“System.Windows.Controls.TextBox”不包含“DataBindings”的定义是怎么回事？
using System;
using System.Collections.Generic;
using System.Linq;
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;
using System.Data.SqlClient;
using System.Data;
using System.Windows.Forms;


namespace SimpleBinding
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            string connstring = @"
                server=.\sqlexpress;
                integrated security=true;
                database=northwind";
            string sql = @"
                select
                *
                from
                employees";
            SqlConnection conn = new SqlConnection(connstring);
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            DataSet ds = new DataSet();
            da.Fill(ds, "employee");