Apply Parameter Field using Crystal Report

Design View of the Page
<CR:CrystalReportViewer ID="CrystalReportViewer1" runat="server" AutoDataBind="true" />
Code Behind of the Page
ReportDocument objReportDocument;
Page Load
protected void Page_Load(object sender, EventArgs e)
{
if (Request.QueryString["EmployeeID"] != null)
{
string reportPath = Server.MapPath("ProgramaticallyReport.rpt");
objReportDocument = new ReportDocument();
ParameterDiscreteValue objDiscreteValueEmployeeID = new ParameterDiscreteValue();
string objCustomerID = (Convert.ToString(Request.QueryString["EmployeeID"]));
objDiscreteValueEmployeeID.Value = objCustomerID;
//ParameterDiscreteValue objDiscreteValueLastMonth = new ParameterDiscreteValue();
//DateTime objDate2 = (System.Convert.ToDateTime(Request.QueryString["Date2"]));
//objDiscreteValueLastMonth.Value = objDate2;
ParameterField objParameterField = new ParameterField();
objParameterField.Name = "EmpID";
objParameterField.CurrentValues.Add(objDiscreteValueEmployeeID);
//objParameterField.CurrentValues.Add(objDiscreteValueLastMonth);
ParameterFields objParameterFields = new ParameterFields();
objParameterFields.Add(objParameterField);
objReportDocument.Load(reportPath);
objReportDocument.SetDataSource(GetCustomer());
CrystalReportViewer1.ParameterFieldInfo = objParameterFields;
CrystalReportViewer1.ReportSource = objReportDocument;
}
else
{
Exception objException = new Exception();
lblMessage.Text = objException.Message;
}
GetCustomer Dataset Method
public DataSet GetCustomer()
{
string objCustomerID = (Convert.ToString(Request.QueryString["EmployeeID"]));
SqlParameter objParameter = new SqlParameter();
SqlCommand objCommand = new SqlCommand();
SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString);
SqlDataAdapter da = new SqlDataAdapter("SELECT EmployeeID,FirstName, LastName, City, Country " +
"FROM Employees where EmployeeID=@EmployeeID", conn);
da.SelectCommand.Parameters.Add(new SqlParameter("@EmployeeID", objCustomerID));
da.SelectCommand.Parameters["@EmployeeID"].Value = objCustomerID;
DataSet ds = new DataSet();
da.Fill(ds, "Employees");
return ds;
}