Class ListBoxEvents<TValue, TItem>

Declares the set of event callbacks exposed by SfListBox<TValue, TItem> for handling filtering, selection, drag-and-drop, creation, and more.

Inheritance

System.Object

ListBoxEvents<TValue, TItem>

Namespace: Syncfusion.Blazor.DropDowns

Assembly: Syncfusion.Blazor.dll

Syntax

public class ListBoxEvents<TValue, TItem> : OwningComponentBase

Type Parameters

Name	Description
TValue	The type used to represent selected item values (e.g., string[] or int).
TItem	The data type for items displayed in the ListBox (e.g., an entity or simple value).

Remarks

Use these events to customize data requests, selection logic, UI feedback, and integration scenarios for SfListBox<TValue, TItem>.

Examples

This example demonstrates how to listen for creation, value changes, and filtering events in a ListBox:

<SfListBox @ref="ListBoxObj" DataSource="@vehicleData" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
    <ListBoxEvents TValue="string[]" Created="OnCreated" ValueChange="OnValueChange" Filtering="OnFiltering"></ListBoxEvents>
</SfListBox>
@code {
    SfListBox<string[], ListItem> ListBoxObj;
    public List<ListItem> vehicleData = new List<ListItem> {
        new ListItem { Text = "Hennessey Venom", ID = "List-01" },
        new ListItem { Text = "Bugatti Chiron", ID = "List-02" },
        new ListItem { Text = "Bugatti Veyron Super Sport", ID = "List-03" }
    };
    private Task OnCreated(object args) => ListBoxObj.SelectItemsAsync(Value, true);
    private void OnValueChange(ListBoxChangeEventArgs<string[], ListItem> args) { /* React to selection changes */ }
    private void OnFiltering(FilteringEventArgs args) { /* Custom filtering logic */ }
    public class ListItem { public string Text {get;set;} public string ID {get;set;} }
}

Constructors

ListBoxEvents()

Declaration

public ListBoxEvents()

Properties

Created

Raised when the ListBox is fully initialized and ready for interaction.

Declaration

public EventCallback<object> Created { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<System.Object>

Examples

private Task OnCreated(object args) { /* Additional setup after creation */ }

Destroyed

Raised when the ListBox is destroyed, letting you clean up state or subscriptions.

Declaration

public EventCallback<object> Destroyed { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<System.Object>

DragStart

Triggered before starting to drag an item, enabling custom logic or cancellation.

Declaration

public EventCallback<DragEventArgs<TItem>> DragStart { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<DragEventArgs<TItem>>

Remarks

Available only when AllowDragAndDrop is true.

Dropped

Triggered after successful drop operation to let you respond to or process item movement.

Declaration

public EventCallback<DropEventArgs<TItem>> Dropped { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<DropEventArgs<TItem>>

Remarks

Available only when AllowDragAndDrop is true.

Filtering

Raised whenever the user enters text to filter or search ListBox items.

Declaration

public EventCallback<FilteringEventArgs> Filtering { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<FilteringEventArgs>

Remarks

Available only when AllowFiltering is true.

Examples

private void OnFiltering(FilteringEventArgs args) {
    // Customize query for dynamic filtering
}

ListBoxItemKeyDown

Triggered when performing a keydown action in a ListBox item (e.g. for advanced keyboard handling).

Declaration

public EventCallback<ListBoxKeyDownEventArgs> ListBoxItemKeyDown { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<ListBoxKeyDownEventArgs>

OnActionBegin

Invoked before fetching data from a remote server in the SfListBox<TValue, TItem>. Allows you to customize request parameters or cancel the request.

Declaration

public EventCallback<ActionBeginEventArgs> OnActionBegin { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<ActionBeginEventArgs>

OnActionComplete

Invoked after data has been successfully fetched from a remote server.

Declaration

public EventCallback<ActionCompleteEventArgs<TItem>> OnActionComplete { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<ActionCompleteEventArgs<TItem>>

OnActionFailure

Triggered when a data fetch from the server fails. Use to log or display errors.

Declaration

public EventCallback<object> OnActionFailure { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<System.Object>

OnDrop

Triggered before dropping items onto the ListBox, allowing cancellation or custom drop behavior.

Declaration

public EventCallback<DropEventArgs<TItem>> OnDrop { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<DropEventArgs<TItem>>

Remarks

Available only when AllowDragAndDrop is true.

OnItemRender

Occurs before rendering each item in the ListBox, giving you the chance to customize item content or appearance.

Declaration

public EventCallback<BeforeItemRenderEventArgs<TItem>> OnItemRender { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<BeforeItemRenderEventArgs<TItem>>

ValueChange

Triggered when the selected value(s) of the ListBox change.

Declaration

public EventCallback<ListBoxChangeEventArgs<TValue, TItem>> ValueChange { get; set; }

Property Value

Type
Microsoft.AspNetCore.Components.EventCallback<ListBoxChangeEventArgs<TValue, TItem>>

Methods

Dispose(Boolean)

Declaration

protected override void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing

OnInitializedAsync()

Declaration

protected override Task OnInitializedAsync()

Returns

Type
System.Threading.Tasks.Task