Output Parameters In SQL Sp's

Hi everyone, can anyone help me please

I have a stored procedure that works quite well and returns one of the following codes, 1 2 3 or 4 which is dependant on business criteria.  This sp works well and satsisfies all the criteria etc.

I am calling this SP in asp.net (c#) like this

        using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["blah"].ConnectionString))
        {            int? intSQLCheck = null;


            con.Open();
            SqlCommand cmd = new SqlCommand("check_values", con);
            cmd.CommandType = CommandType.StoredProcedure;

            cmd.Parameters.Add(new SqlParameter("@param_clothing_id", this.DropDownList2.SelectedValue.ToString()));
            cmd.Parameters.Add(new SqlParameter("@empNo", this.DropDownList1.SelectedValue.ToString()));
            cmd.Parameters.Add(new SqlParameter("@createdBy", this.txtEmpNo.Text.ToString()));
            cmd.Parameters.Add(new SqlParameter("@price", this.txtPrice.Text));
            cmd.Parameters.Add(new SqlParameter("@qty", this.txtQty.Text));
            //cmd.Parameters.Add(new SqlParameter("@returnValue", 0));
            cmd.Parameters.Add(new SqlParameter("@returnVal", 99));
            cmd.Parameters["@returnVal"].Direction = ParameterDirection.Output;


            cmd.ExecuteNonQuery();

 

What I would like to do know is use a variable intSqlCheck to hold the return value from the SP (and then do some processing of business logic using the variable)

Any ideas anyone please