Data Binding in Blazor MultiSelect Dropdown Component
1 Nov 202424 minutes to read
The MultiSelect loads the data either from the local data sources or remote data services. Using the DataSource property, bind the local data or using the DataManager, bind the remote data.
- TItem - Specifies the type of the datasource of the multiselect component.
Binding local data
The MultiSelect loads the data from local data sources through the DataSource property. It supports the data type of Array of primitive type, Array of object, List of primitive type,List of object, Observable Collection, ExpandoObject, DynamicObject.
@using Syncfusion.Blazor.DropDowns
@foreach (var SelectedValue in MultiVal)
{
<p>MultiSelect value is:<strong>@SelectedValue</strong></p>
}
<SfMultiSelect Placeholder="e.g. Australia" @bind-Value="@MultiVal" DataSource="@Countries">
<MultiSelectFieldSettings Value="Name"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public string[] MultiVal { get; set; } = new string[] { };
public class Country
{
public string Name { get; set; }
public string Code { get; set; }
}
List<Country> Countries = new List<Country>
{
new Country() { Name = "Australia", Code = "AU" },
new Country() { Name = "Bermuda", Code = "BM" },
new Country() { Name = "Canada", Code = "CA" },
new Country() { Name = "Cameroon", Code = "CM" },
};
}
DataBound event
The DataBound event triggers when the data source is populated in the popup list.
@using Syncfusion.Blazor.DropDowns
<SfMultiSelect TItem="GameFields" TValue="string[]" DataSource="@Games">
<MultiSelectEvents TItem="GameFields" TValue="string[]" DataBound="@DataBoundHandler"></MultiSelectEvents>
<MultiSelectFieldSettings Text="Text" Value="ID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public class GameFields
{
public string ID { get; set; }
public string Text { get; set; }
}
private List<GameFields> Games = new List<GameFields>() {
new GameFields(){ ID= "Game1", Text= "American Football" },
new GameFields(){ ID= "Game2", Text= "Badminton" },
new GameFields(){ ID= "Game3", Text= "Basketball" },
new GameFields(){ ID= "Game4", Text= "Cricket" },
};
private void DataBoundHandler(DataBoundEventArgs args)
{
// Here you can customize your code
}
}Primitive type
Bind the data to the MultiSelect as an array or list of the string, int, double and bool type items.
The following code demonstrates array of string values to the MultiSelect component.
@using Syncfusion.Blazor.DropDowns
<SfMultiSelect TValue="string[]" TItem="string" Placeholder="Select a game" DataSource="@data" @bind-Value="MyItem" Width="300px"></SfMultiSelect>
@code{
List<string> data = new List<string>() {"One", "Two", "Three"};
public string[] MyItem { get; set; } = ["Two"];
}
The following code demonstrates array of integer values to the DropDownList component.
@using Syncfusion.Blazor.DropDowns
<SfMultiSelect TValue="int[]?" TItem="int?" Placeholder="Select a game" DataSource="@data" @bind-Value="MyItem" Width="300px"></SfMultiSelect>
@code{
List<int?> data = new List<int?>() { 100, 200, 300 };
public int[]? MyItem { get; set; } = [300];
}
Complex data type
The MultiSelect can generate its list items through an array of complex data. For this, the appropriate columns should be mapped to the Fields property.
In the following example, Code.ID column and Country.CountryID column from complex data have been mapped to the Value field and Text field, respectively.
