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Class ComboBoxEvents<TValue, TItem> - Blazor API Reference | Syncfusion

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    Class ComboBoxEvents<TValue, TItem>

    Represents the event handlers for a ComboBox component in the Blazor framework.

    Inheritance
    System.Object
    ComboBoxEvents<TValue, TItem>
    Namespace: Syncfusion.Blazor.DropDowns
    Assembly: Syncfusion.Blazor.dll
    Syntax
    public class ComboBoxEvents<TValue, TItem> : OwningComponentBase
    Type Parameters
    Name Description
    TValue

    The type of value associated with the ComboBox.

    TItem

    The type of item associated with the ComboBox.

    Constructors

    ComboBoxEvents()

    Declaration
    public ComboBoxEvents()

    Properties

    Blur

    Gets or sets the event callback that will be invoked when the ComboBox component loses focus.

    Declaration
    public EventCallback<object> Blur { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<System.Object>

    Closed

    Gets or sets the event callback that will be invoked after the dropdown popup has been closed.

    Declaration
    public EventCallback<ClosedEventArgs> Closed { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<ClosedEventArgs>

    Created

    Gets or sets the event callback that will be invoked when the component is created.

    Declaration
    public EventCallback<object> Created { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<System.Object>

    CustomValueSpecifier

    Gets or sets the event callback that will be invoked when custom values (not present in the data source) are selected in the ComboBox component.

    Declaration
    public EventCallback<CustomValueSpecifierEventArgs<TItem>> CustomValueSpecifier { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<CustomValueSpecifierEventArgs<TItem>>
    Examples
    <SfComboBox TValue="int" TItem="Countries" DataSource="@CountryList">
       <ComboBoxEvents TValue="int" TItem="Countries" CustomValueSpecifier="@customValue"></ComboBoxEvents>
       <ComboBoxFieldSettings Text="Name" Value="Code"></ComboBoxFieldSettings>
    </SfComboBox>
    @code{
        public class Countries {
            public string Name { get; set; }
            public int Code { get; set; }
        }
        private List<Countries> CountryList = new List<Countries>() {
            new Countries(){ Code= 101, Name= "Australia" },
            new Countries(){ Code= 102, Name= "Canada" }
         }
        private void customValue(CustomValueSpecifierEventArgs<Countries> args) {
            args.Item = new Countries() { Code = 103, Name = args.Text };
        }
      }

    DataBound

    Gets or sets the event callback that will be invoked when the data source is populated in the popup list.

    Declaration
    public EventCallback<DataBoundEventArgs> DataBound { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<DataBoundEventArgs>

    Destroyed

    Gets or sets the event callback that will be invoked when the component is destroyed.

    Declaration
    public EventCallback<object> Destroyed { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<System.Object>

    Filtering

    Gets or sets the event callback that will be invoked on typing a character in the ComboBox.

    Declaration
    public EventCallback<FilteringEventArgs> Filtering { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<FilteringEventArgs>
    Remarks

    Prevent the default filter action and make your query enable the PreventDefaultAction event argument, and pass the modified data source and query in the FilterAsync(IEnumerable<TItem>, Query, FieldSettingsModel) method.

    Examples
    <SfComboBox @ref="ComboBoxObj" TItem="string" TValue="string" AllowFiltering="true" DataSource="@MyList">
        <ComboBoxEvents TValue="string" TItem="string" Filtering="@OnFilteringHandler" />
    </SfComboBox>
    @code{
        SfComboBox<string, string> ComboBoxObj { get; set; }
        protected List<string> MyList = new List<string>() { "Small", "Medium", "Large" };
        public async Task OnFilteringHandler(FilteringEventArgs args) {
            args.PreventDefaultAction = true;
            var query = new Query().Where(new WhereFilter() { Field = "Text", Operator = "contains", value = args.Text, IgnoreCase = true });
            await ComboBoxObj.FilterAsync(MyList, query);
        }
      }

    Focus

    Gets or sets the event callback that will be invoked when the component is the focus.

