Class ComboBoxModel

Represents the configuration model for the Syncfusion ComboBox component, providing data binding, filtering, event handling, and UI customization options.

Inheritance

System.Object

ComboBoxModel

Namespace: Syncfusion.Blazor.DropDowns

Assembly: Syncfusion.Blazor.dll

Syntax

public class ComboBoxModel : Object

Remarks

ComboBoxModel is used to control the behavior, appearance, and data operations of Syncfusion ComboBox.

Examples

<SfComboBox TValue="string" DataSource="@(new List<string>{"Apple", "Banana"})" Placeholder="Pick fruit">
    <ComboBoxEvents OnChange="@(args => ComboChanged(args))" />
</SfComboBox>

<SfComboBox TValue="string" DataSource="@(new List<string>{"Apple", "Banana"})" Placeholder="Pick a fruit">
    <ComboBoxEvents OnChange="@(args => ComboChanged(args))" />
</SfComboBox>

Constructors

ComboBoxModel()

Declaration

public ComboBoxModel()

Properties

ActionBegin

Gets or sets the event data raised when a remote data fetch is initiated for the ComboBox component.

Declaration

public ActionBeginEventArgs ActionBegin { get; set; }

Property Value

Type	Description
ActionBeginEventArgs	An `ActionBeginEventArgs` instance with event information for fetch initiation.

Remarks

This event allows custom logic or modification of ComboBox queries prior to data retrieval. For more details, see ActionBeginEventArgs.

Examples

Refer to ActionBeginEventArgs for use-cases and structure.

ActionComplete

Gets or sets the event data for when remote data fetching completes successfully.

Declaration

public ActionCompleteEventArgs ActionComplete { get; set; }

Property Value

Type	Description
ActionCompleteEventArgs	An `ActionCompleteEventArgs` instance containing successful completion details.

Remarks

This event fires after a remote fetch or asynchronous data call finishes. Use it to manage post-fetch logic. See ActionCompleteEventArgs for more info.

Examples

Utilize for end-to-end APIs when asynchronous requests resolve.

ActionFailure

Gets or sets an event callback triggered when a data fetch request from a remote server fails.

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` for error/failure handling logic.

Remarks

Attach error handlers to respond gracefully if a remote fetch fails for any reason.

Examples

@code {
    void OnFailure(object args) { /* Handle fetch error */ }
}

AllowCustom

Gets or sets a value controlling whether the ComboBox allows the user to create values not present in the provided data source.

Declaration

public bool AllowCustom { get; set; }

Property Value

Type	Description
System.Boolean	`true` to enable user-generated custom values; `false` to restrict to known list values. Default is `true`.

Remarks

Use to implement tagging, flexible data entry, or user-driven value creation. If false, ComboBox is strictly list-bound.

Examples

Enable for flexible forms where entry is not list-limited.

Autofill

Gets or sets whether ComboBox auto-suggests and pre-selects the first matched item as user types.

Declaration

public bool Autofill { get; set; }

Property Value

Type	Description
System.Boolean	`true` for autofill, `false` for manual selection. Default is `false`.

Remarks

This makes keyboard selection rapid and can guide users to most likely matches for search-heavy lists.

Examples

Perfect for quick lookups or catalogues where primary entry is predictable.

BeforeOpen

Gets or sets the event arguments raised right before the ComboBox popup opens.

Declaration

public BeforeOpenEventArgs BeforeOpen { get; set; }

Property Value

Type	Description
BeforeOpenEventArgs	A `BeforeOpenEventArgs` instance representing event data before popup rendering.

Remarks

Use this event to conditionally cancel, or dynamically style/position, the dropdown popup on open.

Examples

Leverage BeforeOpenEventArgs to set Cancel = true if a popup should not display.

Blur

Gets or sets the event callback triggered when focus leaves the ComboBox (a blur event).

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` triggered on ComboBox blur; commonly used for focus validation.

Remarks

This event is triggered when the input focus is lost, which is commonly used for validation or UI cleanup operations.

Examples

Listen for blur to validate user input or reset error states.

Change

Gets or sets an event callback triggered when an item is selected or the model value changes via user input.

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` for ComboBox value or selection changes.

Remarks

This callback is fired whenever the selection changes, allowing configuration like cascading, custom validation, or responding to user input. See the OnChange event for full details.

