;
        int index = salesTeamMembers.IndexOf(model);
        //todo: you may want to take paging into account for example, or use js interop to get the index of the row based on contents from it like id
        if (index > -1) {
            var state = GridRef.GetState();
            state.ExpandedRows = new List<int> { index };

            await GridRef.SetState(state);
        }

    }


    protected override void OnInitialized() {
        salesTeamMembers = GenerateData();
    }

    private List<MainModel> GenerateData() {
        List<MainModel> data = new List<MainModel>();
        for (int i = 0; i < 5; i++) {
            MainModel mdl = new MainModel { Id = i, Name = $"Name {i}" };
            mdl.Orders = Enumerable.Range(1, 15).Select(x => new DetailsModel { OrderId = x, DealSize = x ^ i }).ToList();
            data.Add(mdl);
        }
        return data;
    }

    public class MainModel {
        public int Id { get; set; }
        public string Name { get; set; }
        public List<DetailsModel> Orders { get; set; }
    }

    public class DetailsModel {
        public int OrderId { get; set; }
        public double DealSize { get; set; }
    }
}

Error: System.ObjectDisposedException: Cannot access a disposed object.

Object name: 'DotNetObjectReference`1'.

   at Microsoft.JSInterop.DotNetObjectReference`1.ThrowIfDisposed()

   at Microsoft.JSInterop.JSRuntime.TrackObjectReference[TValue](DotNetObjectReference`1 dotNetObjectReference)

   at Microsoft.JSInterop.Infrastructure.DotNetObjectReferenceJsonConverter`1.Write(Utf8JsonWriter writer, DotNetObjectReference`1 value, JsonSerializerOptions options)

   at System.Text.Json.JsonSerializer.WriteDictionary[TProperty](JsonConverter`1 converter, JsonSerializerOptions options, WriteStackFrame& current, Utf8JsonWriter writer)

   at System.Text.Json.JsonPropertyInfoNotNullable`4.OnWriteDictionary(WriteStackFrame& current, Utf8JsonWriter writer)

   at System.Text.Json.JsonPropertyInfo.WriteDictionary(WriteStack& state, Utf8JsonWriter writer)

   at System.Text.Json.JsonSerializer.HandleDictionary(JsonClassInfo elementClassInfo, JsonSerializerOptions options, Utf8JsonWriter writer, WriteStack& state)

   at System.Text.Json.JsonSerializer.Write(Utf8JsonWriter writer, Int32 originalWriterDepth, Int32 flushThreshold, JsonSerializerOptions options, WriteStack& state)

   at System.Text.Json.JsonSerializer.WriteCore(Utf8JsonWriter writer, Object value, Type type, JsonSerializerOptions options)

   at System.Text.Json.JsonSerializer.WriteCore(PooledByteBufferWriter output, Object value, Type type, JsonSerializerOptions options)

   at System.Text.Json.JsonSerializer.WriteCoreString(Object value, Type type, JsonSerializerOptions options)

   at Microsoft.JSInterop.JSRuntime.InvokeAsync[TValue](String identifier, CancellationToken cancellationToken, Object[] args)

   at Microsoft.JSInterop.JSRuntime.InvokeWithDefaultCancellation[T](String identifier, Object[] args)

   at Telerik.Blazor.Components.Grid.GridHeaderRowBase`1.InitColumnReorderable()

   at Telerik.Blazor.Components.Grid.GridHeaderRowBase`1.OnAfterRenderAsync(Boolean firstRender)

   at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle)

@inject IJSRuntime _js

@* Move JavaScript code to a separate JS file in production *@
<script suppress-error="BL9992">
    function uncheckGrid() {
        var checkboxes = document.querySelectorAll(".no-select .k-grid-checkbox");
        for (var i = 0; i < checkboxes.length; i++) {
            checkboxes[i].checked = false;
        }
    }
</script>

<style>
    .no-select {
        cursor: not-allowed;
    }

    .no-select .k-checkbox {
        pointer-events: none;
    }
</style>

<TelerikGrid Data=@GridData
             SelectionMode="@GridSelectionMode.Multiple"
             SelectedItemsChanged="@((IEnumerable<Employee> employeeList) => OnSelect(employeeList))"
             SelectedItems="@SelectedEmployees"
             Pageable="true"
             Height="400px">
    <GridColumns>
        <GridCheckboxColumn SelectAll="true" OnCellRender="@OnGridCellRender" />
        <GridColumn Field="@nameof(Employee.Name)" />
        <GridColumn Field="@nameof(Employee.Team)" />
        <GridColumn Field="@nameof(Employee.Active)" />
    </GridColumns>
</TelerikGrid>

@if (SelectedEmployees != null)
{
    <ul>
        @foreach (Employee employee in SelectedEmployees)
        {
            <li>
                @employee.Name
            </li>
        }
    </ul>
}

@code {
    private List<Employee> GridData { get; set; } = new List<Employee>();

    private IEnumerable<Employee> SelectedEmployees { get; set; } = new List<Employee>();

    private void OnGridCellRender(GridCellRenderEventArgs args)
    {
        var product = (Employee)args.Item;
        if (!product.Active)
        {
            args.Class = "no-select";
        }
    }

    protected void OnSelect(IEnumerable<Employee> newSelected)
    {
        var validItemsToSelect = newSelected.Where(x => x.Active);
        SelectedEmployees = validItemsToSelect;
        if (validItemsToSelect.Count() < newSelected.Count())
        {
            _js.InvokeVoidAsync("uncheckGrid");
        }
    }

    protected override void OnInitialized()
    {
        for (int i = 1; i <= 7; i++)
        {
            GridData.Add(new Employee()
            {
                EmployeeId = i,
                Name = $"Employee {i}",
                Team = $"Team {i % 3 + 1}",
                Active = i % 2 == 0
            });
        }
    }

    public class Employee
    {
        public int EmployeeId { get; set; }
        public string Name { get; set; } = string.Empty;
        public string Team { get; set; } = string.Empty;
        public bool Active { get; set; }
    }
}

Error: System.ArgumentNullException: Value cannot be null. (Parameter 'nullableType')