Blazorise Autocomplete component

The Autocomplete component offers simple and flexible type-ahead functionality.

The Autocomplete component provides suggestions while you type into the field. The component is in essence a text box which, at runtime, filters data in a drop-down by a Filter operator when a user captures a value. You may also enable FreeTyping and Autocomplete can be used to just provide suggestions based on user input.

Quick Installation

Step 1: Download from NuGet

Install extension from NuGet: 
Install-Package Blazorise.Components

Step 2. Define Usings

In your main _Imports.razor add: 
@using Blazorise.Components

Examples

Searching single value

Selected search value:
Selected text value: 
<Autocomplete TItem="Country"
              TValue="string"
              Data="@Countries"
              TextField="@(( item ) => item.Name)"
              ValueField="@(( item ) => item.Iso)"
              @bind-SelectedValue="@selectedSearchValue"
              @bind-SelectedText="selectedAutoCompleteText"
              Placeholder="Search..."
              Filter="AutocompleteFilter.StartsWith"
              FreeTyping
              CustomFilter="@(( item, searchValue ) => item.Name.IndexOf( searchValue, 0, StringComparison.CurrentCultureIgnoreCase ) >= 0 )">
    <NotFoundContent> Sorry... @context was not found! :( </NotFoundContent>
</Autocomplete>

<Field Horizontal>
    <FieldBody ColumnSize="ColumnSize.Is12">
        Selected search value: @selectedSearchValue
    </FieldBody>
    <FieldBody ColumnSize="ColumnSize.Is12">
        Selected text value: @selectedAutoCompleteText
    </FieldBody>
</Field>

@code {
    [Inject]
    public CountryData CountryData { get; set; }
    public IEnumerable<Country> Countries;

    protected override async Task OnInitializedAsync()
    {
        Countries = await CountryData.GetDataAsync();
        await base.OnInitializedAsync();
    }

    public string selectedSearchValue { get; set; }
    public string selectedAutoCompleteText { get; set; }
}

Searching multiple values

United Arab EmiratesAlbania
Selected Values: AE,AL
Selected Texts: United Arab Emirates,Albania
<Autocomplete TItem="Country"
              TValue="string"
              Data="@Countries"
              TextField="@(( item ) => item.Name)"
              ValueField="@(( item ) => item.Iso)"
              Placeholder="Search..."
              SelectionMode="AutocompleteSelectionMode.Multiple"
              FreeTyping
              @bind-SelectedValues="multipleSelectionData"
              @bind-SelectedTexts="multipleSelectionTexts">
</Autocomplete>

<Field Horizontal>
    <FieldBody ColumnSize="ColumnSize.Is12">
        Selected Values: @string.Join(',', multipleSelectionData)
    </FieldBody>
    <FieldBody ColumnSize="ColumnSize.Is12">
        Selected Texts: @(multipleSelectionTexts == null ? null : string.Join(',', multipleSelectionTexts))
    </FieldBody>
</Field>

@code {
    [Inject]
    public CountryData CountryData { get; set; }
    public IEnumerable<Country> Countries;

    protected override async Task OnInitializedAsync()
    {
        Countries = await CountryData.GetDataAsync();
        multipleSelectionData = new List<string>() { Countries.ElementAt( 1 ).Iso, Countries.ElementAt( 3 ).Iso };
        await base.OnInitializedAsync();
    }

    List<string> multipleSelectionData;
    List<string> multipleSelectionTexts;
}

Searching with data on demand (ReadData)

Frequently, you'll want to read data on demand rather than loading everything into memory at startup. You can do it with the ReadData API. It will provide you with enough information for you to call an external data-source, which will return new data, which you can then reassign to the Data parameter.
Selected search value:
Selected text value: 
<Autocomplete TItem="Country"
              TValue="string"
              Data="@ReadDataCountries"
              ReadData="@OnHandleReadData"
              TextField="@(( item ) => item.Name)"
              ValueField="@(( item ) => item.Iso)"
              @bind-SelectedValue="@selectedSearchValue"
              @bind-SelectedText="selectedAutoCompleteText"
              Placeholder="Search..."
              FreeTyping>
    <NotFoundContent> Sorry... @context was not found! :( </NotFoundContent>
</Autocomplete>