@using Syncfusion.Blazor.DropDowns
<SfMultiSelect TValue="string[]" TItem="Complex" Placeholder="e.g. Select a country" DataSource="@LocalData">
<MultiSelectFieldSettings Text="Country.CountryID" Value="Code.ID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public List<Complex> LocalData { get; set; } = new Complex().GetData();
public class Code
{
public string ID { get; set; }
}
public class Country
{
public string CountryID { get; set; }
}
public class Complex
{
public Country Country { get; set; }
public Code Code { get; set; }
public List<Complex> GetData() {
List<Complex>Data = new List<Complex>();
Data.Add(new Complex() { Country = new Country() { CountryID = "Australia" }, Code = new Code() { ID = "AU" } });
Data.Add(new Complex() { Country = new Country() { CountryID = "Bermuda" }, Code = new Code() { ID = "BM" } });
Data.Add(new Complex() { Country = new Country() { CountryID = "Canada" }, Code = new Code() { ID = "CA" } });
Data.Add(new Complex() { Country = new Country() { CountryID = "Cameroon" }, Code = new Code() { ID = "CM" } });
Data.Add(new Complex() { Country = new Country() { CountryID = "Denmark" }, Code = new Code() { ID = "DK" } });
Data.Add(new Complex() { Country = new Country() { CountryID = "France" }, Code = new Code() { ID = "FR" } });
return Data;
}
}
}
Expando object binding
Bind the ExpandoObject data to the MultiSelect component. In the following example, the ExpandoObject is bound to the collection of vehicles data.
@using Syncfusion.Blazor.DropDowns
@using System.Dynamic
<SfMultiSelect TItem="ExpandoObject" TValue="string[]" PopupHeight="230px" Placeholder="Select a vehicle" DataSource="@VehicleData">
<MultiSelectFieldSettings Text="Text" Value="ID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code{
public List<ExpandoObject> VehicleData { get; set; } = new List<ExpandoObject>();
protected override void OnInitialized()
{
VehicleData = Enumerable.Range(1, 15).Select((x) =>
{
dynamic d = new ExpandoObject();
d.ID = (1000 + x).ToString();
d.Text = (new string[] { "Hennessey Venom", "Bugatti Chiron", "Bugatti Veyron Super Sport", "SSC Ultimate Aero", "Koenigsegg CCR", "McLaren F1", "Aston Martin One- 77", "Jaguar XJ220", "McLaren P1", "Ferrari LaFerrari", "Mahindra Jaguar", "Hyundai Toyota", "Jeep Volkswagen", "Tata Maruti Suzuki", "Audi Mercedes Benz" }[x - 1]);
return d;
}).Cast<ExpandoObject>().ToList<ExpandoObject>();
}
}
Observable collection binding
Bind the ObservableCollection data to the MultiSelect component. In the following example, the Observable Data is bound to a collection of colors data.
@using Syncfusion.Blazor.DropDowns
@using System.Collections.ObjectModel;
<SfMultiSelect TValue="string[]" TItem="Colors" PopupHeight="230px" Placeholder="Select a color" DataSource="@ColorsData">
<MultiSelectFieldSettings Text="Color" Value="Code"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public class Colors
{
public string Code { get; set; }
public string Color { get; set; }
}
private ObservableCollection<Colors> ColorsData = new ObservableCollection<Colors>()
{
new Colors() { Color = "Chocolate", Code = "#75523C" },
new Colors() { Color = "CadetBlue", Code = "#3B8289" },
new Colors() { Color = "DarkOrange", Code = "#FF843D" },
new Colors() { Color = "DarkRed", Code = "#CA3832"},
new Colors() { Color = "Fuchsia", Code = "#D44FA3" },
new Colors() { Color = "HotPink", Code = "#F23F82" },
new Colors() { Color = "Indigo", Code = "#2F5D81" },
new Colors() { Color = "LimeGreen", Code = "#4CD242" },
new Colors() { Color = "OrangeRed", Code = "#FE2A00" },
new Colors() { Color = "Tomato", Code = "#FF745C" },
new Colors() { Color = "Brown", Code = "#A52A2A" },
new Colors() { Color = "Maroon", Code = "#800000" },
new Colors() { Color = "Green", Code = "#008000" },
new Colors() { Color = "Pink", Code = "#FFC0CB" },
new Colors() { Color = "Purple", Code = "#800080" }
};
}
Dynamic object binding
Bind the DynamicObject data to the MultiSelect component. In the following example, the DynamicObject is bound to the collection of customer data.
