Class SfMultiSelect<TValue, TItem>

Syncfusion Blazor MultiSelect dropdown control that allows selection of one or more items from a list, with advanced search and filtering capabilities.

Inheritance
System.Object
SfBaseComponent
SfDataBoundComponent
SfDropDownBase<TItem>
SfMultiSelect<TValue, TItem>
Implements
Syncfusion.Blazor.DropDowns.IVirtualList<TItem>
Inherited Members
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.ActionBeginAsync(System.Collections.Generic.IEnumerable<TItem>, Syncfusion.Blazor.Data.Query)
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.CheckAndResetCache()
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.ComponentName
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>.GetQuery(Syncfusion.Blazor.Data.Query)
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>.OnInitializedAsync()
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.OnParametersSetAsync()
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 SfMultiSelect<TValue, TItem> : SfDropDownBase<TItem>, IDropDowns, IVirtualList<TItem>
Type Parameters
Name Description
TValue

The value type for the selected item(s). Supports primitives or collection.
TItem

The type of each list item in the data source. Typically a DTO or primitive.
Remarks

Supports data-driven item rendering, customizable field mapping, filtering, virtualization, checkboxes, custom value entry, and keyboard navigation.

Examples
<SfMultiSelect TValue="string" TItem="Product" DataSource="@Products" AllowFiltering="true">
    <MultiSelectFieldSettings Text="Name" Value="Id" />
</SfMultiSelect>
@code {
    List<Product> Products = ...;
}
<SfMultiSelect TValue="string[]" TItem="Country" DataSource="@CountryList">
  <MultiSelectFieldSettings Text="Name" Value="IsoCode" />
</SfMultiSelect>
@inject SfMultiSelect<string[], Country> MyMultiSelectRef;
...
await MyMultiSelectRef.ClearAsync(); // Clear selection from code
await MyMultiSelectRef.ShowPopupAsync(); // Open the item dropdown programmatically

Constructors

SfMultiSelect()

Declaration
public SfMultiSelect()

Properties

AllowCustomValue

Gets or sets a value indicating whether the MultiSelect Dropdown component allows entering custom values.

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

true if custom values are allowed; otherwise, false.

AllowFiltering

Gets or sets a value indicating whether filtering is allowed in the MultiSelect Dropdown component.

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

true if filtering is allowed; otherwise, false.
Remarks

If the searching character does not match, the NoRecordsTemplate property value will be shown.

AllowResize

Gets or sets a value indicating whether the resizing option is enabled for the popup.

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

true if resizing is enabled, allowing the user to resize the popup by dragging its edges; otherwise, false. The default value is false.
Remarks

When AllowResize is set to true, the popup includes a resizable handle at the bottom right corner, enabling users to adjust its size. This resizing functionality can be further controlled using the OnResizeStart and OnResizeStop events to monitor or restrict resizing behavior.

Examples




@code {
    private void HandleResizeStart(object args) {
        Console.WriteLine("Resize started.");
    }

    private void HandleResizeStop(object args) {
        Console.WriteLine("Resize stopped.");
    }
}

CssClass

Gets or sets a CSS class string to customize the appearance of the SfMultiSelect<TValue, TItem> component.

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

Accepts a CSS class string separated by space to customize the appearance. The default value is String.Empty.

DebounceDelay

Gets or sets the debounce delay in milliseconds for filtering the items in the SfMultiSelect<TValue, TItem> component. The debounce delay represents the time delay between the last keystroke and the filtering operation. This delay helps reduce the frequency of data filtering while typing. The default value is 300 milliseconds.

The DebounceDelay property only takes effect when the AllowFiltering property is set to true.

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

An integer representing the debounce delay in milliseconds. The default value is 300.
Remarks

The DebounceDelay property helps optimize performance by delaying the filtering operation until the user has stopped typing for the specified delay duration. To work with the default filtering scenario, the user needs to set the DebounceDelay value to zero.

Examples

The following example demonstrates how to set the DebounceDelay property to 500 milliseconds.

DelimiterChar

Gets or sets the delimiter character used to separate selected items in the MultiSelect Dropdown component.

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

The delimiter character used for item separation. The default value is ",".

