jqwidgets-framework/demos/Angular/src/dropdownlist/autoopen/app.component.html

jQWidgets is an advanced Angular, Vue, Blazor, React, Web Components, jquery, ASP .NET MVC, Custom Elements and HTML5 UI framework.

<jqxDropDownList
    [width]="200" [height]="30" [source]="source" [selectedIndex]="1" [autoOpen]="true">
</jqxDropDownList>