@using Syncfusion.Blazor.DropDowns
@using System.Dynamic
<SfMultiSelect TValue="string[]" TItem="DynamicDictionary" Placeholder="Select a name" DataSource="@Orders">
<MultiSelectFieldSettings Text="CustomerName" Value="CustomerName"></MultiSelectFieldSettings>
</SfMultiSelect>
@code{
public List<DynamicDictionary> Orders = new List<DynamicDictionary>() { };
protected override void OnInitialized()
{
Orders = Enumerable.Range(1, 15).Select((x) =>
{
dynamic d = new DynamicDictionary();
d.OrderID = 1000 + x;
d.CustomerName = (new string[] { "Nancy", "Andrew", "Janet", "Margaret", "Steven", "Michael", "Robert", "Anne", "Nige", "Fuller", "Dodsworth", "Leverling", "Callahan", "Suyama", "Davolio" }[x - 1]);
return d;
}).Cast<DynamicDictionary>().ToList<DynamicDictionary>();
}
public class DynamicDictionary : System.Dynamic.DynamicObject
{
Dictionary<string, object> dictionary = new Dictionary<string, object>();
public override bool TryGetMember(GetMemberBinder binder, out object result)
{
string name = binder.Name;
return dictionary.TryGetValue(name, out result);
}
public override bool TrySetMember(SetMemberBinder binder, object value)
{
dictionary[binder.Name] = value;
return true;
}
//The GetDynamicMemberNames method of DynamicObject class must be overridden and return the property names to perform data operation and editing while using DynamicObject.
public override System.Collections.Generic.IEnumerable<string> GetDynamicMemberNames()
{
return this.dictionary?.Keys;
}
}
}
Enum data binding
Convert the Enum data into a list of strings and bind it to the DataSource property of the SfMultiSelect component to bind Enum types to the MultiSelect Dropdown component.
@using Syncfusion.Blazor.DropDowns
<SfMultiSelect TValue="List<string>" TItem="string" Placeholder="Select a color" DataSource="@MultiSelectDataSource"
@bind-Value="SelectedValues">
<MultiSelectFieldSettings Value="Value" Text="Text"></MultiSelectFieldSettings>
</SfMultiSelect>
@if (SelectedValues != null)
{
<p>Selected Colors: @string.Join(", ", SelectedValues)</p>
}
@code {
public enum Color
{
Red,
Blue,
Green,
Yellow
}
public class EnumModel
{
public Color Value { get; set; }
public string Text { get; set; }
}
private List<string> MultiSelectDataSource { get; set; } = new List<string>();
private List<string> SelectedValues { get; set; }
protected override void OnInitialized()
{
MultiSelectDataSource = Enum.GetNames(typeof(Color)).ToList();
SelectedValues = new List<string> { Enum.GetName(typeof(Color), 2) };
}
}
ValueTuple data binding
Bind the ValueTuple data to the MultiSelect component. The following code helps you to get a string value from the enumeration data by using ValueTuple.
@using Syncfusion.Blazor.DropDowns;
<SfMultiSelect TItem="(DayOfWeek, string)" Width="250px" TValue="DayOfWeek[]"
DataSource="@(Enum.GetValues<DayOfWeek>().Select(e => (e, e.ToString())))">
<MultiSelectFieldSettings Value="Item1" Text="Item2" />
</SfMultiSelect>
Binding remote data
The MultiSelect supports the retrieval of data from the remote data services with the help of the DataManager control. The Query property is used to fetch data from the database and bind it to the MultiSelect.
- DataManager.Url - Defines the service endpoint to fetch data.
- DataManager.Adaptor - Defines the adaptor option. By default, the ODataAdaptor is used for remote binding. The adaptor is responsible for processing responses and requests from or to the service endpoint.
- Syncfusion.Blazor.Data package provides some predefined adaptors that are designed to interact with particular service endpoints.
OnActionBegin event
The OnActionBegin event triggers before fetching data from the remote server.