EnableChangeOnBlur

Gets or sets a value indicating whether the value change should occur on blur for the MultiSelect Dropdown component.

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

true if value change occurs on blur; otherwise, false. The default value is true.

EnableCloseOnSelect

Gets or sets a value indicating whether the dropdown should close automatically after selecting an item in the MultiSelect Dropdown component.

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

true if the dropdown should close on select; otherwise, false.

Enabled

Gets or sets a value indicating whether the MultiSelect Dropdown component is enabled.

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

true if the MultiSelect Dropdown component is enabled; otherwise, false. The default value is true.

EnableGroupCheckBox

Gets or sets a value indicating whether the group checkbox is enabled in the MultiSelect Dropdown component.

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

true if the group checkbox is enabled; otherwise, false.
Remarks

This property allows you to render checkbox for group headers and to select all the grouped items at once.

EnablePersistence

Gets or sets a value indicating whether the component's state should be persisted between page reloads.

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

true if persistence is enabled; otherwise, false.

EnableRtl

Gets or sets whether the right-to-left direction is enabled for the MultiSelect Dropdown component.

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

true, if the right to left direction can be enabled. Otherwise, false. The default value is false.

EnableSelectionOrder

Gets or sets a value indicating whether the selection order is enabled in the MultiSelect Dropdown component.

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

true, if the selection order can be enabled. Otherwise, false. The default value is true.

EnableVirtualization

Gets or sets a value indicating whether virtualization is enabled for the MultiSelect Dropdown component.

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

true if virtualization is enabled; otherwise, false..
Remarks

The Virtual Scrolling feature is used to display a large amount of data that you require without buffering an entire load of huge database records in the DropDowns, that is, when scrolling, the datamanager request is sent to fetch some amount of data from the server dynamically.

FilterBarPlaceholder

Gets or sets the placeholder text displayed in the filter bar of the MultiSelect Dropdown component.

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

The placeholder text for the filter bar.

FloatLabelType

Gets or sets the type of floating label to be displayed in the MultiSelect Dropdown component.

Declaration
public FloatLabelType FloatLabelType { get; set; }
Property Value
Type Description
FloatLabelType

Possible values are: Never: Never floats the label in the MultiSelect when the placeholder is available. Always: The floating label always floats above the MultiSelect. Auto: The floating label floats above the MultiSelect after focusing it or when entering the value in it.

FooterTemplate

Gets or sets the template to be rendered as the footer of the dropdown popup in the MultiSelect component.

Declaration
public RenderFragment FooterTemplate { get; set; }
Property Value
Type Description
Microsoft.AspNetCore.Components.RenderFragment

The template content. The default value in null

HeaderTemplate

Gets or sets the template to be rendered as the header of the dropdown popup in the MultiSelect component.

Declaration
public RenderFragment HeaderTemplate { get; set; }
Property Value
Type Description
Microsoft.AspNetCore.Components.RenderFragment

The template content. The default value in null

HideSelectedItem

Gets or sets a value indicating whether the selected item should be hidden in the popup list of the MultiSelect Dropdown component.

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

true if the selected item should be hidden; otherwise, false.

HtmlAttributes

Gets or sets the HTML attributes to be applied to the MultiSelect Dropdown component.

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

The HTML attributes as a dictionary.
Remarks

If you configured both the property and equivalent input attribute, then the component considers the property value.

ID

Gets or sets the identifier of the MultiSelect Dropdown component.

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

Accepts the string value.

InputAttributes

You can add the additional input attributes such as disabled, value, and more to the root element.

If you configured both the property and equivalent input attribute, then the component considers the property value.

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

A dictionary of additional input attributes for the root element of the component.

ItemsCount

Gets or sets the number of items to be fetched in the popup based on the ItemsCount when EnableVirtualization is enabled.

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

An integer value representing the number of items to be fetched. The default value is 5.

MaximumSelectionLength

Gets or sets the maximum number of items that can be selected in the MultiSelect Dropdown component.

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

An integer value representing the maximum number of items that can be selected in the list. The default value is 1000.

Mode

Gets or sets the visual mode of the MultiSelect Dropdown component.

