DxGrid.CustomGroup Event
Enables you to implement custom logic used to group data in the grid.
Namespace: DevExpress.Blazor
Assembly:
DevExpress.Blazor.v24.1.dll
NuGet Package:
DevExpress.Blazor
Declaration
[Parameter]
public Action<GridCustomGroupEventArgs> CustomGroup { get; set; }
Parameters
Follow the steps below to implement custom logic used to group grid data.
- Set the DxGridDataColumn.GroupInterval property to
GridColumnGroupInterval.Custom.
- Handle the
DxGrid.CustomGroup event and compare column values based on your custom logic. Use the event argument’s Value1 and Value2 properties to access the current column’s values. Call the GetRow1Value and GetRow2Value methods to obtain values of other columns. If the compared values belong to the same group, set the SameGroup property to true.
- In the event handler, set the Handled property to
true to prevent the default comparison mechanism from being invoked.
You can also handle the CustomizeGroupValueDisplayText event to customize text for group rows.
The following code snippet implements custom group logic for the Unit Price column. Data are grouped for the following intervals: $0.00 - $10.00, $10.00 - $20.00, and so on.
@using Microsoft.EntityFrameworkCore
@inject IDbContextFactory<NorthwindContext> NorthwindContextFactory
@implements IDisposable
<DxGrid Data="GridDataSource"
ShowGroupPanel="true"
CustomGroup="Grid_CustomGroup"
CustomizeGroupValueDisplayText="Grid_CustomizeGroupValueDisplayText">
<Columns>
<DxGridDataColumn FieldName="ProductName" />
<DxGridDataColumn FieldName="Country" />
<DxGridDataColumn FieldName="OrderDate"
DisplayFormat="d" />
<DxGridDataColumn FieldName="UnitPrice"
DisplayFormat="c"
GroupIndex="0"
GroupInterval="GridColumnGroupInterval.Custom" />
<DxGridDataColumn FieldName="Quantity" />
</Columns>
</DxGrid>
@code {
object GridDataSource { get; set; }
NorthwindContext Northwind { get; set; }
protected override void OnInitialized() {
Northwind = NorthwindContextFactory.CreateDbContext();
GridDataSource = Northwind.Invoices
.ToList();
}
void Grid_CustomGroup(GridCustomGroupEventArgs e) {
if(e.FieldName == "UnitPrice") {
e.SameGroup = Grid_CompareColumnValues(e.Value1, e.Value2) == 0;
e.Handled = true;
}
}
int Grid_CompareColumnValues(object value1, object value2) {
double val1 = Math.Floor(Convert.ToDouble(value1) / 10);
double val2 = Math.Floor(Convert.ToDouble(value2) / 10);
var res = System.Collections.Comparer.Default.Compare(val1, val2);
if(res < 0)
res = -1;
else if(res > 0)
res = 1;
if(res == 0 || (val1 > 9 && val2 > 9))
res = 0;
return res;
}
void Grid_CustomizeGroupValueDisplayText(GridCustomizeGroupValueDisplayTextEventArgs e) {
if(e.FieldName == "UnitPrice") {
double val = Math.Floor(Convert.ToDouble(e.Value) / 10);
string displayText = string.Format("{0:c} - {1:c} ", val * 10, (val + 1) * 10);
if(val > 9)
displayText = string.Format(">= {0:c} ", 100);
e.DisplayText = displayText;
}
}
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<Category> Categories { get; set; }
public virtual DbSet<Customer> Customers { get; set; }
public virtual DbSet<Invoice> Invoices { get; set; }
public virtual DbSet<Order> Orders { get; set; }
public virtual DbSet<OrderDetail> OrderDetails { get; set; }
public virtual DbSet<Product> Products { get; set; }
