How to reset crystal report using dataset xsd in winform c#

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C#3.5

hello ! here ,I want to print a crystal report on invoice no.. When i submit product details,it prints on that invoice number but, here is the problem that when i submitted my next product detail
it could not print crystal report on present parameter value means invoice number, it added all current details to the previous details and show previous invoice number.
Please! Give provide a solution .I am not habitual with windows form.Its a Sale invoice project which is my first project.
here is some parts of code:

private void Report_Load(object sender, EventArgs e)
{


CrystalReport1 cryRpt = new CrystalReport1();

ParameterField paramField = new ParameterField();
paramField.Name = "BillNo";
ParameterDiscreteValue paramDiscreteValue = new ParameterDiscreteValue();
paramDiscreteValue.Value = a;
paramField.CurrentValues.Add(paramDiscreteValue);
ParameterFields paramFields = new ParameterFields();
paramFields.Add(paramField);
crystalReportViewer1.ParameterFieldInfo = paramFields;

}