@using Syncfusion.Blazor.DropDowns
@using Syncfusion.Blazor.Data
<SfMultiSelect TValue="string" TItem="OrderDetails" Query="@RemoteDataQuery">
<SfDataManager Url="https://js.syncfusion.com/demos/ejServices/Wcf/Northwind.svc/Orders" CrossDomain="true" Adaptor="Syncfusion.Blazor.Adaptors.ODataAdaptor"></SfDataManager>
<MultiSelectEvents TValue="string" TItem="OrderDetails" OnActionBegin="@OnActionBeginhandler"></MultiSelectEvents>
<MultiSelectFieldSettings Text="CustomerID" Value="CustomerID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public Query RemoteDataQuery = new Query().Select(new List<string> { "CustomerID" }).Take(6).RequiresCount();
public class OrderDetails
{
public int? OrderID { get; set; }
public string CustomerID { get; set; }
public int? EmployeeID { get; set; }
public double? Freight { get; set; }
public string ShipCity { get; set; }
public bool Verified { get; set; }
public DateTime? OrderDate { get; set; }
public string ShipName { get; set; }
public string ShipCountry { get; set; }
public DateTime? ShippedDate { get; set; }
public string ShipAddress { get; set; }
}
private void OnActionBeginhandler(ActionBeginEventArgs args)
{
// Here you can customize your code
}
}OnActionComplete event
The OnActionComplete event triggers after data is fetched successfully from the remote server.
@using Syncfusion.Blazor.DropDowns
@using Syncfusion.Blazor.Data
<SfMultiSelect TValue="string" TItem="OrderDetails" Query="@RemoteDataQuery">
<SfDataManager Url="https://js.syncfusion.com/demos/ejServices/Wcf/Northwind.svc/Orders" CrossDomain="true" Adaptor="Syncfusion.Blazor.Adaptors.ODataAdaptor"></SfDataManager>
<MultiSelectEvents TValue="string" TItem="OrderDetails" OnActionComplete="@OnActionCompletehandler"></MultiSelectEvents>
<MultiSelectFieldSettings Text="CustomerID" Value="CustomerID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public Query RemoteDataQuery = new Query().Select(new List<string> { "CustomerID" }).Take(6).RequiresCount();
public class OrderDetails
{
public int? OrderID { get; set; }
public string CustomerID { get; set; }
public int? EmployeeID { get; set; }
public double? Freight { get; set; }
public string ShipCity { get; set; }
public bool Verified { get; set; }
public DateTime? OrderDate { get; set; }
public string ShipName { get; set; }
public string ShipCountry { get; set; }
public DateTime? ShippedDate { get; set; }
public string ShipAddress { get; set; }
}
private void OnActionCompletehandler(ActionCompleteEventArgs<OrderDetails> args)
{
// Here you can customize your code
}
}OnActionFailure event
The OnActionFailure event triggers when the data fetch request from the remote server fails.
@using Syncfusion.Blazor.DropDowns
@using Syncfusion.Blazor.Data
<SfMultiSelect TValue="string" TItem="OrderDetails" Query="@RemoteDataQuery">
<SfDataManager Url="https://js.syncfusion.com/demos/ejServices/Wcf/Northwind.svc/Orders" CrossDomain="true" Adaptor="Syncfusion.Blazor.Adaptors.ODataAdaptor"></SfDataManager>
<MultiSelectEvents TValue="string" TItem="OrderDetails" OnActionFailure="@OnActionFailurehandler"></MultiSelectEvents>
<MultiSelectFieldSettings Text="CustomerID" Value="CustomerID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public Query RemoteDataQuery = new Query().Select(new List<string> { "CustomerID" }).Take(6).RequiresCount();
public class OrderDetails
{
public int? OrderID { get; set; }
public string CustomerID { get; set; }
public int? EmployeeID { get; set; }
public double? Freight { get; set; }
public string ShipCity { get; set; }
public bool Verified { get; set; }
public DateTime? OrderDate { get; set; }
public string ShipName { get; set; }
public string ShipCountry { get; set; }
public DateTime? ShippedDate { get; set; }
public string ShipAddress { get; set; }
}
private void OnActionFailurehandler(Exception args)
{
// Here you can customize your code
}
}OData v4 services
The OData v4 Adaptor provides the ability to consume and manipulate data from OData v4 services. The following sample displays the first six customer details from Customers table of the Northwind Data Service.
