Class SfListBox<TValue, TItem>

The SfListBox<TValue, TItem> control is a Syncfusion Blazor component for single and multi-selection of list items with support for search, group, drag-and-drop, reordering, and customizable toolbar UI.

Inheritance
System.Object
SfBaseComponent
SfDataBoundComponent
SfDropDownBase<TItem>
SfListBox<TValue, TItem>
Inherited Members
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.CheckAndResetCache()
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.DataId
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.GetDataByText(System.String, System.String)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.GetFilteringSkeletonCount()
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.GetPageQuery(Syncfusion.Blazor.Data.Query, System.Int32, System.Int32)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.GetPropertyValue(System.Object, System.String)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.GetStyles()
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.GetTakeValue()
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.GetVirtualTrackHeight()
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.HighlightSearch(System.String, System.String, System.Boolean, Syncfusion.Blazor.DropDowns.FilterType)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.IncrementalSearch(System.String, System.Collections.Generic.IEnumerable<TItem>, System.Nullable<System.Int32>, System.Boolean)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.IsActionFailed
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.IsMinimalData
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.ItemData
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.ListDataSource
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.MainData
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.RefreshVirtualIndices()
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.RenderItemsAsync(System.Collections.Generic.IEnumerable<TItem>)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.RenderListItemsAsync(System.Collections.Generic.IEnumerable<TItem>, Syncfusion.Blazor.DropDowns.FieldSettingsModel, Syncfusion.Blazor.Data.Query)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.Search(System.String, System.Collections.Generic.IEnumerable<TItem>, System.String, System.Boolean)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.SetListDataAsync(System.Collections.Generic.IEnumerable<TItem>, Syncfusion.Blazor.DropDowns.FieldSettingsModel, Syncfusion.Blazor.Data.Query)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.TotalCount
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.UpdateListHeight(System.Double)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.VirtualAction
Namespace: Syncfusion.Blazor.DropDowns
Assembly: Syncfusion.Blazor.dll
Syntax
public class SfListBox<TValue, TItem> : SfDropDownBase<TItem>, IListBox
Type Parameters
Name Description
TValue

The value type of the selected or bound items (usually string, int, or an array).
TItem

The data model type for each selectable item (commonly a POCO).
Remarks

Use SfListBox<TValue, TItem> for display and selection of complex, interactive list content. Advanced configuration enables features such as multi-column templates, item grouping, toolbar actions, filtering, and more for enterprise UI scenarios.

This partial class contains private or internal constants; see other parts of the class for public API.

Examples

This example shows a ListBox configured for text display with selection binding:

<SfListBox Value="@value" DataSource="@vehicleData" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
</SfListBox>
@code {
    private string[] value = new[] { "List-01" };
    private 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" }
    };
    public class ListItem { public string Text { get; set; } public string ID { get; set; } }
}

The following example demonstrates how to use the ListBox component in a Blazor application for vehicle selection:

<SfListBox Value="@value" DataSource="@vehicleData" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
</SfListBox>
@code {
    private string[] value = new string[] { "List-01" };
    private 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" }
    };
    public class ListItem
    {
        public string Text { get; set; }
        public string ID { get; set; }
    }
}

Usage example:

<SfListBox Value="@value" DataSource="@vehicleData" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
</SfListBox>

This example shows basic property binding:

<SfListBox Value="@value" DataSource="@vehicleData" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
</SfListBox>

See example usage in the Syncfusion ListBox component documentation or in the class summary of main SfListBox<TValue, TItem>.

Constructors

SfListBox()

Declaration
public SfListBox()

Properties

AllowDragAndDrop

Gets or sets a value indicating whether drag-and-drop functionality is allowed in the SfListBox<TValue, TItem>.

Declaration
public bool AllowDragAndDrop { get; set; }
Property Value
Type Description
System.Boolean

true if drag-and-drop functionality is allowed; otherwise, false. The default value is false.
Remarks

The Scope property is used to perform drag and drop between different SfListBox<TValue, TItem>.

AllowFiltering

Gets or sets a value indicating whether filtering is allowed in the SfListBox<TValue, TItem>.

Declaration
public bool AllowFiltering { get; set; }
Property Value
Type Description
System.Boolean

true if filtering is allowed; otherwise, false. The default value is false.
Remarks

The FilterBarPlaceholder property is used to show placeholder on the filter bar.

ComponentName

Gets the unique component name for rendering and diagnostics.

Declaration
protected override string ComponentName { get; set; }
Property Value
Type
System.String
Overrides
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.ComponentName

CssClass

Gets or sets the class/multiple classes separated by a space for the SfListBox<TValue, TItem> component.

