public IGridColumn Column { get; }

@inject WeatherForecastService ForecastService

<DxGrid Data="@Data"
        RowClick="OnRowClick"
        AllowGroup="true"
        ShowGroupPanel="true">
    <Columns>
        <DxGridDataColumn FieldName="Date" Caption="Date" />
        <DxGridDataColumn FieldName="TemperatureC" Caption="@("Temp. (\x2103)")" Width="120px" GroupIndex="0"/>
        <DxGridDataColumn FieldName="TemperatureF" Caption="@("Temp. (\x2109)")" Width="120px" />
        <DxGridDataColumn FieldName="Forecast" Caption="Forecast" />
        <DxGridDataColumn FieldName="CloudCover" Caption="CloudCover" GroupIndex="1"/>
    </Columns>
</DxGrid>

@Alert

@code {
    public string Alert { get; set; } = "";
    object Data { get; set; }

    protected override void OnInitialized() {
        Data = ForecastService.GetForecast();
    }

    void OnRowClick(GridRowClickEventArgs e) {
        Alert = $"Data rows are grouped by the {e.Column.Caption} column. ";
    }
}

using System;

public class WeatherForecast {
    public DateTime Date { get; set; }
    public int TemperatureC { get; set; }
    public double TemperatureF => Math.Round((TemperatureC * 1.8 + 32), 2);
    public string Forecast { get; set; }
    public string CloudCover { get; set; }
    public bool Precipitation { get; set; }
}

using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Threading;
    using System.Threading.Tasks;

    public class WeatherForecastService {
        private List<WeatherForecast> Forecast { get; set; }

        private static string[] CloudCover = new[] {
            "Sunny", "Partly cloudy", "Cloudy", "Storm"
        };

        Tuple<int, string>[] ConditionsForForecast = new Tuple<int, string>[] {
            Tuple.Create( 22 , "Hot"),
            Tuple.Create( 13 , "Warm"),
            Tuple.Create( 0 , "Cold"),
            Tuple.Create( -10 , "Freezing")
        };

        public WeatherForecastService() {
            Forecast = CreateForecast();
        }

        private List<WeatherForecast> CreateForecast() {
            var rng = new Random();
            DateTime startDate = DateTime.Now;
            return Enumerable.Range(1, 15).Select(index => {
                var temperatureC = rng.Next(-10, 30);
                return new WeatherForecast {
                    Date = startDate.AddDays(index),               
                    TemperatureC = temperatureC,
                    CloudCover = CloudCover[rng.Next(0, 4)],
                    Precipitation = Convert.ToBoolean(rng.Next(0, 2)),
                    Forecast = ConditionsForForecast.First(c => c.Item1 <= temperatureC).Item2
                };
            }).ToList();
        }

        public IEnumerable<WeatherForecast> GetForecast() {
            return Forecast.ToArray();
        }
        // ...
}

// ...
builder.Services.AddSingleton<WeatherForecastService>();