@using Syncfusion.Blazor.Data
@using Syncfusion.Blazor.DropDowns
<SfMultiSelect TValue="string[]" TItem="OrderDetails" Placeholder="Select a customer" Query="@Query">
<SfDataManager Url="https://services.odata.org/V4/Northwind/Northwind.svc/Orders" Adaptor="Adaptors.ODataV4Adaptor" CrossDomain=true></SfDataManager>
<MultiSelectFieldSettings Text="CustomerID" Value="OrderID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public Query Query = new Query().Select(new List<string> { "CustomerID", "OrderID" }).Take(6).RequiresCount();
public class OrderDetails
{
public int? OrderID { get; set; }
public string CustomerID { get; set; }
public int? EmployeeID { get; set; }
public double? Freight { get; set; }
public string ShipCity { get; set; }
public bool Verified { get; set; }
public DateTime? OrderDate { get; set; }
public string ShipName { get; set; }
public string ShipCountry { get; set; }
public DateTime? ShippedDate { get; set; }
public string ShipAddress { get; set; }
}
}
Web API adaptor
The Web API Adaptor is used to interact with Web API created under OData standards. The WebApiAdaptor is extended from the ODataAdaptor. Hence to use the WebApiAdaptor, the endpoint should understand the OData formatted queries sent along with the request.
@using Syncfusion.Blazor.Data
@using Syncfusion.Blazor
@using Syncfusion.Blazor.DropDowns
<SfMultiSelect TValue="string[]" Placeholder="Select a Employee" Query="@Query">
<SfDataManager Url="https://ej2services.syncfusion.com/production/web-services/api/Employees" Adaptor="Adaptors.WebApiAdaptor" CrossDomain=true></SfDataManager>
<MultiSelectFieldSettings Text="FirstName" Value="EmployeeID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public Query Query = new Query();
public class EmployeeData
{
public int EmployeeID { get; set; }
public string FirstName { get; set; }
public string Designation { get; set; }
public string Country { get; set; }
}
}
Custom adaptor
The SfDataManager has custom adaptor support which allows to perform manual operations on the data. This can be utilized for implementing custom data binding and editing operations in the MultiSelect component.
For implementing custom data binding in MultiSelect, the DataAdaptor class is used. This abstract class acts as a base class for the custom adaptor.
The DataAdaptor abstract class has both synchronous and asynchronous method signatures which can be overridden in the custom adaptor.
public abstract class DataAdaptor
{
/// <summary>
/// Performs data Read operation synchronously.
/// </summary>
public virtual object Read(DataManagerRequest dataManagerRequest, string key = null)
/// <summary>
/// Performs data Read operation asynchronously.
/// </summary>
public virtual Task<object> ReadAsync(DataManagerRequest dataManagerRequest, string key = null)
}The custom data binding can be performed in the MultiSelect component by providing the custom adaptor class and overriding the Read or ReadAsync method of the DataAdaptor abstract class.
The following sample code demonstrates implementing custom data binding using custom adaptor.