<Field Horizontal>
    <FieldBody ColumnSize="ColumnSize.Is12">
        Selected search value: @selectedSearchValue
    </FieldBody>
    <FieldBody ColumnSize="ColumnSize.Is12">
        Selected text value: @selectedAutoCompleteText
    </FieldBody>
</Field>

@code {
    [Inject]
    public CountryData CountryData { get; set; }
    public IEnumerable<Country> Countries;
    public IEnumerable<Country> ReadDataCountries;

    private Random random = new();

    public string selectedSearchValue { get; set; }
    public string selectedAutoCompleteText { get; set; }

    protected override async Task OnInitializedAsync()
    {
        Countries = await CountryData.GetDataAsync();
        await base.OnInitializedAsync();
    }

    private async Task OnHandleReadData( AutocompleteReadDataEventArgs autocompleteReadDataEventArgs )
    {
        if ( !autocompleteReadDataEventArgs.CancellationToken.IsCancellationRequested )
        {
            await Task.Delay( random.Next( 100 ) );
            if ( !autocompleteReadDataEventArgs.CancellationToken.IsCancellationRequested )
            {
                ReadDataCountries = Countries.Where( x => x.Name.StartsWith( autocompleteReadDataEventArgs.SearchValue, StringComparison.InvariantCultureIgnoreCase ) );
            }
        }
    }
}

Extending with custom item content

Customize the way you display the Autocomplete items by providing ItemContent.
Selected search value:
Selected text value: 
<Autocomplete TItem="Country"
              TValue="string"
              Data="@Countries"
              TextField="@(( item ) => item.Name)"
              ValueField="@(( item ) => item.Iso)"
              @bind-SelectedValue="@selectedSearchValue"
              @bind-SelectedText="selectedAutoCompleteText"
              Placeholder="Search..."
              Filter="AutocompleteFilter.StartsWith"
              FreeTyping
              CustomFilter="@(( item, searchValue ) => item.Name.IndexOf( searchValue, 0, StringComparison.CurrentCultureIgnoreCase ) >= 0 )">
    <NotFoundContent> Sorry... @context was not found! :( </NotFoundContent>
    <ItemContent>
        <Div Flex="Flex.InlineFlex.JustifyContent.Between" Width="Width.Is100">
            <Heading Margin="Margin.Is2.FromBottom">@context.Value</Heading>
            <Small>@context.Item.Capital</Small>
        </Div>
        <Paragraph Margin="Margin.Is2.FromBottom">@context.Text</Paragraph>
    </ItemContent>
</Autocomplete>

<Field Horizontal>
    <FieldBody ColumnSize="ColumnSize.Is12">
        Selected search value: @selectedSearchValue
    </FieldBody>
    <FieldBody ColumnSize="ColumnSize.Is12">
        Selected text value: @selectedAutoCompleteText
    </FieldBody>
</Field>

@code {
    [Inject]
    public CountryData CountryData { get; set; }
    public IEnumerable<Country> Countries;

    protected override async Task OnInitializedAsync()
    {
        Countries = await CountryData.GetDataAsync();
        await base.OnInitializedAsync();
    }
    string selectedSearchValue { get; set; }
    string selectedAutoCompleteText { get; set; }
}

Suggesting already selected items && Checkbox support

You can use SuggestSelectedItems to suggest already selected items, and optionally use SuggestMultipleCheckbox to additionally add checkbox selection. Note: Make sure to set CloseOnSelection to false if you want to keep the dropdown open whenever an item is selected.
United Arab EmiratesAlbania
Selected Values: AE,AL
Selected Texts: United Arab Emirates,Albania
<Autocomplete TItem="Country"
              TValue="string"
              Data="@Countries"
              TextField="@(( item ) => item.Name)"
              ValueField="@(( item ) => item.Iso)"
              Placeholder="Search..."
              SelectionMode="AutocompleteSelectionMode.Checkbox"
              CloseOnSelection="false"
              @bind-SelectedValues="multipleSelectionData"
              @bind-SelectedTexts="multipleSelectionTexts">
</Autocomplete>

<Field Horizontal>
    <FieldBody ColumnSize="ColumnSize.Is12">
        Selected Values: @string.Join(',', multipleSelectionData)
    </FieldBody>
    <FieldBody ColumnSize="ColumnSize.Is12">
        Selected Texts: @(multipleSelectionTexts == null ? null : string.Join(',', multipleSelectionTexts))
    </FieldBody>
</Field>

