<TelerikGrid Data="@gridDataExpando" Width="100%" Sortable="false" Pageable="false" Resizable="true" ShowColumnMenu="false"
             ScrollMode="@GridScrollMode.Scrollable"
             Height="100%"
             EditMode="@GridEditMode.Incell"
             OnUpdate="@UpdateHandlerExpando"
             OnEdit="@EditHandler">
   <GridColumns>
      @{
         var firstItem = gridDataExpando.FirstOrDefault();
         if (firstItem != null)
         {
            var dictionaryItem = firstItem as IDictionary<string, object>;
            foreach (var item in dictionaryItem)
            {
               if (!item.Key.Contains("Id"))
               {
                  <GridColumn Field="@(item.Key)" FieldType="@(this.GetDataType(item.Key))" Width="140px" DisplayFormat="{0:hh:mm:ss tt}">
                     <HeaderTemplate>
                        <span>@item.Key</span>
                    </HeaderTemplate>
                   </GridColumn>
               }
            }
         }
      }
   </GridColumns>
</TelerikGrid>

@* Use the Template to render the list of columns and add some custom styles *@ 

<TelerikGrid Data="@MyData"
             Pageable="true"
             PageSize="5"
             Width="700px"
             FilterMode="@GridFilterMode.FilterMenu"
             Sortable="true"
             ShowColumnMenu="true">
     <GridSettings>
     
     <GridColumnMenuSettings Sortable="true"
                             Lockable="false"
                             FilterMode="@ColumnMenuFilterMode.None" />
 </GridSettings>
    <GridColumns> 

 <GridCheckboxColumn Width="80px" HeaderClass="header-select-all" />   
        <GridColumn Field="@(nameof(SampleData.Id))" Width="80px" Title="Id" Id="id-column-id" />
        <GridColumn Field="@(nameof(SampleData.FirstName))" Title="First Name" Id="firstname-column-id" />
        <GridColumn Field="@(nameof(SampleData.LastName))" Title="Last Name" Id="lastname-column-id" />
        <GridColumn Field="@(nameof(SampleData.CompanyName))" Title="Company" Id="companyname-column-id" />
        <GridColumn Field="@(nameof(SampleData.Team))" Title="Team" Id="team-column-id" />
        <GridColumn Field="@(nameof(SampleData.HireDate))" Title="Hire Date" Id="hiredate-column-id" />
    </GridColumns>
</TelerikGrid>

@code {
    public string TextboxValue { get; set; } = string.Empty;

    public IEnumerable<SampleData> MyData = Enumerable.Range(1, 30).Select(x => new SampleData
    {
        Id = x,
        FirstName = $"FirstName {x}",
        LastName = $"LastName {x}",
        CompanyName = $"Company {x}",
        Team = "team " + x % 5,
        HireDate = DateTime.Now.AddDays(-x).Date
    });

    public class SampleData
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string CompanyName { get; set; }
        public string Team { get; set; }
        public DateTime HireDate { get; set; }
    }
}

@using System.ComponentModel.DataAnnotations

<TelerikGrid Data="@GridData"
             EditMode="@GridEditMode.Incell"
             OnEdit="@OnGridEdit"
             OnUpdate="@OnGridUpdate">
    <GridColumns>
        <GridColumn Field="@nameof(SampleModel.Name)" />
        <GridColumn Field="@nameof(SampleModel.Min)" />
        <GridColumn Field="@nameof(SampleModel.Max)" />
    </GridColumns>
</TelerikGrid>

<TelerikNotification @ref="@NotificationRef"
                     HorizontalPosition="@NotificationHorizontalPosition.Center"
                     VerticalPosition="@NotificationVerticalPosition.Top" />

@code {
    private TelerikNotification? NotificationRef { get; set; }

    private List<SampleModel> GridData { get; set; } = new();

    private bool ShouldCancelOnEdit { get; set; }

    private int LastId { get; set; }

    private void OnGridEdit(GridCommandEventArgs args)
    {
        if (ShouldCancelOnEdit)
        {
            ShouldCancelOnEdit = false;
            args.IsCancelled = true;
        }
    }

    private void OnGridUpdate(GridCommandEventArgs args)
    {
        var updatedItem = (SampleModel)args.Item;

        if (updatedItem.Min > updatedItem.Max)
        {
            NotificationRef?.Show(new NotificationModel()
            {
                ThemeColor = ThemeConstants.Notification.ThemeColor.Error,
                Text = "Min must be smaller than Max"
            });

            args.IsCancelled = true;
            ShouldCancelOnEdit = true;
        }
        else
        {
            var originalItemIndex = GridData.FindIndex(i => i.Id == updatedItem.Id);

            if (originalItemIndex != -1)
            {
                GridData[originalItemIndex] = updatedItem;
            }

