だって検索したいじゃん

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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 ImFeelingLucky
{
    /// <summary>
    /// MainWindow.xaml の相互作用ロジック
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Google_Click(object sender, RoutedEventArgs e)
        {
            DoSearch(1);
        }

        private void ImFeelingLucky_Click(object sender, RoutedEventArgs e)
        {
            DoSearch(2);
        }

        private void Yahoo_Click(object sender, RoutedEventArgs e)
        {
            DoSearch(3);
        }

        private void Bing_Click(object sender, RoutedEventArgs e)
        {
            DoSearch(4);
        }

        void DoSearch(int i)
        {
            string SearchText = Uri.EscapeUriString(SearchBox.Text);
            
            switch (i)
            {
                case 1:
                    Process.Start("https://www.google.co.jp/search?q=" + SearchText);
                    break;
                case 2:
                    Process.Start("https://www.google.co.jp/search?btnI=I%27m+Feeling+Lucky&q=" + SearchText);
                    break;
                case 3:
                    Process.Start("http://search.yahoo.co.jp/search?p=" + SearchText);
                    break;
                case 4:
                    Process.Start("http://www.bing.com/search?q=" + SearchText);
                    break;
            }

            SearchBox.Text = null;
        }

        private void SearchBox_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Return)
            {
                DoSearch(2);
            }
        }
    }
}