@code {
    [Inject]
    public CountryData CountryData { get; set; }
    public IEnumerable<Country> Countries;

    protected override async Task OnInitializedAsync()
    {
        Countries = await CountryData.GetDataAsync();
        multipleSelectionData = new List<string>() { Countries.ElementAt( 1 ).Iso, Countries.ElementAt( 3 ).Iso };
        await base.OnInitializedAsync();
    }

    List<string> multipleSelectionData;
    List<string> multipleSelectionTexts;
}

Highlight search text

Autocomplete HighlightSearch is a feature that allows you to highlight the search text that you have entered in a dropdown list of items. When you start typing in the search field, the dropdown list of items will automatically be filtered to show only the items that match the search text. The search text will also be highlighted in the dropdown list of items, so that you can easily see which items match your search. This can be a useful feature when you are trying to find a specific item in a long list of items, as it allows you to quickly locate the item you are looking for. 
<Autocomplete TItem="Country"
              TValue="string"
              Data="@Countries"
              TextField="@(( item ) => item.Name)"
              ValueField="@(( item ) => item.Iso)"
              Placeholder="Search..."
              HighlightSearch>
    <NotFoundContent> Sorry... @context was not found! :( </NotFoundContent>
</Autocomplete>

@code {
    [Inject]
    public CountryData CountryData { get; set; }
    public IEnumerable<Country> Countries;

    protected override async Task OnInitializedAsync()
    {
        Countries = await CountryData.GetDataAsync();
        await base.OnInitializedAsync();
    }
}

Virtualize

Blazorise Autocomplete's Virtualize feature allows for loading data on demand while scrolling, which improves the performance of the component when working with large datasets. With Virtualize, the Autocomplete component only loads the items that are currently visible in the list, and as the user scrolls, more items are loaded in the background. This allows for a much faster and smoother user experience, especially when working with large lists of items.

This feature can be easily enabled by setting the Virtualize property to "true" on the Autocomplete component. 

<Autocomplete TItem="Country"
              TValue="string"
              Data="@Countries"
              TextField="@(( item ) => item.Name)"
              ValueField="@((item) => item.Iso)"
              @bind-SelectedValue="selectedSearchValue"
              Placeholder="Search..."
              Virtualize>
    <NotFoundContent> Sorry... @context was not found! :( </NotFoundContent>
</Autocomplete>

@code {
    [Inject]
    public CountryData CountryData { get; set; }
    public IEnumerable<Country> Countries;

    protected override async Task OnInitializedAsync()
    {
        Countries = await CountryData.GetDataAsync();
        await base.OnInitializedAsync();
    }