Examples

@code {
    void ComboChanged(object args) {
        // Your change logic
    }
}

Close

Gets or sets the event callback invoked when the ComboBox popup is closed.

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` called after the popup closes.

Remarks

Use this event to handle UI cleanup, trigger notifications, or persist popup dismissals.

Examples

Detect when users finish selection by closing the popup.

Created

Gets or sets the event callback raised after the ComboBox component is fully initialized and created.

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` for post-creation logic or composition.

Remarks

This event is ideal for external initialization logic, dynamic data loading, or applying global state to a just-constructed ComboBox.

Examples

Listen for ComboBox creation to trigger data binding or analytics.

CustomValueSpecifier

Gets or sets an event callback triggered when the ComboBox user sets or accepts a custom value not found in the available list.

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` for custom value logic events.

Remarks

Implement this to support tagging or creation of new user-defined options directly in ComboBox UI.

Examples

See event data for details on providing custom entry support.

DataBound

Gets or sets the arguments provided when the ComboBox data binding completes.

Declaration

public DataBoundEventArgs DataBound { get; set; }

Property Value

Type	Description
DataBoundEventArgs	A `DataBoundEventArgs` instance with completion and status information.

Remarks

Bind this property to react after successful data load into the ComboBox.

Examples

Monitor for loading completion using DataBoundEventArgs.

DebounceDelay

Gets or sets the number of milliseconds to wait before filtering after user input (if filtering is enabled).

Declaration

public int DebounceDelay { get; set; }

Property Value

Type	Description
System.Int32	An `int` indicating the debounce delay in milliseconds. Default is 300 ms.

Remarks

This affects filtering responsiveness; delays reduce network/API load for remote data calls. Lower values increase UI reactivity; higher values help throttle calls with slow endpoints.

Examples

Set to 500 for slow API filtering, 100 for instant local search.

Destroyed

Gets or sets an event callback triggered when the ComboBox component is disposed (destroyed/unmounted).

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` for destruction or cleanup scenarios.

Remarks

Attach analytics, release resources, or execute teardown code on component destroy.

Examples

Release resources on Destroyed event.

EnableVirtualization

Gets or sets whether virtualization is enabled for ComboBox, improving performance in large data sets (1000+ items).

Declaration

public bool EnableVirtualization { get; set; }

Property Value

Type	Description
System.Boolean	`true` enables virtualization/chunked rendering; `false` disables for standard UI. Default is `false`.

Remarks

Turn on for scenarios where large volumes of data would otherwise degrade performance. Combines well with virtual scroll and lazy data load.

Examples

Use large-data ComboBox for geographical selection with virtualization.

Filtering

Gets or sets the event callback triggered on each character typed in ComboBox (filter/search event).

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` for real-time filter, search, or lookup logic.

Remarks

Leverage this callback for dynamic queries, external data API integration, or custom filtering implementations.

Examples

Monitor typing for filtering and dynamic API calls.

Focus

Gets or sets an event callback called when the ComboBox receives focus.

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` for focus/activation UI logic.

Remarks

Useful for applying contextual highlighting or input cues as users navigate with keyboard or screen readers.

Examples

Emphasize the control or show UI aids on focus.

Open

Gets or sets an event callback triggered when the ComboBox popup opens (shows dropdown list).

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` called when the popup is displayed.

Remarks

This event is used for analytics, lazy loading, or providing interactive guidance when a user expands the ComboBox.

Examples

@code {
    void OnPopupOpen(object args) {
        // React to dropdown showing
    }
}

Select

Gets or sets an event callback triggered when an item in the popup is selected by user action (mouse, tap, or keyboard selection).

Declaration

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

Property Value

Type	Description
Microsoft.AspNetCore.Components.EventCallback<System.Object>	An `EventCallback<object>` for item selection notifications.

Remarks

Respond to user selection and update models or UI accordingly.

Examples

@code {
    void OnSelect(object args) {
        // Handle item selection
    }
}

ShowClearButton

Gets or sets whether the ComboBox clear button is shown, allowing users to quickly remove value selections.

Declaration

public bool ShowClearButton { get; set; }

Property Value

Type	Description
System.Boolean	`true` enables the visible clear button, `false` disables. Default is `true`.

Remarks

Clicking the clear button resets Value, Text, and Index properties. Recommended for improved user experience and quick resets.

Examples

Best for forms with single-choice rapid switching requirements.