Crystal Report ---"ParameterField.Add" throw NotSupportedexception

[Worrow]

Here is the code:

 

ReportDocument rptShippingList;

rptShippingList = new ReportDocument();

rptShippingList.Load(Application.StartupPath+ "\\FullCartonPickingInstructionList.rpt");

ParameterDiscreteValue y = new ParameterDiscreteValue();

y.Value = "Transfer";

ParameterValues x = new ParameterValues();

x.Add(y);

ParameterField param = new ParameterField();

param.Name = "Transfer";

param.CurrentValues = x;

rptShippingList.ParameterFields.Add(param); <---Problem:confused:

 

Everything is fine until the last line. I got a NotSupportedexception which I have not idea what the problem is :( I have already search the web but no one seems to have such problem! Anyone know what's going on here?

 

Thanks in advance!

[Worrow]

Well, the problem is I need to set the datasource of the report before adding any parameter. :o