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;

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

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            using (SqlConnection conn = new SqlConnection("Data Source=.; Initial Catalog=Student;User ID=sa;Password=sa"));
            {
                conn.Open();
            }
        }
    }
}
conn一直提示不存在名称 改为别的也不行

private void button1_Click(object sender, RoutedEventArgs e)
{
    using (SqlConnection conn = new SqlConnection("Data Source=.; Initial Catalog=Student;User ID=sa;Password=sa"));
    {
        conn.Open();
    };
}
敢不敢把红色的分号去掉，换到紫色的位置

using行末的分号去掉就行了