How can I pass parameter to Reportviewer?

问题

I am trying to create report for TOP (according to user provide say 10,100,200..) products. I am 90% success with it. Now, I am finding difficulties to show this numbers to Report header. So, my report header is saying Top Products, now I want to make this dynamic, saying Top 100 Products, Top 200 Products.

I AM USING VS 2008.

For this, I created parameter in ReportViewer. I tried this code in Page_Load event ;

 protected void Page_Load(object sender, EventArgs e)
{
    ReportDataSource rds = new ReportDataSource("SP_GetProductsbySales_DataSet");
    //ReportViewer1.ServerReport.ReportPath = "Report1.rdlc";
    ReportViewer1.LocalReport.ReportPath = "Report1.rdlc";
    ReportParameter[] param = new ReportParameter[1];
    param[0] = new ReportParameter("top", "100");

    ReportViewer1.ServerReport.SetParameters(param);
    ReportViewer1.ServerReport.Refresh();
}

but getting error saying : The source of the report definition has not been specified.

How can I accomplish this one? I tried to google as well as watched some videos, but still I am not getting any idea.

Thanks.

回答1:

Please set data source

       ReportViewer1.LocalReport.DataSources.Clear();

       ReportViewer1.LocalReport.DataSources.Add(rds);

回答2:

You can set an expression in your report to show the value.

The expression would be as follows:

="Top " & Parameters!top.Value & " Products"

来源：https://stackoverflow.com/questions/15060213/how-can-i-pass-parameter-to-reportviewer