Display data with in grid

When I click on job tittle it should be redirect to next page with job description,I don't know what is going wrong but after selecting the job tittle am getting the null value,I don't know what is going wrong?so can any one help me my code is like

In Stored Procedure:

create procedure USP_Getdetails

@RequirementID int

begin

select distinct PositionTittle,JobDescription from Tbl_RequirementModule where RequirementID=@RequirementID

end

In.DAL:

public DataSet GetDdata(int RequirementID)

{

SqlConnection con = dbcon.OpenCoonection();

SqlCommand cmd = new SqlCommand("USP_GetJobDescriptionGrid", con);

cmd.CommandType = CommandType.StoredProcedure;

SqlDataAdapter da = new SqlDataAdapter(cmd);

cmd.Parameters.AddWithValue("@RequirementID", RequirementID); // If I select position tittle also then am getting null value why??what mistke am doing??

DataSet ds = new DataSet();

da.Fill(ds);

dbcon.CloseConnection();

return ds;

}

In.cs:

public void GetData()

{

int ReqID = Convert.ToInt32(Session["RegId"]); // Am accessing session variable

JobAlpplingGrid.DataSource = objjob.GetDdata(ReqID);

JobAlpplingGrid.DataBind();

}