ExecuteNonQuery: Connection property has not been initialized. C# .Net

I'm trying to save the textbox values in sql table column but i got an error as ExecuteNonQuery: Connection property has not been initialized.

My code is 

SqlConnection con = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\desktop\texmas\App_Data\texsasDB.mdf;Integrated Security=True;User Instance=True");
        con.Open();
        SqlCommand cmd=new SqlCommand("insert into registration values('"+txt_name.Text+"','"+txt_mobile.Text+"','"+txt_email.Text+"','"+txt_qualification.Text+"','"+txt_yearofpassing.Text+"','"+FileUpload1.ToString()+"')");
        cmd.ExecuteNonQuery();
        con.Close();

please suggest me