名称frm在当前上下文中不存在。

public partial class frmProduct : Form
{

    SqlConnection cn = new SqlConnection();
    SqlCommand cm = new SqlCommand();
    DBConnection dbcon = new DBConnection();
    SqlDataReader dr;
    frmProductList flist;

    public frmProduct(frmProductList flist)
    {
        InitializeComponent();
        cn = new SqlConnection(dbcon.MyConnection());
      flist = frm; //Error on this line "frm"
    }