You can use the AutoExpandSelection property to specify whether DropDown control automatically fills the text box portion of a combo box with a value from the combo box list that matches the characters you enter as you type in the combo box.

AutoExpandSelection property is available in the following Input DropDown controls;

• InputColor
• InputDate
• AutoComplete, ComboBox
• InputTime

The following code example demonstrates how to use AutoExpandSelection in the Input control.

public ActionResult Index()
  {
ViewBag.Cities = Models.Cities.GetCities();
return View();
   }

Index.cshtml

@{
    List<string> cities = ViewBag.Cities;
<div>
    <c1-combo-box selected-index=0 auto-expand-selection="true">
        <c1-items-source source-collection=@cities></c1-items-source>
    </c1-combo-box>
</div>