Solve the Asp.Net Dynamically Passed Parameters?

-----------------> Pass The Parameters to DropDown List

protected void Page_Load(object sender, EventArgs e)
{

if (!IsPostBack)
{
DropDownList1.AppendDataBoundItems = true;
String strConnString = ConfigurationManager
.ConnectionStrings["myDemo"].ConnectionString;
String strQuery = "select eno,CustomerName from Customer";
SqlConnection con = new SqlConnection(strConnString);
SqlCommand cmd = new SqlCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = strQuery;
// cmd.Parameters.Add("@eno", Convert.ToInt32(eno));
cmd.Connection = con;
try
{
con.Open();
DropDownList1.DataSource = cmd.ExecuteReader();
DropDownList1.DataTextField = "CustomerName";
DropDownList1.DataValueField = "eno";

DropDownList1.DataBind();

}
catch (Exception ex)
{
throw ex;
}
finally
{
con.Close();
con.Dispose();
}
}

---->This Paramater values passed to the Report Viewer getting error

ReportViewer1.ProcessingMode = ProcessingMode.Remote;
ReportViewer1.ServerReport.ReportServerUrl = new Uri("http://ARB4:80/ReportServer");
ReportViewer1.ServerReport.ReportPath = "/ssrs reports/Chart-Reports";
List<ReportParameter> parameters = new List<ReportParameter>();
parameters.Add(new ReportParameter("CustomerName", DropDownList1.SelectedItem.Text));

ReportViewer1.ServerReport.SetParameters(parameters);
ReportViewer1.ProcessingMode = ProcessingMode.Remote;
ReportViewer1.ShowParameterPrompts = false;
ReportViewer1.ShowPromptAreaButton = false;
ReportViewer1.ShowReportBody = true;

ReportViewer1.ServerReport.Refresh();