C#連接數據庫是編寫的SqlHelper

    static class SqlHelper

        {

            private static string connStr = ConfigurationManager.ConnectionStrings["dbConStr"].ConnectionString;


        //封裝方法的原則：把不變的放在方法里 變化的放到參數列表中  

        public static int ExecuteNonQuery(string sql, params SqlParameter[] parameters)  
        {  
            using (SqlConnection coon = new SqlConnection(connStr))  
            {  
                coon.Open();  
                using (SqlCommand cmd = coon.CreateCommand())  
                {  
                    cmd.CommandText = sql;  
                    cmd.Parameters.AddRange(parameters);  
                    return cmd.ExecuteNonQuery();  
                }  
            }  
        }  

        public static object ExecuteScalar(string sql, params SqlParameter[] parameters)  
        {  
            using (SqlConnection coon = new SqlConnection(connStr))  
            {  
                coon.Open();  
                using (SqlCommand cmd = coon.CreateCommand())  
                {  
                    cmd.CommandText = sql;  
                    cmd.Parameters.AddRange(parameters);  
                    return cmd.ExecuteScalar();  
                }  
            }  
        }  


        //由于查詢的比較小  所以 可以直接用Table  
        public static DataTable ExecuteDataTable(string sql, params  SqlParameter[] parameters)  
        {  
            using (SqlConnection coon = new SqlConnection(connStr))  
            {  
                coon.Open();  
                using (SqlCommand cmd = coon.CreateCommand())  
                {  
                    cmd.CommandText = sql;  
                    cmd.Parameters.AddRange(parameters);  

                    DataSet dataset = new DataSet();  
                    SqlDataAdapter adapter = new SqlDataAdapter(cmd);  
                    adapter.Fill(dataset);  
                    return dataset.Tables[0];  
                }  
            }  
        }  </pre>