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DxListBox<TData, TValue>.CustomData Property

Specifies an asynchronous function that loads List Box data based on the specified load options.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v23.2.dll

NuGet Package: DevExpress.Blazor


public Func<DataSourceLoadOptionsBase, CancellationToken, Task<LoadResult>> CustomData { get; set; }

Property Value

Type Description
Func<DevExtreme.AspNet.Data.DataSourceLoadOptionsBase, CancellationToken, Task<DevExtreme.AspNet.Data.ResponseModel.LoadResult>>

A delegate that implements data load logic.


To bind the List Box to data that is stored on a remote service and is loaded through a Web API, assign the data type to the component’s T parameter and use the CustomData property to implement data load logic. This property specifies an asynchronous function that accepts two parameters:

In this function, you can use the ConvertToGetRequestUri and ConvertToHttpContent extension methods to generate HTTP requests with parameters based on data load options. The function should return a Task<LoadResult> object.

Note that if you use the CustomData property and virtual list render mode, the data item collection can include fake items for items that are still loading.

Implement a Controller

On a remote service, implement an API controller and create action methods that use the DevExtreme.AspNet.Data library’s DataSourceLoader class to create a LoadResult object based on load options. If you pass a DataSourceLoadOptions class instance as an argument in controller actions, add a reference to the DevExtreme.AspNet.Mvc namespace from the DevExtreme.AspNet.Core NuGet package.


@using CustomData.Data
@using DevExtreme.AspNet.Data
@using DevExtreme.AspNet.Data.ResponseModel
@using System.Threading
@using System.Threading.Tasks
@using System.Net.Http
@using System.Text.Json

<DxListBox TData="@(WebApiLookup)" 
           TextFieldName="Text" >

@code {
    [Inject] protected HttpClient Client { get; set; }

    protected Task<LoadResult> LoadCustomData(DataSourceLoadOptionsBase options, CancellationToken cancellationToken) {
        return CustomDataHelper.LoadCustomData(Client, options, cancellationToken);

ListBox CustomData

View Example: Data Editors for Blazor - Custom data binding


DevExpress.Blazor.IListBox<TData, TValue>.CustomData
See Also