SearchCombobox/testWPFDevelopers/MainWindow.xaml.cs

using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace testWPFDevelopers
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        List<string> list = new List<string> { "aa", "bb", "abc", "csd", "sdlfks", "osdi", "awd" , "aa", "bb", "abc", "csd", "sdlfks", "osdi", "awd", "aa", "bb", "abc", "csd", "sdlfks", "osdi", "awd" };
        public MainWindow()
        {
            InitializeComponent();
            this.DataContext=new MainViewModel();
            comboBox1.ItemsSource = list;
        }
        private void comboBox1_KeyUp(object sender, KeyEventArgs e)
        {

            List<string> mylist = new List<string>();
            mylist = list.FindAll(delegate (string s) { return s.Contains(comboBox1.Text.Trim()); });
            comboBox1.ItemsSource = mylist;
            comboBox1.IsDropDownOpen = true;
        }
    }

}