Declaration
public string CssClass { get; set; }
Property Value
Type Description
System.String

The CSS class string to customize the appearance of the SfListBox<TValue, TItem>. The default value is an empty string.

Enabled

Gets or sets a value indicating whether the SfListBox<TValue, TItem> is enabled to interact with it.

Declaration
public bool Enabled { get; set; }
Property Value
Type Description
System.Boolean

true if the control is enabled; otherwise, false. The default value is true.

EnablePersistence

Gets or sets a value indicating whether the component's state should be persisted across postbacks.

Declaration
public bool EnablePersistence { get; set; }
Property Value
Type Description
System.Boolean

true if the component's state should be persisted; otherwise, false. The default value is false.
Remarks

The Value property is used to persist the component's state.

EnableRtl

Gets or sets a value indicating whether the control should display in Right-to-Left (RTL) direction.

Declaration
public bool EnableRtl { get; set; }
Property Value
Type Description
System.Boolean

true if the control should display in RTL direction; otherwise, false. The default value is false.

FilterBarPlaceholder

Gets or sets the placeholder text for the filter bar in the SfListBox<TValue, TItem>.

Declaration
public string FilterBarPlaceholder { get; set; }
Property Value
Type Description
System.String

The string value that represents the placeholder text for the filter bar in the SfListBox<TValue, TItem>. The default value is an empty string.
Remarks

This property will take into effect once the AllowFiltering property is true.

Examples

The below code example, showcases a filter bar place holder support in the SfListBox<TValue, TItem>.

<SfListBox Value="@value" DataSource="@vehicleData" AllowFiltering="True" FilterBarPlaceHolder="Enter a string to filter" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
</SfListBox>
@code{
    private string[] value= new string[] { "List-01"};
    private 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"}
    }
    public class ListItem
    {
        public string Text { get; set; }
        public string ID { get; set; }
     }
}

Height

Gets or sets a value that indicates the height of the SfListBox<TValue, TItem>.

Declaration
public string Height { get; set; }
Property Value
Type Description
System.String

A string value that represents the height of the SfListBox<TValue, TItem>. The default value is "". If the value is not specified, then the height will be calculated based on the entire list item's height.
Remarks

To add the suffix 'px' to the value if the height is fixed, for instance, '200px'. To add the suffix '%' to the value if the height is responsive, for instance, '200%'.

HtmlAttributes

Gets or sets the additional attributes to be applied to the SfListBox<TValue, TItem> container element.

Declaration
public Dictionary<string, object> HtmlAttributes { get; set; }
Property Value
Type Description
System.Collections.Generic.Dictionary<System.String, System.Object>

A collection of attributes to be added to the SfListBox<TValue, TItem> container element.
Remarks

Additional attributes can be added by specifying as inline attributes or by specifying the @attributes directive.

MaximumSelectionLength

Gets or sets the maximum length of items that can be selected in the SfListBox<TValue, TItem>.

Declaration
public int MaximumSelectionLength { get; set; }
Property Value
Type Description
System.Int32

An integer value that represents the maximum selection length. The default value is 500.
Remarks

Based on the limitation, list selection will be prevented.

Readonly

Gets or sets a value indicating whether the SfListBox<TValue, TItem> is in read-only mode or not.

Declaration
public bool Readonly { get; set; }
Property Value
Type Description
System.Boolean

true if the control is in read-only mode; otherwise, false. The default is false.

Scope

Gets or sets a value that indicates the scope of the SfListBox<TValue, TItem>.

Declaration
public string Scope { get; set; }
Property Value
Type Description
System.String

A string value that represents the scope of the SfListBox<TValue, TItem>.
Remarks

The drag and drop operation and the toolbar interactions performed based on the Scope value. The AllowDragAndDrop and ListBoxToolbarSettings is used to enable drag and drop as well as toolbar interactions in the SfListBox<TValue, TItem>.

Examples

The below code example, showcases drag and drop support with scope property in the SfListBox<TValue, TItem>.