Declaration
public VisualMode Mode { get; set; }
Property Value
Type Description
VisualMode

The visual mode of the MultiSelect Dropdown. The default value is Default.

OpenOnClick

Gets or sets a value indicating whether the dropdown should open when the MultiSelect component is clicked.

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

true if the dropdown should open on click; otherwise, false. The default value is true.

Placeholder

Gets or sets the placeholder text to be displayed in the MultiSelect input when no items are selected.

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

Accepts the string value.

PopupDisplayMode

Gets or sets the display mode of the dropdown popup on mobile devices.

Declaration
public PopupDisplayMode PopupDisplayMode { get; set; }
Property Value
Type Description
PopupDisplayMode

The default value is FullScreen.
Remarks

The PopupDisplayMode enum has two possible values:

Examples

The following example demonstrates how to use the PopupDisplayMode property:

MultiSelect with PopupDisplayMode set to FullScreen
<SfMultiSelect TValue="List<string>" DataSource="@Data" PopupDisplayMode="PopupDisplayMode.FullScreen" Mode="CheckBox" AllowFiltering="true">
    <MultiSelectFieldSettings Text="Text" Value="Id"></MultiSelectFieldSettings>
</SfMultiSelect>

@code {
    public List<MultiSelectData> Data { get; set; } = new List<MultiSelectData>
    {
        new MultiSelectData { Id = "1", Text = "Option 1" },
        new MultiSelectData { Id = "2", Text = "Option 2" },
        new MultiSelectData { Id = "3", Text = "Option 3" }
    };

    public class MultiSelectData
    {
        public string Id { get; set; }
        public string Text { get; set; }
    }
}

PopupHeight

Gets or sets the height of the dropdown popup in the MultiSelect component.

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

Accepts the string value. The default value is 300px.

PopupWidth

Gets or sets the width of the dropdown popup in the MultiSelect component.

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

Accepts the string value. The default value is 100%.

Readonly

Gets or sets a value indicating whether the MultiSelect component is in read-only mode.

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

true if the MultiSelect component is read-only; otherwise, false. The default value is false.

SelectAllText

Gets or sets the text to be displayed for the "Select All" option in the MultiSelect component.

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

Accepts the string value.

ShowClearButton

Gets or sets a value indicating whether the MultiSelect Dropdown should display a clear button to clear the selected values.

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

true if the clear button should be shown; otherwise, false. The default value is true.

ShowDropDownIcon

Gets or sets a value indicating whether the dropdown icon should be shown in the MultiSelect component.

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

true if the dropdown icon should be shown; otherwise, false. The default value is true.

ShowSelectAll

Gets or sets a value indicating whether the Select All option should be shown in the MultiSelect component for the CheckBox mode.

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

true, if the select all option should be shown. Otherwise, false.

TabIndex

Gets or sets the tab index of the MultiSelect component.

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

The tab index of the MultiSelect component. The default value is 0.

Text

Gets or sets the selected list item which maps the data Text field in the component.

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

Accepts the string value.

UnSelectAllText

Gets or sets the text to be displayed for the Unselect All option in the MultiSelect component for the CheckBox mode.

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

Accepts the string value.

Value

Gets the value of the selected item in the MultiSelect Dropdown component. This will be used with two-way binding.

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

The current value of the multi select component.

ValueChanged

Gets or sets a callback that trigger when the value changes.

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

An event callback function.

ValueExpression

Specifies the expression for defining the value of the bound.

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

ValueTemplate

Gets or sets the customised design content and assigns it to the selected list item in the input element of the component.

Declaration
public RenderFragment<TItem> ValueTemplate { get; set; }
Property Value
Type Description
Microsoft.AspNetCore.Components.RenderFragment<TItem>

The template content. The default value in null

Width

Gets or sets the width of the MultiSelect component.

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

Accepts the string value. The default value is 100%.

Methods

BuildRenderTree(RenderTreeBuilder)

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

ClearAsync()

Clears all selected values in the MultiSelect component, restoring it to its default state.

Declaration
public Task ClearAsync()
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the asynchronous clear operation.
Remarks

This method will remove all currently selected items from the MultiSelect, returning it to no-selection. Use this to programmatically reset selections (for example, in a form reset workflow).

