开发PDA的程序时发生错误"路径无效。请检查数据库的目录。"

Question

在本机上用模拟器运行程序时发生错误报“路径无效。请检查数据库的目录”。

symbol.sdf在程序的目录下

打开数据库的方法如下：

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";
            cn.ConnectionString = "data source=symbol.sdf";
            cn.Open();
            cm.Connection = cn;
        }