Refreshing Crystal Report based on parameter values in asp.net

After searching in Internet and helping by Google, I can solve my problem. The problem is, I have button to generate a report and some fields to set paramater values in Crystal Repor. When I click the button it will generate report base paramater values, but when I change a or some fields for the parameter values and then click button to generate report, there is no changing. It still showed the first or the old values.

And the solution for that is, I add CrystalReportViewer1.ParameterFieldInfo.Clear(); in my button event before call generate report function.

protected void btnGenerate_Click(object sender, ImageClickEventArgs e)
{
CrystalReportViewer1.ParameterFieldInfo.Clear();
string message = GenerateReport();
if (message != string.Empty)
Util.ShowMessage(Page, “Failed to generate report, message : ” + message);
}

My reference is http://www.aspdotnet-suresh.com/2012/01/crystal-report-not-refreshing-based-on.html