using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;

namespace ********
{
    public class DataSet
    {
        public DataTable CreatDataSet()
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("A");
            dt.Columns.Add("B");
            dt.Columns.Add("C");
            return dt;

        }
    }
}

ReportViewer viewer = new ReportViewer();
            viewer.PRocessingMode = ProcessingMode.Local;
            viewer.LocalReport.ReportEmbeddedResource = "***.Page.Report.Report1.rdlc";
            ReportDataSource rds_1 = new ReportDataSource("DataSet1", dtReport);//DataSet1為報表裏面的數據源名稱
            viewer.LocalReport.DataSources.Add(rds_1);

            ReportParameter rp1 = new ReportParameter("參數1","參數1的值" );//給參數賦值
            ReportParameter rp2 = new ReportParameter("參數2","參數2的值" );
            viewer.LocalReport.SetParameters(new ReportParameter[] {rp1, rp2 });

            Warning[] warnings;
            string[] streamids;
            string mimeTyPE = string.Empty;
            string encoding = string.Empty;
            string extension = string.Empty;

            byte[] bytes = viewer.LocalReport.Render("Excel", null, out mimeType, out encoding, out extension, out streamIds, out warnings);
            //Excel ,PDF ,Word 等格式
            // Now that you have all the bytes representing the PDF report, buffer IT and send it to the client.
            Response.Buffer = true;
            Response.Clear();
            Response.ContentType = mimeType;
            Response.AddHeader("content-disposition", "attachment; filename=1_" + DateTime.Now.ToString("yyyyMMddhhssmm") + "" + "." + extension);
            Response.BinaryWrite(bytes); // create the file
            Response.Flush(); // send it to the client to download

DataTable dt = new DataTable();//自己拼出數據源就可以
                ReportDataSource repDataSource = new ReportDataSource("DataSet1", dt);

                //*設置報表參數,并顯示
                this.rpResut.LocalReport.ReportEmbeddedResource = "***.Page.Report.Report1.rdlc"";
                this.rpResut.LocalReport.DataSources.Clear();
                this.rpResut.LocalReport.DataSources.Add(repDataSource);
                 ReportParameter rp1 = new ReportParameter("參數1","參數1的值" );//給參數賦值
                  ReportParameter rp2 = new ReportParameter("參數2","參數2的值" );

                this.rpResut.LocalReport.SetParameters(new ReportParameter[] {rp1, rp2 });
                this.rpResut.DataBind();
                this.rpResut.LocalReport.Refresh();