            ShouldCancelOnEdit = false;
        }
    }

    protected override void OnInitialized()
    {
        for (int i = 1; i <= 5; i++)
        {
            GridData.Add(new SampleModel()
            {
                Id = ++LastId,
                Name = $"SampleModel {LastId}",
                Min = Random.Shared.Next(1, 10),
                Max = Random.Shared.Next(11, 20)
            });
        }
    }

    public class SampleModel
    {
        public int Id { get; set; }
        [Required]
        public string Name { get; set; } = string.Empty;
        public int Min { get; set; }
        public int Max { get; set; }
    }
}

@using Telerik.DataSource

<h2>No Aggregates</h2>

<p><code>OnStateInitCounter1:</code> @OnStateInitCounter1</p>
<TelerikGrid Data="@GridData"
             TItem="@SampleModel"
             Groupable="true"
             OnStateInit="@OnGridStateInit1">
    <GridAggregates>

    </GridAggregates>
    <GridColumns>
        <GridColumn Field="@nameof(SampleModel.Name)" />
        <GridColumn Field="@nameof(SampleModel.GroupName)" />
    </GridColumns>
</TelerikGrid>

<h2>With Aggregates</h2>

<p><code>OnStateInitCounter2:</code> @OnStateInitCounter2</p>
<TelerikGrid Data="@GridData"
             TItem="@SampleModel"
             Groupable="true"
             OnStateInit="@OnGridStateInit2">
    <GridAggregates>
        <GridAggregate Field="@nameof(SampleModel.Name)" Aggregate="@GridAggregateType.Count" />
    </GridAggregates>
    <GridColumns>
        <GridColumn Field="@nameof(SampleModel.Name)" />
        <GridColumn Field="@nameof(SampleModel.GroupName)" />
    </GridColumns>
</TelerikGrid>

<h2>With Aggregates and Workaround</h2>

<p><code>OnStateInitCounter3:</code> @OnStateInitCounter3</p>
<TelerikGrid Data="@GridData"
             TItem="@SampleModel"
             Groupable="true"
             OnStateInit="@OnGridStateInit3">
    <GridAggregates>
        <GridAggregate Field="@nameof(SampleModel.Name)" Aggregate="@GridAggregateType.Count" />
    </GridAggregates>
    <GridColumns>
        <GridColumn Field="@nameof(SampleModel.Name)" />
        <GridColumn Field="@nameof(SampleModel.GroupName)" />
    </GridColumns>
</TelerikGrid>

@code {
    private int OnStateInitCounter1 { get; set; }
    private int OnStateInitCounter2 { get; set; }
    private int OnStateInitCounter3 { get; set; }

    private void OnGridStateInit1(GridStateEventArgs<SampleModel> args)
    {
        ++OnStateInitCounter1;

        args.GridState.GroupDescriptors.Add(new GroupDescriptor
        {
            Member = nameof(SampleModel.GroupName)
        });
    }

    private void OnGridStateInit2(GridStateEventArgs<SampleModel> args)
    {
        ++OnStateInitCounter2;

        args.GridState.GroupDescriptors.Add(new GroupDescriptor
        {
            Member = nameof(SampleModel.GroupName)
        });
    }

    private void OnGridStateInit3(GridStateEventArgs<SampleModel> args)
    {
        ++OnStateInitCounter3;

        args.GridState.GroupDescriptors = new List<GroupDescriptor>();
        // OR
        args.GridState.GroupDescriptors.Clear();

        args.GridState.GroupDescriptors.Add(new GroupDescriptor
        {
            Member = nameof(SampleModel.GroupName)
        });
    }

    private List<SampleModel> GridData { get; set; } = new();

    protected override void OnInitialized()
    {
        for (int i = 1; i <= 4; i++)
        {
            GridData.Add(new SampleModel()
            {
                Id = i,
                Name = $"Name {i}",
                GroupName = $"Group {i % 2 + 1}"
            });
        }
    }

    public class SampleModel
    {
        public int Id { get; set; }
        public string Name { get; set; } = string.Empty;
        public string GroupName { get; set; } = string.Empty;
    }
}