ant-design-blazor/site/AntDesign.Docs/Demos/Components/Table/demo/TreeData.razor

@using System.ComponentModel

<Table DataSource="_data" TreeChildren="item=>item.Children">
    <Selection CheckStrictly />
    <Column @bind-Field="@context.Name" />
    <Column @bind-Field="@context.Age" Width="12%" />
    <Column @bind-Field="@context.Address" Width="30%" />
</Table>

@code {
    Data[] _data;

    protected override async Task OnInitializedAsync()
    {
        await base.OnInitializedAsync();

        await Task.Delay(500);

        _data = data;
        await InvokeAsync(StateHasChanged);

        await Task.Delay(500);

        _data[1].Children = new Data[]
        {
            new() {
                Key = "21",
                Name = "Jim Green",
                Age = 42,
                Address = "London No. 1 Lake Park",
            },
        };
    }

    Data[] data =
{
        new() {
            Key = "1",
            Name = "John Brown sr.",
            Age = 60,
            Address = "New York No. 1 Lake Park",
            Children = new Data[] {
                new() {
                    Key = "11",
                    Name = "Jim Green",
                    Age = 42,
                    Address = "London No. 1 Lake Park",
                },
                new() {
                    Key= "12",
                    Name= "John Brown jr.",
                    Age=30,
                    Address= "New York No. 3 Lake Park",
                    Children=new Data[] {
                          new() {
                              Key= "121",
                              Name= "Jimmy Brown",
                              Age= 16,
                              Address= "New York No. 3 Lake Park",
                        },
                    }
                },
                new() {
                    Key= "13",
                    Name= "Jim Green sr.",
                    Age= 72,
                    Address= "London No. 1 Lake Park",
                    Children= new Data[]{
                        new() {
                            Key= "131",
                            Name= "Jim Green",
                            Age= 42,
                            Address= "London No. 2 Lake Park",
                            Children= new Data[] {
                                new() {
                                    Key= "1311",
                                    Name= "Jim Green jr.",
                                    Age= 25,
                                    Address= "London No. 3 Lake Park",
                                },
                                new() {
                                   Key= "1312",
                                   Name= "Jimmy Green sr.",
                                   Age= 18,
                                   Address= "London No. 4 Lake Park",
                                },
                            },
                        },
                    },
                },
            },
        },
        new() {
            Key = "2",
            Name = "Joe Black",
            Age = 32,
            Address = "Sidney No. 1 Lake Park",
        },
    };

    public class Data
    {
        [DisplayName("Key")]
        public string Key { get; set; }

        [DisplayName("Name")]
        public string Name { get; set; }

        [DisplayName("Age")]
        public int Age { get; set; }

        [DisplayName("Address")]
        public string Address { get; set; }

        public Data[] Children { get; set; }
    }
}