<SfMultiSelect TValue="string[]" TItem="Orders">
<SfDataManager AdaptorInstance="@typeof(CustomAdaptor)" Adaptor="Adaptors.CustomAdaptor"></SfDataManager>
<MultiSelectFieldSettings Value="CustomerID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code{
public class Orders
{
public Orders() { }
public Orders(int OrderID, string CustomerID)
{
this.OrderID = OrderID;
this.CustomerID = CustomerID;
}
public int OrderID { get; set; }
public string CustomerID { get; set; }
}
public class CustomAdaptor : DataAdaptor
{
public static List<OrdersDetails> order = OrdersDetails.GetAllRecords();
public override object Read(DataManagerRequest dm, string key = null)
{
IEnumerable<OrdersDetails> DataSource = order;
if (dm.Search != null && dm.Search.Count > 0)
{
DataSource = DataOperations.PerformSearching(DataSource, dm.Search); //Search
}
if (dm.Sorted != null && dm.Sorted.Count > 0) //Sorting
{
DataSource = DataOperations.PerformSorting(DataSource, dm.Sorted);
}
if (dm.Where != null && dm.Where.Count > 0) //Filtering
{
DataSource = DataOperations.PerformFiltering(DataSource, dm.Where, dm.Where[0].Operator);
}
int count = DataSource.Cast<OrdersDetails>().Count();
if (dm.Skip != 0)
{
DataSource = DataOperations.PerformSkip(DataSource, dm.Skip); //Paging
}
if (dm.Take != 0)
{
DataSource = DataOperations.PerformTake(DataSource, dm.Take);
}
return dm.RequiresCounts ? new DataResult() { Result = DataSource, Count = count } : (object)DataSource;
}
}
}Offline mode
To avoid post back for every action, set the MultiSelect to load all data on initialization and make the actions process in client-side. To enable this behaviour, use the Offline property of DataManager.
The following example is for remote data binding and enabled offline mode.
@using Syncfusion.Blazor
@using Syncfusion.Blazor.Data
@using Syncfusion.Blazor.DropDowns
<SfMultiSelect TValue="string[]" TItem="EmployeeData" Placeholder="Select a Employee" Query="@Query">
<SfDataManager Url="https://ej2services.syncfusion.com/production/web-services/api/Employees" Adaptor="Adaptors.WebApiAdaptor" CrossDomain=true Offline=true></SfDataManager>
<MultiSelectFieldSettings Text="FirstName" Value="EmployeeID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public Query Query = new Query();
public class EmployeeData
{
public int EmployeeID { get; set; }
public string FirstName { get; set; }
public string Designation { get; set; }
public string Country { get; set; }
}
}
Entity Framework
Follow these steps to consume data from the Entity Framework in the MultiSelect component.
Create DBContext class
The first step is to create a DBContext class called OrderContext to connect to a Microsoft SQL Server database.
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using EFDropDown.Shared.Models;
namespace EFDropDown.Shared.DataAccess
{
public class OrderContext : DbContext
{
public virtual DbSet<Shared.Models.Order> Orders { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
if (!optionsBuilder.IsConfigured)
{
optionsBuilder.UseSqlServer(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=D:\Blazor\DropDownList\EFDropDown\Shared\App_Data\NORTHWND.MDF;Integrated Security=True;Connect Timeout=30");
}
}
}
}Create data access layer to perform data operation
Now, create a class named OrderDataAccessLayer, which act as data access layer for retrieving the records from the database table.
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using EFDropDown.Shared.Models;
namespace EFDropDown.Shared.DataAccess
{
public class OrderDataAccessLayer
{
OrderContext db = new OrderContext();
//To Get all Orders details
public DbSet<Order> GetAllOrders()
{
try
{
return db.Orders;
}
catch
{
throw;
}
}
}
}Creating web API controller
A Web API Controller has to be created which allows MultiSelect directly to consume data from the Entity framework.
using EFDropDown.Shared.DataAccess;
using EFDropDown.Shared.Models;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Web;
using Microsoft.AspNetCore.Http;
namespace EFDropDown.Controllers
{
[Route("api/[controller]")]
[ApiController]
//TreeGrid
public class DefaultController : ControllerBase
{
OrderDataAccessLayer db = new OrderDataAccessLayer();
[HttpGet]
public object Get()
{
IQueryable<Order> data = db.GetAllOrders().AsQueryable();
var count = data.Count();
var queryString = Request.Query;
if (queryString.Keys.Contains("$inlinecount"))
{
StringValues Skip;
StringValues Take;
int skip = (queryString.TryGetValue("$skip", out Skip)) ? Convert.ToInt32(Skip[0]) : 0;
int top = (queryString.TryGetValue("$top", out Take)) ? Convert.ToInt32(Take[0]) : data.Count();
return new { Items = data.Skip(skip).Take(top), Count = count };
}
else
{
return data;
}
}
}
}Configure MultiSelect component using Web API adaptor
Now, configure the MultiSelect using the SfDataManager to interact with the created Web API and consume the data appropriately. To interact with web API, use the WebApiAdaptor.
