DxGrid.SelectedDataItemsChanged Event
In multiple selection mode, fires when the selection in the Grid changes.
Namespace: DevExpress.Blazor
Assembly:
DevExpress.Blazor.v21.2.dll
NuGet Package:
DevExpress.Blazor
Declaration
[Parameter]
public EventCallback<IReadOnlyList<object>> SelectedDataItemsChanged { get; set; }
Parameters
Type |
Description |
IReadOnlyList<Object> |
A collection that stores information about selection changes.
|
The SelectedDataItemsChanged
event fires each time the SelectedDataItems property changes. This property specifies data items that correspond to the selected Grid rows in multiple selection mode.
The event is handled automatically when you use two-way data binding for the SelectedDataItemsChanged
property (@bind-SelectedDataItemsChanged
).
Handle this event to respond to selection changes in a custom way. In the event handler, you can get data items that were added to and removed from selection. To do this, cast the event handler’s parameter to the IGridSelectionChanges interface and use the SelectedDataItems and DeselectedDataItems properties.
The following example handles the SelectedDataItemsChanged
event to display information about selection changes:
@using Microsoft.EntityFrameworkCore
@inject IDbContextFactory<NorthwindContext> NorthwindContextFactory
@implements IDisposable
<DxGrid Data="GridDataSource"
AllowSelectRowByClick="true"
SelectedDataItems="@SelectedDataItems"
SelectedDataItemsChanged="OnSelectedDataItemsChanged"
KeyFieldName="ProductId">
<Columns>
<DxGridDataColumn FieldName="ProductName" />
<DxGridDataColumn FieldName="UnitPrice" />
<DxGridDataColumn FieldName="QuantityPerUnit" />
<DxGridDataColumn FieldName="UnitsInStock" />
</Columns>
</DxGrid>
<br />
<div><b>Added to selection</b>: @SelectedItemsInfo</div>
<div><b>Removed from selection</b>: @DeselectedItemsInfo</div>
@code {
IEnumerable<object> GridDataSource { get; set; }
NorthwindContext Northwind { get; set; }
IReadOnlyList<object> SelectedDataItems { get; set; }
string SelectedItemsInfo { get; set; }
string DeselectedItemsInfo { get; set; }
protected override void OnInitialized() {
Northwind = NorthwindContextFactory.CreateDbContext();
GridDataSource = Northwind.Products
.ToList();
SelectedDataItems = GridDataSource.Skip(1).Take(2).ToList();
}
void OnSelectedDataItemsChanged(IReadOnlyList<object> newSelection) {
if (newSelection is IGridSelectionChanges changes) {
SelectedItemsInfo = string.Join("; ", changes.SelectedDataItems
.Cast<Product>()
.Select(p => p.ProductName)
);
DeselectedItemsInfo = string.Join("; ", changes.DeselectedDataItems
.Cast<Product>()
.Select(p => p.ProductName)
);
}
SelectedDataItems = newSelection;
}
public void Dispose() {
Northwind?.Dispose();
}
}
using System;
using System.Collections.Generic;
#nullable disable
namespace Grid.Northwind {
public partial class Product {
public Product() {
OrderDetails = new HashSet<OrderDetail>();
}
public int ProductId { get; set; }
public string ProductName { get; set; }
public int? SupplierId { get; set; }
public int? CategoryId { get; set; }
public string QuantityPerUnit { get; set; }
public decimal? UnitPrice { get; set; }
public short? UnitsInStock { get; set; }
public short? UnitsOnOrder { get; set; }
public short? ReorderLevel { get; set; }
public bool Discontinued { get; set; }
public virtual Category Category { get; set; }
public virtual Supplier Supplier { get; set; }
public virtual ICollection<OrderDetail> OrderDetails { get; set; }
}
}
using Microsoft.EntityFrameworkCore;
#nullable disable
namespace Grid.Northwind {
public partial class NorthwindContext : DbContext {
public NorthwindContext(DbContextOptions<NorthwindContext> options)
: base(options) {
}
// ...
public virtual DbSet<Product> Products { 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.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");
});
// ...
OnModelCreatingPartial(modelBuilder);
}
partial void OnModelCreatingPartial(ModelBuilder modelBuilder);
}
}
using Microsoft.EntityFrameworkCore;
// ...
public class Startup {
// ...
public void ConfigureServices(IServiceCollection services) {
// ...
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);
});
}
// ...
}
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);
});
See Also