<SfListBox Scope="@scope" AllowDragAndDrop="true" DataSource="@vehicleData1" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
    <ListBoxToolbarSettings Items="@items"></ListBoxToolbarSettings>
</SfListBox>
<SfListBox Scope="@scope" AllowDragAndDrop="true" DataSource="@vehicleData2" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
</SfListBox>
@code{
    private string scope= "combined-list";
    private string[] items = new string[] { "MoveUp", "MoveDown", "MoveTo", "MoveFrom", "MoveAllTo", "MoveAllFrom" };
    private List<ListItem> vehicleData1 = 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 List<ListItem> vehicleData2 = new List<ListItem>{
        new ListItem { Text = "SSC Ultimate Aero", ID = "List-04" },
        new ListItem { Text = "Koenigsegg CCR", ID = "List-05" },
        new ListItem { Text = "McLaren F1", ID = "List-06" }
    }
    public class ListItem
    {
        public string Text { get; set; }
        public string ID { get; set; }
     }
}

Value

Gets or sets a value that indicates the selected items in the SfListBox<TValue, TItem>.

Declaration
public TValue Value { get; set; }
Property Value
Type
TValue

ValueChanged

An event callback that is triggered when the value of the component changes.

Declaration
public EventCallback<TValue> ValueChanged { get; set; }
Property Value
Type Description
Microsoft.AspNetCore.Components.EventCallback<TValue>

An event callback function.
Remarks

By using this event and the ValueExpression property, two-way binding can be achieved instead of using @bind-Value.

Examples

The below code example, showcases a SfListBox<TValue, TItem>.

<SfListBox ValueExpression="@(() => value )" ValueChanged="@((string[] v) => value = v)" DataSource="@vehicleData" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
</SfListBox>
@code{
    private string[] value= new string[] { "List-01"};
    private 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"}
    }
    public class ListItem
    {
        public string Text { get; set; }
        public string ID { get; set; }
     }
}

ValueExpression

Gets or sets a lambda expression that identifies the bound value of Value property.

Declaration
public Expression<Func<TValue>> ValueExpression { get; set; }
Property Value
Type Description
System.Linq.Expressions.Expression<System.Func<TValue>>

The lambda expression that identifies the value bound to the Value property.
Remarks

By using this property and the ValueChanged event, two-way binding can be achieved instead of using @bind-Value.

Examples

The below code example, showcases a basic SfListBox<TValue, TItem>.

<SfListBox ValueExpression="@(() => value )" ValueChanged="@((string[] v) => value = v)" DataSource="@vehicleData" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
</SfListBox>
@code{
    private string[] value= new string[] { "List-01"};
    private 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"}
    }
    public class ListItem
    {
        public string Text { get; set; }
        public string ID { get; set; }
     }
}

Methods

ActionBeginAsync(IEnumerable<TItem>, Query)

Triggers the ActionBegin event callback with current data source and query before data operations (load, filter, etc).

Declaration
protected override Task<ActionBeginEventArgs> ActionBeginAsync(IEnumerable<TItem> dataSource, Query query = null)
Parameters
Type Name Description
System.Collections.Generic.IEnumerable<TItem> dataSource

The data set about to be processed.
Query query

The query to be executed (if any).
Returns
Type Description
System.Threading.Tasks.Task<ActionBeginEventArgs>

A System.Threading.Tasks.Task resolving to the event args for the operation.
Overrides
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.ActionBeginAsync(System.Collections.Generic.IEnumerable<TItem>, Syncfusion.Blazor.Data.Query)

ActionCompleteAsync(IEnumerable<TItem>, Query)

Triggers the ActionComplete event after data has loaded, filtered, or changed, updating the ListBox’s display to reflect new results.

Declaration
protected override Task ActionCompleteAsync(IEnumerable<TItem> dataSource, Query query = null)
Parameters
Type Name Description
System.Collections.Generic.IEnumerable<TItem> dataSource

The final processed data collection.
Query query

The query executed (if any).
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the post-update logic.
Overrides
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.ActionCompleteAsync(System.Collections.Generic.IEnumerable<TItem>, Syncfusion.Blazor.Data.Query)

ActionFailureAsync(Object)

Called when an asynchronous action fails (such as a data source or query failure), triggering any failure event callbacks.

Declaration
protected override Task ActionFailureAsync(object arguments)
Parameters
Type Name Description
System.Object arguments

The failure state or error object.
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task for the async failure handling operation.
Overrides
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.ActionFailureAsync(System.Object)

BuildRenderTree(RenderTreeBuilder)

Declaration
protected override void BuildRenderTree(RenderTreeBuilder __builder)
Parameters
Type Name Description
Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder

Dispose(Boolean)

Disposes the ListBox control and resources, called by the Blazor framework when removed.

Declaration
protected override void Dispose(bool disposing)
Parameters
Type Name Description
System.Boolean disposing

True to dispose managed resources; false otherwise.
Overrides
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.Dispose(System.Boolean)

EnableItems<T>(T, Boolean)

Enables or disables an item or collection of items based on the specified items and the enable parameter in the SfListBox<TValue, TItem>.