@using Syncfusion.Blazor
@using Syncfusion.Blazor.Data
@using Syncfusion.Blazor.DropDowns
<SfMultiSelect TValue="string[]" TItem="Order" Placeholder="Select a Country">
<SfDataManager Url="api/Default" Adaptor="Adaptors.WebApiAdaptor" CrossDomain="true"></SfDataManager>
<MultiSelectFieldSettings Text="ShipCountry" Value="OrderID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code{
public class Order
{
public int? OrderID { get; set; }
public string[] ShipCountry { get; set; }
}
}Adding new items
Add the new item in the popup with the help of AddItemsAsync public method. This method will add a mentioned item in the MultiSelect popup without affecting the data source items.
<div>
<SfMultiSelect @ref="multiselectObj" TValue="string[]" TItem="Games" Width="300px" Placeholder="Select a game" DataSource="@LocalData">
<MultiSelectFieldSettings Value="ID" Text="Game"></MultiSelectFieldSettings>
</SfMultiSelect>
</div>
<div>
<SfButton Content="Click to add a new item" OnClick="OnBtnClick"></SfButton>
</div>
@code {
SfMultiSelect<string[], Games> multiselectObj;
public class Games
{
public string ID { get; set; }
public string Game { get; set; }
}
List<Games> LocalData = new List<Games> {
new Games() { ID= "Game1", Game= "American Football" },
new Games() { ID= "Game2", Game= "Badminton" },
new Games() { ID= "Game3", Game= "Basketball" },
new Games() { ID= "Game4", Game= "Cricket" },
new Games() { ID= "Game5", Game= "Football" },
new Games() { ID= "Game6", Game= "Golf" },
new Games() { ID= "Game7", Game= "Hockey" },
new Games() { ID= "Game8", Game= "Rugby"},
new Games() { ID= "Game9", Game= "Snooker" },
};
public async Task OnBtnClick()
{
await this.multiselectObj.AddItemsAsync(new List<Games> { new Games() { ID = "Game11", Game = "Tennis" } });
}
}
Customizing the Change Event
MultiSelect component by default fires the Change event when the component loses focus. However, if you want the Change event to be fired every time a value is selected or removed, disable the EnabledChangeOnBlur property. This will make the Change event be fired on every value selection and removal instead of just when the component loses focus. The default value of EnableChangeOnBlur is true.
@using Syncfusion.Blazor.DropDowns;
<SfMultiSelect TValue="string[]" TItem="Games" Placeholder="Favorite Sports" DataSource="@LocalData" EnableChangeOnBlur="@EnableChangeOnBlur">
<MultiSelectEvents TItem="Games" TValue="string[]" ValueChange="@ValueChangeHandler"></MultiSelectEvents>
<MultiSelectFieldSettings Text="Text" Value="ID"></MultiSelectFieldSettings>
</SfMultiSelect>
@code {
public class Games
{
public string ID { get; set; }
public string Text { get; set; }
}
List<Games> LocalData = new List<Games> {
new Games() { ID= "Game1", Text= "American Football" },
new Games() { ID= "Game2", Text= "Badminton" },
new Games() { ID= "Game3", Text= "Basketball" },
new Games() { ID= "Game4", Text= "Cricket" },
new Games() { ID= "Game5", Text= "Football" },
new Games() { ID= "Game6", Text= "Golf" },
new Games() { ID= "Game7", Text= "Hockey" },
new Games() { ID= "Game8", Text= "Rugby"},
new Games() { ID= "Game9", Text= "Snooker" },
new Games() { ID= "Game10", Text= "Tennis"},
};
public bool EnableChangeOnBlur { get; set; } = false;
private void ValueChangeHandler()
{
// Here you can customize your code
}
}Get Data by value
You can retrieve the selected value from the dropdown list by using the GetDataByValue(TValue) method through an instance of the dropdown list. You can bind the click event of a button to the GetDataByValue(TValue) method of the dropdown list instance. When the button is clicked, it will trigger the GetDataByValue(TValue) method on the dropdown list and return the selected value.
