黑马程序员 自己编写SqlHelper
class SqlHelper { //使用长度可变参数来简化 public static int ExecuteNonQuery(string sql,params SqlParameter[] parameters) { using (SqlConnection conn = new SqlConnection(connStr)) { conn.Open(); using (SqlCommand cmd = conn.CreateCommand()) { cmd.CommandText = sql; //foreach (SqlParameter param in parameters) //{ // cmd.Parameters.Add(param); //} cmd.Parameters.AddRange(parameters); return cmd.ExecuteNonQuery(); } } } public static object ExecuteScalar(string sql, params SqlParameter[] parameters) { using (SqlConnection conn = new SqlConnection(connStr)) { conn.Open(); using (SqlCommand cmd = conn.CreateCommand()) { cmd.CommandText = sql; cmd.Parameters.AddRange(parameters); return cmd.ExecuteScalar(); } } } //只用来执行查询结果比较少的sql public static DataTable ExecuteDataTable(string sql, params SqlParameter[] parameters) { using (SqlConnection conn = new SqlConnection(connStr)) { conn.Open(); using (SqlCommand cmd = conn.CreateCommand()) { cmd.CommandText = sql; cmd.Parameters.AddRange(parameters); SqlDataAdapter adapter = new SqlDataAdapter(cmd); DataSet dataset = new DataSet(); adapter.Fill(dataset); return dataset.Tables[0]; } } } }