配置文件链接字符串

namespace WpfApplication2
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
        //连接字符串
        string constr = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;
        private void button1_Click(object sender, RoutedEventArgs e)
        {
            using (SqlConnection conn = new SqlConnection(constr))
            {
                conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = "select waterwork from Table_1 where othersnum=@num";
                    cmd.Parameters.Add(new SqlParameter("@num", textBox1.Text));
                    using (SqlDataReader reader = cmd.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            string work = reader.GetString(0);
                            MessageBox.Show(work);
                        }
                    }
                }
            }
        }

        private void btnDataSet1_Click(object sender, RoutedEventArgs e)
        {
            using(SqlConnection conn=new SqlConnection (constr))
            {
                using(SqlCommand cmd=conn.CreateCommand())
                {
                    cmd.CommandText = "select * from Table_1";
                    SqlDataAdapter adapter = new SqlDataAdapter(cmd);
                    DataSet dataset = new DataSet();
                    adapter.Fill(dataset);
                    //foreach(DataRow row in dataset.Tables[0].Rows)
                    //{
                    //    int waternum = (int)row["waterwork"];
                    //    MessageBox.Show(waternum.ToString());
                    //}
                    DataTable table = dataset.Tables[0];
                    DataRowCollection rows = table.Rows;
                    for (int i = 0; i < rows.Count;i++ )
                    {
                        DataRow r = rows[i];
                        string waternum = (string)r["waterwork"];
                        MessageBox.Show(waternum);
                    }
                }
            }
        }
    }
}

 App.config配置文件

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <connectionStrings>
    <add name="ConnStr" connectionString="Data Source=.;Initial Catalog=master;User ID=sa;Password=123456;"/>
  </connectionStrings>
</configuration>