@using Syncfusion.Blazor.DropDowns;
<div class=button>
<button @onclick="GetDataByValue">Button</button>
</div>
<div class=content>
<SfMultiSelect @ref="MultiSelectObj" TValue="string[]" TItem="Games" Placeholder="Favorite Sports" DataSource="@LocalData" ShowDropDownIcon="true" @bind-Value="@GameValue">
<MultiSelectFieldSettings Text="Text" Value="ID"></MultiSelectFieldSettings>
</SfMultiSelect>
</div>
@code {
SfMultiSelect<string[],Games> MultiSelectObj;
public class Games
{
public string ID { get; set; }
public string Text { get; set; }
}
List<Games> LocalData = new List<Games> {
new Games() { ID= "Game1", Text= "American Football" },
new Games() { ID= "Game2", Text= "Badminton" },
new Games() { ID= "Game3", Text= "Basketball" },
new Games() { ID= "Game4", Text= "Cricket" },
new Games() { ID= "Game5", Text= "Football" },
new Games() { ID= "Game6", Text= "Golf" },
new Games() { ID= "Game7", Text= "Hockey" },
new Games() { ID= "Game8", Text= "Rugby"},
new Games() { ID= "Game9", Text= "Snooker" },
new Games() { ID= "Game10", Text= "Tennis"},
};
public string[] GameValue { get; set; } = { "Game5"};
public async void GetDataByValue()
{
var val = this.MultiSelectObj.Value;
var Data = await this.MultiSelectObj.GetDataByValueAsync(val);
Console.WriteLine (Data[0].ID.ToString());
Console.WriteLine (Data[0].Text.ToString());
}
}
<style>
.content{
margin-top: 5px;
}
</style>Get List Item
You can retrieve the list items from the dropdown list by using the GetItemsAsync() method through an instance of the dropdown list. You can bind the click event of a button to the GetItemsAsync() method of the dropdown list instance. When the button is clicked, it will trigger the GetItemsAsync() method on the dropdown list and return the list items
@using Syncfusion.Blazor.DropDowns;
<div class=button>
<button @onclick="GetItems">Button</button>
</div>
<div class=content>
<SfMultiSelect @ref="MultiSelectObj" TValue="string[]" TItem="Games" Placeholder="Favorite Sports" DataSource="@LocalData" ShowDropDownIcon="true" @bind-Value="@GameValue" FilterType="FilterType.StartsWith">
<MultiSelectFieldSettings Text="Text" Value="ID"></MultiSelectFieldSettings>
</SfMultiSelect>
</div>
@code {
SfMultiSelect<string[],Games> MultiSelectObj;
public class Games
{
public string ID { get; set; }
public string Text { get; set; }
}
List<Games> LocalData = new List<Games> {
new Games() { ID= "Game1", Text= "American Football" },
new Games() { ID= "Game2", Text= "Badminton" },
new Games() { ID= "Game3", Text= "Basketball" },
new Games() { ID= "Game4", Text= "Cricket" },
new Games() { ID= "Game5", Text= "Football" },
new Games() { ID= "Game6", Text= "Golf" },
new Games() { ID= "Game7", Text= "Hockey" },
new Games() { ID= "Game8", Text= "Rugby"},
new Games() { ID= "Game9", Text= "Snooker" },
new Games() { ID= "Game10", Text= "Tennis"},
};
public string[] GameValue { get; set; } = { "Game5"};
public async Task GetItems () {
IEnumerable<Games> Items = await this.MultiSelectObj.GetItemsAsync();
foreach(var listItem in Items)
{
Console.WriteLine (listItem.ID);
Console.WriteLine (listItem.Text);
}
}
}
<style>
.content{
margin-top: 5px;
}
</style>