新建一個“連線”按鈕，取名btSql_Connect_Click，在按鈕Click事件中寫如下程式碼:

//連線SQL Server的test資料庫
            //string connectionString = "Data Source=localhost;Database=test;uid=sa;pwd=xxx";
            string connectionString = "Data Source=localhost;Database=test;Integrated Security=true";
            string sql = "select count(*) from Student";
            SqlConnection connection = new SqlConnection(connectionString);
            if (connection != null)
            {
                connection.Open();
                //SqlCommand物件,執行操作資料錄的命令
                SqlCommand command = new SqlCommand(sql, connection);
                int totalcount = Convert.ToInt32(command.ExecuteScalar());
                MessageBox.Show("test表中共有" + totalcount + "條資料");
                connection.Close();
            }
            else
            {
                MessageBox.Show("連線SQL Server失敗!");
            }