Examples
await multiSelectRef.ClearAsync(); // Clears all selections

DisableItem(Object)

Disables a specific item in the MultiSelect list, based on value or item index.

Declaration
public Task DisableItem(object item)
Parameters
Type Name Description
System.Object item

The unique item value, corresponding TValue object, or integer index of the item to disable.
Returns
Type
System.Threading.Tasks.Task
Remarks

Use this method to programmatically disable a single item in the popup. If a string or TValue is provided, it matches by value; if an System.Int32, it matches by index in the item list.

Examples
await multiSelectRef.DisableItem("US"); // Disable the item with value "US"
await multiSelectRef.DisableItem(2);    // Disable the item at index 2

FilterAsync(IEnumerable<TItem>, Query, FieldSettingsModel)

Filters the supplied dataSource using the specified query and field mapping.

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

The enumerable data source to apply the custom filter logic on.
Query query

A Query instance describing custom filtering, sorting, or paging rules. May be null for unfiltered lists.
FieldSettingsModel fields

Optional field mapping configuration for data binding and filter operation.
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the asynchronous filtering operation.
Remarks

This method can be used to replace the displayed items dynamically at runtime by supplying a new dataSource and filter rules. Filtering can be combined with virtualization.

Examples
await multiSelectRef.FilterAsync(myData, new Query().Where("Country", "==", "USA")); // Shows only filtered items

FilteringActionAsync(IEnumerable<TItem>, Query, FieldSettingsModel)

Performs filtering on the data source based on current input/query and updates the visible list in the dropdown popup.

Declaration
protected Task FilteringActionAsync(IEnumerable<TItem> dataSource, Query query, FieldSettingsModel fields)
Parameters
Type Name Description
System.Collections.Generic.IEnumerable<TItem> dataSource

The underlying list of items to filter.
Query query

The query/filter expression; may be null for no query.
FieldSettingsModel fields

Field mapping information for the MultiSelect component.
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the data filtering and UI update operation.

FocusAsync()

Sets focus to the SfMultiSelect<TValue, TItem> component, enabling immediate user interaction.

Declaration
public Task FocusAsync()
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the asynchronous operation.
Remarks

Use this method to programmatically move keyboard focus to the MultiSelect input. This is useful when needing to set focus due to user action, form workflow, or UI navigation outside the standard tab order.

Examples
await multiSelectRef.FocusAsync(); // Sets input focus programmatically

FocusOutAsync()

Removes focus from the SfMultiSelect<TValue, TItem> component if it is currently focused.

Declaration
public Task FocusOutAsync()
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the asynchronous operation.
Remarks

Call this method to programmatically remove keyboard focus from the MultiSelect control, such as after form completion or on specific workflow steps.

Examples
await multiSelectRef.FocusOutAsync(); // Removes input focus programmatically

GetDataByValueAsync(TValue)

Returns the collection of TItem data objects matching the provided selection values.

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

The one or more selection values (of type TValue) to search for, and retrieve the mapped data objects.
Returns
Type Description
System.Threading.Tasks.Task<System.Collections.Generic.List<TItem>>

A Task<List<TItem>> containing all available data objects for the given input values.
Remarks

For each value in dataValue, this method will search the MultiSelect list and return the corresponding data object(s) if present. Supports array, collection, and primitive input cases.

Examples
var selectedItems = await multiSelectRef.GetDataByValueAsync(new string[] { "US", "UK" }); // Get all selected item objects

GetForQuery(List<Object>, Boolean)

Creates a query to filter (or exclude) a set of items with certain values, used with virtualization and select-all/checkbox logic.

Declaration
protected Query GetForQuery(List<object> values, bool isCheckBox = false)
Parameters
Type Name Description
System.Collections.Generic.List<System.Object> values

A list of item values to be included in (or excluded from) the results set.
System.Boolean isCheckBox

Indicates if the operation is for checkbox (select-all) logic.
Returns
Type Description
Query

A Query containing complex filter logic for the specified values and mode.

GetItemsAsync()

Retrieves all TItem data items currently bound and available in the MultiSelect control's list.

