ExecuteScalar: Connection property has not been initialized

Question

I've tried lots of suggestions on the Internet in order to run executeScalar, but I get the error ExecuteScalar: Connection property has not been initialized. My INSERT query is working fine, the problem is with executeScalar.

conn.Open();
SqlCommand cmd = new SqlCommand(
    "INSERT INTO Products (Product_Name,Product_BarCode,Product_CP,Product_SP,
                           Product_Countainer,Product_Pcs,Product_MFGDate,
                           Product_ExpiryDate,Product_Grade)
     Values ('" + Name.Text + "','" + BarCode.Text + "','" + CostP.Value + "','" + 
             SellingP.Value + "','" + Countainer.Value + "','" + Pcs.Value + "','" + 
             MfgDate.Value + "','" + ExpDate.Value + "','" + Grade.SelectedItem + "')", 
     conn);
cmd.ExecuteNonQuery();
conn.Close();

conn.Open();
cmd.Connection = conn;
cmd = new SqlCommand("SELECT SUM(Product_CP) FROM Products AS Amount");
Amount = (double)cmd.ExecuteScalar();
MessageBox.Show(Amount.ToString());
conn.Close();

Answer 1

cmd = new SqlCommand(...);

As the error clearly states, this command doesn't have a connection.