public virtual DbSet<Shipper> Shippers { get; set; }
public virtual DbSet<Supplier> Suppliers { 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<Category>(entity => {
entity.HasIndex(e => e.CategoryName, "CategoryName");
entity.Property(e => e.CategoryId).HasColumnName("CategoryID");
entity.Property(e => e.CategoryName)
.IsRequired()
.HasMaxLength(15);
entity.Property(e => e.Description).HasColumnType("ntext");
entity.Property(e => e.Picture).HasColumnType("image");
});
modelBuilder.Entity<Customer>(entity => {
entity.HasIndex(e => e.City, "City");
entity.HasIndex(e => e.CompanyName, "CompanyName");
entity.HasIndex(e => e.PostalCode, "PostalCode");
entity.HasIndex(e => e.Region, "Region");
entity.Property(e => e.CustomerId)
.HasMaxLength(5)
.HasColumnName("CustomerID")
.IsFixedLength(true);
entity.Property(e => e.Address).HasMaxLength(60);
entity.Property(e => e.City).HasMaxLength(15);
entity.Property(e => e.CompanyName)
.IsRequired()
.HasMaxLength(40);
entity.Property(e => e.ContactName).HasMaxLength(30);
entity.Property(e => e.ContactTitle).HasMaxLength(30);
entity.Property(e => e.Country).HasMaxLength(15);
entity.Property(e => e.Fax).HasMaxLength(24);
entity.Property(e => e.Phone).HasMaxLength(24);
entity.Property(e => e.PostalCode).HasMaxLength(10);
entity.Property(e => e.Region).HasMaxLength(15);
});
modelBuilder.Entity<Invoice>(entity => {
entity.HasNoKey();
entity.ToView("Invoices");
entity.Property(e => e.Address).HasMaxLength(60);
entity.Property(e => e.City).HasMaxLength(15);
entity.Property(e => e.Country).HasMaxLength(15);
entity.Property(e => e.CustomerId)
.HasMaxLength(5)
.HasColumnName("CustomerID")
.IsFixedLength(true);
entity.Property(e => e.CustomerName)
.IsRequired()
.HasMaxLength(40);
entity.Property(e => e.ExtendedPrice).HasColumnType("money");
entity.Property(e => e.Freight).HasColumnType("money");
entity.Property(e => e.OrderDate).HasColumnType("datetime");
entity.Property(e => e.OrderId).HasColumnName("OrderID");
entity.Property(e => e.PostalCode).HasMaxLength(10);
entity.Property(e => e.ProductId).HasColumnName("ProductID");
entity.Property(e => e.ProductName)
.IsRequired()
.HasMaxLength(40);
entity.Property(e => e.Region).HasMaxLength(15);
entity.Property(e => e.RequiredDate).HasColumnType("datetime");
entity.Property(e => e.Salesperson)
.IsRequired()
.HasMaxLength(31);
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");
entity.Property(e => e.ShipperName)
.IsRequired()
.HasMaxLength(40);
entity.Property(e => e.UnitPrice).HasColumnType("money");
});
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");
entity.HasOne(d => d.Customer)
.WithMany(p => p.Orders)
.HasForeignKey(d => d.CustomerId)
.HasConstraintName("FK_Orders_Customers");
entity.HasOne(d => d.ShipViaNavigation)
.WithMany(p => p.Orders)
.HasForeignKey(d => d.ShipVia)
.HasConstraintName("FK_Orders_Shippers");
});
modelBuilder.Entity<OrderDetail>(entity => {
entity.HasKey(e => new { e.OrderId, e.ProductId })
.HasName("PK_Order_Details");
entity.ToTable("Order Details");
entity.HasIndex(e => e.OrderId, "OrderID");
entity.HasIndex(e => e.OrderId, "OrdersOrder_Details");
entity.HasIndex(e => e.ProductId, "ProductID");
entity.HasIndex(e => e.ProductId, "ProductsOrder_Details");
entity.Property(e => e.OrderId).HasColumnName("OrderID");
entity.Property(e => e.ProductId).HasColumnName("ProductID");
