如何在SQL CE数据库中添加数据

Question

使用方法如下 public void opensql()        {            //SqlCommand cm = new System.Data.SqlClient.SqlCommand();            //SqlConnection cn = new SqlConnection();            SqlCeCommand cm = new SqlCeCommand();            SqlCeConnection cn = new SqlCeConnection();            //cn.ConnectionString = "Data Source=symbol.sdf";            //cn.ConnectionString = "server=JC91109;uid=sa;pwd=sa;database=symbol";            string appPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().GetName().CodeBase.ToString());            string dbcStr = @"Data Source =" + appPath.Replace(@"\\", @"\") + @"\symbol.sdf";            cn.ConnectionString = ""+dbcStr+"";            cn.Open();            cm.Connection = cn;        } private void button1_Click(object sender, EventArgs e)        {            opensql();            cm.CommandText = "insert into scan(barcode) values('123')";            cm.ExecuteNonQuery();            SqlDataReader rs = cm.ExecuteReader();         } 在PDA中运行报错，在cm.CommandText = "insert into scan(barcode) values('123')";处显示没有NEW对象的实例。 在PDA的程序当前目录下有SYMBOL.SDF文件并有表SCAN.