Declaration
public void EnableItems<T>(T items, bool enable = true)
Parameters
Type Name Description
T items

Specifies the list items to be enabled or disabled. You can pass either value(TValue) or data source(TItem) collection.
System.Boolean enable

Specifies false to disable the items. By default the items will be enabled.
Type Parameters
Name
T
Examples

The below code example, showcases a EnableItems method to enable / disable the list items.

<SfListBox @ref="ListBoxObj" Value="@value" DataSource="@vehicleData" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
    <ListBoxEvents TValue="string[]" Created="created"></ListBoxEvents>
</SfListBox>
@code{
    SfListBox<string[],ListItem> ListBoxObj;
    private string[] value= new string[] { "List-01"};
    private 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"}
    }
    public string[] Value = new string[] { "Bugatti Chiron" };
    private void created()
    {
         ListBoxObj.EnableItems(Value, false);
    }
    public class ListItem
    {
        public string Text { get; set; }
        public string ID { get; set; }
     }
}

FilterAsync(IEnumerable<TItem>, Query, FieldSettingsModel)

To filter the data from given data source by using query.

Declaration
public Task FilterAsync(IEnumerable<TItem> dataSource, Query query = null, FieldSettingsModel fields = null)
Parameters
Type Name Description
System.Collections.Generic.IEnumerable<TItem> dataSource

Specifies the data source.
Query query

Specifies the query.
FieldSettingsModel fields

Specifies the fields.
Returns
Type Description
System.Threading.Tasks.Task

Task.

GetDataByValue(TValue)

Gets an item or a collection of items with type of 'TItem' that matches the specific list of values such as string[], int[] etc.

Declaration
public List<TItem> GetDataByValue(TValue dataValue)
Parameters
Type Name Description
TValue dataValue

Specifies the value(s) such as string[], int[] etc.
Returns
Type Description
System.Collections.Generic.List<TItem>

The list of items with the type of 'TItem'.

GetDataList()

Gets the collection of list items bound to the SfListBox<TValue, TItem>.

Declaration
public IEnumerable<TItem> GetDataList()
Returns
Type Description
System.Collections.Generic.IEnumerable<TItem>

The list of items with the type of 'TItem'.

GetPersistData()

Retrieves the persisted selection data for this ListBox from local storage, if available.

Declaration
protected Task<string> GetPersistData()
Returns
Type Description
System.Threading.Tasks.Task<System.String>

A System.Threading.Tasks.Task<> that resolves to the stored selection, or null if not found.

GetQuery(Query)

Builds the query used for filtering or searching within the ListBox data source, incorporating current component filter options.

Declaration
protected override Query GetQuery(Query query)
Parameters
Type Name Description
Query query

The input query from configuration or parent context.
Returns
Type Description
Query

A new or modified Query instance used to filter the data.
Overrides
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.GetQuery(Syncfusion.Blazor.Data.Query)

IsFilterMode()

Indicates whether the ListBox is currently operating in filter mode (built-in filtering enabled).

Declaration
protected override bool IsFilterMode()
Returns
Type Description
System.Boolean

true if filtering is enabled; otherwise, false.
Overrides
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.IsFilterMode()

MoveAllAsync(String, Nullable<Int32>)

Moves all the items from source SfListBox<TValue, TItem> to the destination SfListBox<TValue, TItem>.

Declaration
public Task MoveAllAsync(string scope = null, Nullable<int> index = null)
Parameters
Type Name Description
System.String scope

Specifies the scope used to identify the destination SfListBox<TValue, TItem> for the move operation.
System.Nullable<System.Int32> index

Specifies the index of the location where the moved items should be placed.
Returns
Type Description
System.Threading.Tasks.Task

A Task that represents the asynchronous operation of moving all the items. It completes when the component has finished the action.

MoveAsync(TValue, Nullable<Int32>, String)

Moves an item or the collection of items based on the specified value(s) to the destination SfListBox<TValue, TItem>.

Declaration
public Task MoveAsync(TValue values = null, Nullable<int> index = null, string scope = null)
Parameters
Type Name Description
TValue values

Specifies the value(s) to move the list of items upwards.
System.Nullable<System.Int32> index

Specifies the index of the location where the moved items should be placed.
System.String scope

Specifies the scope used to identify the destination SfListBox<TValue, TItem> for the move operation.
Returns
Type Description
System.Threading.Tasks.Task

A Task that represents the asynchronous operation of moving the items upwards. It completes when the component has finished the action.

MoveDownAsync(TValue)

Moves an item or the collection of items based on the specified value(s) to downwards in the current SfListBox<TValue, TItem>.

