ComboBox Filter
The ComboBox component allows the user to filter the available items by their text, so they can find the one they need faster.
To enable filtering, set the Filterable parameter to true. The filtering is case insensitive. You can also implement custom (server) filtering and set a data source dynamically through the OnRead event.
Filtering looks in the TextField, and the filter is reset when the dropdown closes.
Filter Operator
The default filter operator is starts with. You can choose a different operator through the FilterOperator parameter that takes a member of the Telerik.Blazor.StringFilterOperator enum.
Performance
By default, the filtering is debounced with 150ms. Configure that with the DebounceDelay parameter of the component.
Filtering Example
Filtering in the ComboBox
<ul>
<li>
<label>
Filter operator:
<TelerikDropDownList @bind-Value="@FilterOperator"
Data="@FilterOperators"
Width="160px" />
</label>
</li>
<li>
<label>
Debounce delay:
<TelerikNumericTextBox @bind-Value="@DebounceDelay" Min="0" Width="120px" />
</label>
</li>
</ul>
<br />
<TelerikComboBox Data="@ProductList"
@bind-Value="@SelectedProduct"
TextField="@nameof(Product.Name)"
ValueField="@nameof(Product.Id)"
Filterable="true"
FilterOperator="@FilterOperator"
DebounceDelay="@DebounceDelay"
Placeholder="Type digits to see filtering in action"
ClearButton="true"
Width="300px">
</TelerikComboBox>
@code{
private List<Product> ProductList { get; set; }
private int? SelectedProduct { get; set; }
private List<StringFilterOperator> FilterOperators =>
Enum.GetValues(typeof(StringFilterOperator)).Cast<StringFilterOperator>().ToList();
private StringFilterOperator FilterOperator { get; set; } = StringFilterOperator.StartsWith;
private int DebounceDelay { get; set; } = 150;
protected override void OnInitialized()
{
ProductList = new List<Product>();
for (int i = 1; i <= 30; i++)
{
ProductList.Add(new Product()
{
Id = i,
Name = $"{i} Product {i * 111}"
});
}
base.OnInitialized();
}
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
}
}