    Declaration
    public EventCallback<object> Focus { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<System.Object>

    OnActionBegin

    Gets or sets the event callback that will be invoked before fetching data from the data source.

    Declaration
    public EventCallback<ActionBeginEventArgs> OnActionBegin { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<ActionBeginEventArgs>

    OnActionComplete

    Gets or sets the event callback that will be invoked after data is fetched suction from the data source.

    Declaration
    public EventCallback<ActionCompleteEventArgs<TItem>> OnActionComplete { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<ActionCompleteEventArgs<TItem>>

    OnActionFailure

    Gets or sets the event callback that will be invoked when the data fetch request fails.

    Declaration
    public EventCallback<Exception> OnActionFailure { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<System.Exception>

    OnClose

    Gets or sets the event callback that will be invoked before the dropdown popup is closed.

    Declaration
    public EventCallback<PopupEventArgs> OnClose { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<PopupEventArgs>
    Remarks

    Prevent the dropdown popup close action using Cancel and the popup remains opened always.

    Examples
    <SfComboBox TItem="string" TValue="string" DataSource="@MyList">
        <ComboBoxEvents TValue="string" TItem="string" OnClose="@OnCloseHandler"/>
    </SfComboBox>
    @code{
        protected List<string> MyList = new List<string>() { "Small", "Medium", "Large" };
        public void OnCloseHandler(PopupEventArgs args) {
            args.Cancel = true;
        }
      }

    OnOpen

    Gets or sets the event callback that will be invoked when the dropdown popup before it opens.

    Declaration
    public EventCallback<BeforeOpenEventArgs> OnOpen { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<BeforeOpenEventArgs>
    Remarks

    Prevent the dropdown popup open action using Cancel.

    Examples
    <SfComboBox TItem="string" TValue="string" DataSource="@MyList">
        <ComboBoxEvents TValue="string" TItem="string" OnOpen="@OnOpenHandler"/>
    </SfComboBox>
    @code{
        protected List<string> MyList = new List<string>() { "Small", "Medium", "Large" };
        public void OnOpenHandler(BeforeOpenEventArgs args) {
            args.Cancel = true;
        }
      }

    OnValueSelect

    Gets or sets the event callback that will be invoked when an item is selected from the dropdown popup by the user either with a mouse tap or with a keyboard navigation.

    Declaration
    public EventCallback<SelectEventArgs<TItem>> OnValueSelect { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<SelectEventArgs<TItem>>
    Remarks

    Prevent the item selection action using Cancel.

    Examples
    <SfComboBox TItem="string" TValue="string" DataSource="@MyList">
        <ComboBoxEvents TValue="string" TItem="string" OnValueSelect="@OnSelectHandler" />
    </SfComboBox>
    @code{
        protected List<string> MyList = new List<string>() { "Small", "Medium", "Large" };
        public void OnSelectHandler(SelectEventArgs<string> args) {
            if(args.ItemData== "Medium")
                args.Cancel = true;
        }
      }

    Opened

    Gets or sets the event callback that will be invoked when the dropdown popup opens.

    Declaration
    public EventCallback<PopupEventArgs> Opened { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<PopupEventArgs>

    ValueChange

    Gets or sets the event callback that will be invoked when the Value property changed.

    Declaration
    public EventCallback<ChangeEventArgs<TValue, TItem>> ValueChange { get; set; }
    Property Value
    Type
    Microsoft.AspNetCore.Components.EventCallback<ChangeEventArgs<TValue, TItem>>
    Remarks

    This event triggers when an item in a popup is selected or when the user changes the model value.

    Examples
    <SfComboBox TItem="string" TValue="string" DataSource="@MyList">
        <ComboBoxEvents TValue="string" TItem="string" ValueChange="@OnChange"/>
    </SfComboBox>
    @code{
        protected List<string> MyList = new List<string>() { "Small", "Medium", "Large" };
        public void OnChange(Syncfusion.Blazor.DropDowns.ChangeEventArgs<string, string> args) {
            var NewValue = args.Value;
        }
      }

    Methods

    ComponentDispose(Boolean)

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