Declaration
public Task<IEnumerable<TItem>> GetItemsAsync()
Returns
Type Description
System.Threading.Tasks.Task<System.Collections.Generic.IEnumerable<TItem>>

A Task<IEnumerable<TItem>> representing the asynchronous retrieval of all items.
Remarks

Call this method to enumerate all items currently in the MultiSelect’s internal data list. This can be useful for inspection, debugging, or for building custom logic based on all available items.

Examples
IEnumerable<Country> items = await multiSelectRef.GetItemsAsync(); // Fetches all data-bound items

HidePopupAsync()

Closes the MultiSelect dropdown popup if it is currently open.

Declaration
public Task HidePopupAsync()
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the asynchronous close operation.
Remarks

Call this method to programmatically close the MultiSelect's dropdown popup. Useful for custom UI workflows or when a user/caller needs to close the popup via external actions or programmatic logic.

Examples
await multiSelectRef.HidePopupAsync(); // Closes dropdown popup

RefreshDataAsync()

Reloads and refreshes the list of items displayed in the MultiSelect dropdown popup with the current data source.

Declaration
public Task RefreshDataAsync()
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the asynchronous refresh operation.
Remarks

Use this method when the DataSource is changed or if you modify the items collection externally and need the dropdown to reflect these updates. The method will re-render the list and reapply the selected values.

Examples
await multiSelectRef.RefreshDataAsync(); // Refreshes MultiSelect display with latest data

SelectAllAsync(Boolean)

Selects or deselects all items in the MultiSelect dropdown, depending on the specified state value.

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

If true, all items in the list are selected; if false, all items are deselected.
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the asynchronous select/deselect operation.
Remarks

Call this method to programmatically select or deselect all available items in the MultiSelect dropdown. This is especially useful in scenarios with checkbox mode or when implementing custom select/clear all UI.

Examples
// Select all items
await multiSelectRef.SelectAllAsync(true);
// Deselect all items
await multiSelectRef.SelectAllAsync(false);

SetCurrentViewDataAsync(Int32, Int32)

Declaration
protected override Task SetCurrentViewDataAsync(int virtualItemStartIndex, int virtualItemEndIndex)
Parameters
Type Name Description
System.Int32 virtualItemStartIndex
System.Int32 virtualItemEndIndex
Returns
Type
System.Threading.Tasks.Task
Overrides
Syncfusion.Blazor.DropDowns.SfDropDownBase<TItem>.SetCurrentViewDataAsync(System.Int32, System.Int32)

ShowPopupAsync()

Opens and displays the MultiSelect dropdown popup, allowing selection from the available items programmatically.

Declaration
public Task ShowPopupAsync()
Returns
Type Description
System.Threading.Tasks.Task

A System.Threading.Tasks.Task representing the asynchronous open operation.
Remarks

This method programmatically triggers the dropdown popup, bypassing the need for user clicking the input. Use for advanced UI scenarios like opening the dropdown based on keyboard command, API call, or workflow trigger.

Examples
await multiSelectRef.ShowPopupAsync(); // Opens dropdown popup from code

StartResizingHandler(Object)

Starts the popup resizing operation for the MultiSelect dropdown (advanced scenarios; called via JS interop or custom UI logic).

Declaration
public Task StartResizingHandler(object eventArguments = null)
Parameters
Type Name Description
System.Object eventArguments

Optional event argument payload for the resize start event.
Returns
Type Description
System.Threading.Tasks.Task

Task representing the resize start operation.

StopResizingHandler(Object, Double)

Completes the popup resizing operation for the MultiSelect dropdown (advanced scenarios; called via JS interop or resize stop actions).

Declaration
public Task StopResizingHandler(object eventArguments = null, double resizeHeight = 0)
Parameters
Type Name Description
System.Object eventArguments

Optional event argument payload for the resize stop event.
System.Double resizeHeight

The new height value (in pixels) for the dropdown popup after resizing.
Returns
Type Description
System.Threading.Tasks.Task

Task representing the resize stop operation.

UpdateValueAsync()

Task which updates the value.

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

Task.

Implements

Syncfusion.Blazor.DropDowns.IVirtualList<T>