Declaration
public Task MoveDownAsync(TValue values = null)
Parameters
Type Name Description
TValue values

Specifies the value(s) to move the list of items downwards.
Returns
Type Description
System.Threading.Tasks.Task

A Task that represents the asynchronous operation of moving items downwards. It completes when the component has finished the action.

MoveUpAsync(TValue)

Moves an item or the collection of items based on the specified value(s) to upwards in the current SfListBox<TValue, TItem>.

Declaration
public Task MoveUpAsync(TValue values = null)
Parameters
Type Name Description
TValue values

Specifies the value(s) to move the list of items upwards.
Returns
Type Description
System.Threading.Tasks.Task

A Task that represents the asynchronous operation of moving the items upwards. It completes when the component has finished the action.

OnAfterRenderAsync(Boolean)

Runs additional setup logic after the component has rendered. Handles template rendering, field setup, and local storage persistence.

Declaration
protected override Task OnAfterRenderAsync(bool firstRender)
Parameters
Type Name Description
System.Boolean firstRender

true if this is the first component render; otherwise, false.
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the asynchronous after-render workflow.
Overrides

OnInitializedAsync()

Invoked by the Blazor framework when the component is initialized; sets up initial property states and scripts.

Declaration
protected override Task OnInitializedAsync()
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the asynchronous initialization process.
Overrides
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.OnInitializedAsync()

OnParametersSetAsync()

Called by the Blazor framework whenever component parameters are set; performs property synchronization and handles reactivity.

Declaration
protected override Task OnParametersSetAsync()
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task indicating parameter update completion.
Overrides
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.OnParametersSetAsync()

RemoveItemAsync(IEnumerable<TItem>, Nullable<Int32>)

Removes an item or collection of items from the listbox base on the given items. By default, it removes the last item, but you can also removes the item based on the index parameter.

Declaration
public Task RemoveItemAsync(IEnumerable<TItem> items = null, Nullable<int> itemIndex = null)
Parameters
Type Name Description
System.Collections.Generic.IEnumerable<TItem> items

Specifies the list of data collection to be removed.
System.Nullable<System.Int32> itemIndex

Specifies the index to remove the item from the list.
Returns
Type Description
System.Threading.Tasks.Task

A Task that represents the asynchronous operation of removing the items. It completes when the component has finished the action.

SelectAllAsync(Boolean)

Selects or deselects the entire collection of items of the SfListBox<TValue, TItem> based on the state parameter.

Declaration
public Task SelectAllAsync(bool state = true)
Parameters
Type Name Description
System.Boolean state

Set true/false to select/ unselect the entire list items.
Returns
Type Description
System.Threading.Tasks.Task

A Task that represents the asynchronous operation of selecting all the items. It completes when the component has finished the action.

SelectItemsAsync<T>(T, Boolean)

Selects or deselects the specific collection of items based on the given value(s) and the state parameters.

Declaration
public Task SelectItemsAsync<T>(T items, bool state = true)
Parameters
Type Name Description
T items

Specifies the collection items to be selected or unselected. You can pass either value(TValue) or data source(TItem) collection.
System.Boolean state

Set false to un select the items. By default the items will be selected.
Returns
Type Description
System.Threading.Tasks.Task

A Task that represents the asynchronous operation of selecting the items. It completes when the component has finished the action.
Type Parameters
Name
T
Examples

The below code example, showcases a SelectItemsAsync method.

<SfListBox @ref="ListBoxObj" Value="@value" DataSource="@vehicleData" TValue="string[]" TItem="ListItem">
    <ListBoxFieldSettings Text="Text" Value="ID"></ListBoxFieldSettings>
    <ListBoxEvents TValue="string[]" Created="created"></ListBoxEvents>
</SfListBox>
@code{
    SfListBox<string[],ListItem> ListBoxObj;
    private string[] value= new string[] { "List-01"};
    private 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"}
    }
    public string[] Value = new string[] { "Bugatti Chiron" };
    private async Task created(object args)
    {
         await ListBoxObj.SelectItemsAsync(Value, true);
    }
    public class ListItem
    {
        public string Text { get; set; }
        public string ID { get; set; }
     }
}

SetLocalStorage(String, List<String>)

Persists the specified ListBox selection to local storage using the provided key.

Declaration
protected Task SetLocalStorage(string persistId, List<string> values)
Parameters
Type Name Description
System.String persistId

Key for persistence in browser storage.
System.Collections.Generic.List<System.String> values

The values (selected items) to store.
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task for the async storage operation.