[Parameter]
public RenderFragment Columns { get; set; }

@inject IDbContextFactory<NorthwindContext> NorthwindContextFactory

<DxGrid Data="Orders"
        EditMode="GridEditMode.EditRow">
    <Columns>
        <DxGridCommandColumn />
        <DxGridDataColumn FieldName="EmployeeId" Caption="Employee" Width="20%">
            <EditSettings>
                <DxComboBoxSettings Data="Employees"
                                    TextFieldName="LastName"
                                    ValueFieldName="EmployeeId"
                                    EditFormat="{1} {2}" >
                    <Columns>
                        <DxListEditorColumn FieldName="EmployeeId" Caption="Id" Width="30px" />
                        <DxListEditorColumn FieldName="FirstName" Caption="Name" />
                        <DxListEditorColumn FieldName="LastName" Caption="Surname" />
                    </Columns>
                </DxComboBoxSettings>
            </EditSettings>
        </DxGridDataColumn>
        <DxGridDataColumn FieldName="ShippedDate" />
        <DxGridDataColumn FieldName="ShipCountry" />
        <DxGridDataColumn FieldName="ShipCity" />
        <DxGridDataColumn FieldName="ShipName" Width="20%" />
    </Columns>
</DxGrid>

@code {
    NorthwindContext Northwind { get; set; }
    List<Order> Orders { get; set; }
    List<Employee> Employees { get; set; }

    protected override async Task OnInitializedAsync() {
        Northwind = NorthwindContextFactory.CreateDbContext();
        Orders = await Northwind.Orders.ToListAsync();
        Employees = await Northwind.Employees.ToListAsync();
    }

    public void Dispose() {
        Northwind?.Dispose();
    }
}

using Microsoft.EntityFrameworkCore;
#nullable disable

namespace Grid.Northwind {
    public partial class NorthwindContext : DbContext {

        public NorthwindContext(DbContextOptions<NorthwindContext> options)
            : base(options) {
        }
        // ...
        public virtual DbSet<Order> Orders { get; set; }
        public virtual DbSet<Employee> Employees { get; set; }
        // ...
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) {
            if(!optionsBuilder.IsConfigured) {
                optionsBuilder.UseSqlServer("Server=.\\sqlexpress;Database=Northwind;Integrated Security=true");
            }
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder) {
            modelBuilder.HasAnnotation("Relational:Collation", "SQL_Latin1_General_CP1_CI_AS");
            // ...
            modelBuilder.Entity<Order>(entity => {
                entity.HasIndex(e => e.CustomerId, "CustomerID");
                entity.HasIndex(e => e.CustomerId, "CustomersOrders");
                entity.HasIndex(e => e.EmployeeId, "EmployeeID");
                entity.HasIndex(e => e.EmployeeId, "EmployeesOrders");
                entity.HasIndex(e => e.OrderDate, "OrderDate");
                entity.HasIndex(e => e.ShipPostalCode, "ShipPostalCode");
                entity.HasIndex(e => e.ShippedDate, "ShippedDate");
                entity.HasIndex(e => e.ShipVia, "ShippersOrders");
                entity.Property(e => e.OrderId).HasColumnName("OrderID");
                entity.Property(e => e.CustomerId)
                    .HasMaxLength(5)
                    .HasColumnName("CustomerID")
                    .IsFixedLength(true);
                entity.Property(e => e.EmployeeId).HasColumnName("EmployeeID");
                entity.Property(e => e.Freight)
                    .HasColumnType("money")
                    .HasDefaultValueSql("((0))");
                entity.Property(e => e.OrderDate).HasColumnType("datetime");
                entity.Property(e => e.RequiredDate).HasColumnType("datetime");
                entity.Property(e => e.ShipAddress).HasMaxLength(60);
                entity.Property(e => e.ShipCity).HasMaxLength(15);
                entity.Property(e => e.ShipCountry).HasMaxLength(15);
                entity.Property(e => e.ShipName).HasMaxLength(40);
                entity.Property(e => e.ShipPostalCode).HasMaxLength(10);
                entity.Property(e => e.ShipRegion).HasMaxLength(15);
                entity.Property(e => e.ShippedDate).HasColumnType("datetime");
            });
            modelBuilder.Entity<Employee>(entity => {
                entity.HasIndex(e => e.EmployeeId, "EmployeeId");
                entity.HasIndex(e => e.LastName, "LastName");
                entity.HasIndex(e => e.FirstName, "FirstName");
                entity.HasIndex(e => e.Title, "Title");
                entity.HasIndex(e => e.BirthDate, "BirthDate");
                entity.HasIndex(e => e.HireDate, "HireDate");
                entity.HasIndex(e => e.Notes, "Notes");
            });
            // ...
            OnModelCreatingPartial(modelBuilder);
        }

        partial void OnModelCreatingPartial(ModelBuilder modelBuilder);
    }
}

public partial class Order {
    public Order() {
        OrderDetails = new HashSet<OrderDetail>();
    }

    public int OrderId { get; set; }
    public string CustomerId { get; set; }
    public int? EmployeeId { get; set; }
    public DateTime? OrderDate { get; set; }
    public DateTime? RequiredDate { get; set; }
    public DateTime? ShippedDate { get; set; }
    public int? ShipVia { get; set; }
    public decimal? Freight { get; set; }
    public string ShipName { get; set; }
    public string ShipAddress { get; set; }
    public string ShipCity { get; set; }
    public string ShipRegion { get; set; }
    public string ShipPostalCode { get; set; }
    public string ShipCountry { get; set; }
}

public partial class Employee {
        public int EmployeeId { get; set; }
        public string LastName { get; set; }
        public string FirstName { get; set; }
        public string Title { get; set; }
        public string TitleOfCourtesy { get; set; }
        public Nullable BirthDate { get; set; }
        public Nullable HireDate { get; set; }
        public string Address { get; set; }
        public string City { get; set; }
        public string Region { get; set; }
        public string PostalCode { get; set; }
        public string Country { get; set; }
        public string HomePhone { get; set; }
        public string Extension { get; set; }
        public byte[] Photo { get; set; }
        public string Notes { get; set; }
        public Nullable<int> ReportsTo { get; set; }
        public string PhotoPath { get; set; }
        public virtual ICollection<Order> Orders { get; set; }
        public string Text => $"{FirstName} {LastName} ({Title})";
        public string ImageFileName => $"Employees/{EmployeeId}.jpg";
    }