entity.Property(e => e.Quantity).HasDefaultValueSql("((1))");
entity.Property(e => e.UnitPrice).HasColumnType("money");
entity.HasOne(d => d.Order)
.WithMany(p => p.OrderDetails)
.HasForeignKey(d => d.OrderId)
.OnDelete(DeleteBehavior.ClientSetNull)
.HasConstraintName("FK_Order_Details_Orders");
entity.HasOne(d => d.Product)
.WithMany(p => p.OrderDetails)
.HasForeignKey(d => d.ProductId)
.OnDelete(DeleteBehavior.ClientSetNull)
.HasConstraintName("FK_Order_Details_Products");
});
modelBuilder.Entity<Product>(entity => {
entity.HasIndex(e => e.CategoryId, "CategoriesProducts");
entity.HasIndex(e => e.CategoryId, "CategoryID");
entity.HasIndex(e => e.ProductName, "ProductName");
entity.HasIndex(e => e.SupplierId, "SupplierID");
entity.HasIndex(e => e.SupplierId, "SuppliersProducts");
entity.Property(e => e.ProductId).HasColumnName("ProductID");
entity.Property(e => e.CategoryId).HasColumnName("CategoryID");
entity.Property(e => e.ProductName)
.IsRequired()
.HasMaxLength(40);
entity.Property(e => e.QuantityPerUnit).HasMaxLength(20);
entity.Property(e => e.ReorderLevel).HasDefaultValueSql("((0))");
entity.Property(e => e.SupplierId).HasColumnName("SupplierID");
entity.Property(e => e.UnitPrice)
.HasColumnType("money")
.HasDefaultValueSql("((0))");
entity.Property(e => e.UnitsInStock).HasDefaultValueSql("((0))");
entity.Property(e => e.UnitsOnOrder).HasDefaultValueSql("((0))");
entity.HasOne(d => d.Category)
.WithMany(p => p.Products)
.HasForeignKey(d => d.CategoryId)
.HasConstraintName("FK_Products_Categories");
entity.HasOne(d => d.Supplier)
.WithMany(p => p.Products)
.HasForeignKey(d => d.SupplierId)
.HasConstraintName("FK_Products_Suppliers");
});
modelBuilder.Entity<Shipper>(entity => {
entity.Property(e => e.ShipperId).HasColumnName("ShipperID");
entity.Property(e => e.CompanyName)
.IsRequired()
.HasMaxLength(40);
entity.Property(e => e.Phone).HasMaxLength(24);
});
modelBuilder.Entity<Supplier>(entity => {
entity.HasIndex(e => e.CompanyName, "CompanyName");
entity.HasIndex(e => e.PostalCode, "PostalCode");
entity.Property(e => e.SupplierId).HasColumnName("SupplierID");
entity.Property(e => e.Address).HasMaxLength(60);
entity.Property(e => e.City).HasMaxLength(15);
entity.Property(e => e.CompanyName)
.IsRequired()
.HasMaxLength(40);
entity.Property(e => e.ContactName).HasMaxLength(30);
entity.Property(e => e.ContactTitle).HasMaxLength(30);
entity.Property(e => e.Country).HasMaxLength(15);
entity.Property(e => e.Fax).HasMaxLength(24);
entity.Property(e => e.HomePage).HasColumnType("ntext");
entity.Property(e => e.Phone).HasMaxLength(24);
entity.Property(e => e.PostalCode).HasMaxLength(10);
entity.Property(e => e.Region).HasMaxLength(15);
});
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);
}
}
using Microsoft.EntityFrameworkCore;
// ...
builder.Services.AddDbContextFactory<NorthwindContext>((sp, options) => {
var env = sp.GetRequiredService<IWebHostEnvironment>();
var dbPath = Path.Combine(env.ContentRootPath, "Northwind-5e44b51f.mdf");
options.UseSqlServer("Server=(localdb)\\MSSQLLocalDB;Integrated Security=true;AttachDbFileName=" + dbPath);
});
Run Demo: Grid - Custom Grouping
Watch Video: Grid - Group Data
For more information about data grouping in the Grid component, refer to the following topic: Group Data in Blazor Grid.
See Also