    public string selectedSearchValue { get; set; }
}

API

Attributes

Name Description Type Default
TItem Model data type. generic
Data Data used for the search. IEnumerable<TItem>
TextField Selector for the display name field. Func
ValueField Selector for the value field. Func
SelectedValue Currently selected value. object
SelectedValueChanged Raises an event after the selected value has changed. EventCallback<string>
SelectedText Currently selected text. string
SelectedTextChanged Raises an event after the selected text has changed. EventCallback<string>
CurrentSearch Gets or sets the currently selected item text. CurrentSearch is deprecated and will be removed in a future version, please use Search instead. string
CurrentSearchChanged Occurs on every search text change. CurrentSearchChanged is deprecated and will be removed in a future version, please use SearchChanged instead. EventCallback<string>
Search Gets or sets the currently selected item text. string
SearchChanged Occurs on every search text change. EventCallback<string>
Placeholder Placeholder for the empty search field. string
MinLength Minimum number of character needed to start search. Set this to 0 to make the Autocomplete function like a dropdown. int 1
MaxMenuHeight Sets the maximum height of the dropdown menu. string 200px
Filter Filter method used to search the data. enum StartsWith
Disabled Disable the input field. bool false
Immediate If true the text in will be changed after each key press (overrides global settings). bool? null
Debounce If true the entered text will be slightly delayed before submitting it to the internal value. bool? null
DebounceInterval Interval in milliseconds that entered text will be delayed from submitting to the internal value. int? null
Validator Validation handler used to validate selected value. Action<ValidatorEventArgs> null
AsyncValidator Asynchronously validates the selected value. Func<ValidatorEventArgs, CancellationToken, Task> null
NotFoundContent Render fragment when no value has been found on the data source. RenderFragment<string>
NotFound Raises an event when no value has been found on the data source. EventCallback<string>
FreeTyping Allows the value to not be on the data source. bool false
CustomFilter Handler for custom filtering on Autocomplete’s data source. Func<TItem, string, bool>
Multiple Allows for multiple selection. Multiple parameter will be removed in a future version, please replace with SelectionMode.Multiple Parameter instead. bool false
MultipleBadgeColor Sets the Badge color for the multiple selection values. Used when multiple selection is set. Color Color.Primary
MultipleDisabledBadgeColor Sets the disabled Badge color for the multiple selection values. Used when multiple selection is set. Color Color.Light
SelectedValues Currently selected items values. List<TValue>
SelectedValuesChanged Occurs after the selected values have changed. EventCallback<List<TValue>>
SelectedTexts Currently selected items texts. List<string>
SelectedTextsChanged Occurs after the selected texts have changed. EventCallback<List<string>>
ItemContent Specifies the item content to be rendered inside each dropdown item. RenderFragment<ItemContext<TItem,TValue>>
CloseOnSelection Specifies whether Autocomplete's dropdown closes on selection. This is only evaluated when multiple selection is set. Defauls to true. bool true
ReadData Event handler used to load data manually by based on the current search value. EventCallback<AutoCompleteReadDataEventArgs>
SuggestSelectedItems Suggests already selected option(s) when presenting the options. bool false
ConfirmKey Gets or sets an array of the keyboard pressed values for the ConfirmKey. If this is null or empty, there will be no confirmation key. string[] new[] { "Enter", "NumpadEnter" }
AutoPreSelect Gets or sets whether Autocomplete auto preselects the first item when the drop down opens. bool true
AutoSelectFirstItem Gets or sets whether Autocomplete auto preselects the first item from the data list on initialization. This overrides initial SelectedValue. bool false
SelectionMode Gets or sets the Autocomplete Selection Mode. AutocompleteSelectionMode AutocompleteSelectionMode.Default
HighlightSearch If true, the searched text will be highlighted in the dropdown list items based on Search value. bool false
SearchBackground Defines the background color of the search field. Background null
SearchTextColor Defines the text color of the search field. TextColor null
Closed Event handler used to detect when the autocomplete is closed. EventCallback<AutocompleteClosedEventArgs>
Opened Event handler used to detect when the autocomplete is opened. EventCallback
FreeTypingNotFoundTemplate Specifies the not found content to be rendered when no data is found and FreeTyping is enabled. RenderFragment<string>

Methods

Name Description Type Default
ScrollItemIntoView Scrolls an item into view.
Reload Triggers the reload of the Autocomplete data. Makes sure not to reload if the Autocomplete is in a loading state.
AddMultipleTextAndValue Adds a Multiple Selection.
RemoveMultipleTextAndValue Removes a Multiple Selection.
Clear Clears the selected value and the search field.
ResetSelected Clears the current selection.
OpenDropdown Opens the Autocomplete Dropdown.
Close Closes the Autocomplete Dropdown.
IsSelectedvalue Gets whether the TValue is selected.
IsSelectedItem Gets whether the TItem is selected.
GetItemByValue Gets a TItem from Data by using the provided ValueField.
GetItemByText Gets a TItem from Data by using the provided TextField.
IsSafeToClose IsSafeToClose is deprecated. This API now always returns true.
MaxEntryLength Specifies the maximum number of characters allowed in the input element.
Virtualize Gets or sets whether the Autocomplete will use the Virtualize functionality. bool false
TagTemplate Specifies the badge content to be rendered for each tag (multiple selected item). RenderFragment<AutocompleteTagContext<TItem, TValue>>
SearchTextChanged Occurs after the search box text has changed. EventCallback<string>
SearchKeyDown Occurs when a key is pressed down while the search box has focus. EventCallback<KeyboardEventArgs>
SearchFocus Occurs when the search box gains or loses focus. EventCallback<FocusEventArgs>
SearchBlur The blur event fires when the search box has lost focus. EventCallback<FocusEventArgs>
PositionStrategy Defines the positioning strategy of the dropdown menu as a 'floating' element. DropdownPositionStrategy Fixed
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