How to set the parameter in Web API Controller

[NonAction]
public void OnReportLoaded(ReportViewerOptions reportOption)
{
    List<BoldReports.Web.ReportParameter> userParameters = new List<BoldReports.Web.ReportParameter>();
    userParameters.Add(new BoldReports.Web.ReportParameter()
    {
        Name = "SalesOrderNumber",
        Values = new List<string>() { "SO50756" }
    });
    reportOption.ReportModel.Parameters = userParameters;
}