DataTable动态增多一列并赋值-调用应用程序配置文件-带存储过程的SqlHelper类

DataTable动态增加一列并赋值-调用应用程序配置文件-带存储过程的SqlHelper类

DataTable   dt  =  new  DataTable();

增加列：

dt.columns.add("username",Type.GetType("system.String");

dt.columns.add("age",Type.GetType("System.Int32");

赋值：

dt.Rows.add(new object[]{"黄忠",22});

在C#中如何调用应用程序配置文件(app.conifg)中的连接字符串?

如果是connectionStrings，用ConfigurationManager.ConnectionStrings["add的name"].ConnectionString;

如果是appSettings，用ConfigurationManager.AppSettings["add的key"]

带存储过程的SqlHelper类

    public static class SqlHelper
    {
        private readonly static string strcon = ConfigurationManager.ConnectionStrings["sql"].ConnectionString;
        public static int ExeucteNonQuery(string sql, CommandType type, params SqlParameter[] pms)
        {
            using (SqlConnection con = new SqlConnection(strcon))
            {
                using (SqlCommand cmd = new SqlCommand (sql,con))
                {
                    cmd.CommandType = type;
                    if (pms != null)
                    {
                        cmd.Parameters.AddRange(pms);
                    }
                    con.Open();
                    return cmd.ExecuteNonQuery();
                }
            }
        }
        public static object ExecuteScalary(string sql, CommandType type, params SqlParameter[] pms)
        {
            using (SqlConnection con = new SqlConnection(strcon))
            {
                using (SqlCommand cmd = new SqlCommand(sql, con))
                {
                    cmd.CommandType = type;
                    if (pms != null)
                    {
                        cmd.Parameters.AddRange(pms);
                    }
                    con.Open();
                    return cmd.ExecuteScalar();
                }
            }
        }
        public static SqlDataReader ExecuteReader(string sql, CommandType type, params SqlParameter[] pms)
        {
            SqlConnection con = new SqlConnection(strcon);
            using (SqlCommand cmd = new SqlCommand(sql,con))
            {
                cmd.CommandType = type;
                if (pms != null)
                {
                    cmd.Parameters.AddRange(pms);
                }
                con.Open();
                return cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }
        }
        public static DataTable GetTable(string sql, CommandType type, params SqlParameter[] pms)
        {
            using (SqlDataAdapter adapter = new SqlDataAdapter(sql,strcon))
            {
                adapter.SelectCommand.CommandType = type;
                if (pms != null)
                {
                    adapter.SelectCommand.Parameters.AddRange(pms);

                }
                DataTable table = new DataTable();
                adapter.Fill(table);
                return table;

            }
        }
    }

今天面试，发现自己有太多的东西，都只是一知半解。

为美好生活，无论加艰难，都不能认输。