DxListBox<TData, TValue>.DataAsync Property
Specifies an asynchronous function that returns List Box data.
Namespace: DevExpress.Blazor
Assembly: DevExpress.Blazor.v23.2.dll
NuGet Package: DevExpress.Blazor
Declaration
[Parameter]
public Func<CancellationToken, Task<IEnumerable<TData>>> DataAsync { get; set; }
Property Value
Type | Description |
---|---|
Func<CancellationToken, Task<IEnumerable<TData>>> | A function that returns List Box data. |
Remarks
Use the DataAsync
property to bind the List Box to a strongly typed collection that is loaded asynchronously (for instance, from an HTTP request). This property allows you to prevent the page with the List Box from excessive re-rendering.
This property specifies an asynchronous function that returns a Task<IEnumerable<T>>
object and accepts a CancellationToken object as a parameter. An exception occurs if you declare the function with an incorrect signature.
@using System.Threading;
@using System.Threading.Tasks;
<DxListBox DataAsync="@GetDataAsync" @bind-Values="@Values"></DxListBox>
@code {
IEnumerable<string> Cities = new List<string>() {
"London",
"Berlin",
"Paris",
};
IEnumerable<string> Values { get; set; }
public Task<IEnumerable<string>> GetDataAsync(CancellationToken ct = default) {
return Task.FromResult(Cities);
}
}
If you bind the List Box to a data collection that stores custom objects (IEnumerable<CustomType>
), override the object’s Equals and GetHashCode methods. Otherwise, the List Box items are populated with CustomType.ToString() values.
@using BlazorApp.Data
<DxListBox DataAsync="@Staff.GetDataAsync"
@bind-Values="@Values"
TextFieldName="@nameof(Person.Text)">
</DxListBox>
@code {
IEnumerable<Person> Values { get; set; } = Staff.DataSource.Take(2);
}
Use the Data property if a strongly typed collection is loaded synchronously. Use the CustomData property if your data is stored on a remote service and is loaded through a Web API.