class clsDyCrystalReportCore
    {
        /// <summary>
        /// 将传入的datatable转换成报表模板所需要的datatable
        /// 数据全部转换为string
        /// </summary>
        /// <param name="dt">来源表</param>
        /// <param name="tblName">各单表名称</param>
        /// <param name="fldsName">字段名称，以半角逗号分隔。</param>
        /// <returns>报表模板所需要的datatable</returns>

        public DataTable dtx(DataTable dt,String tblName,String fldsName)
        {

            String oneRow="";
            DataSet1.BigTatableDataTable dtx1 = new DataSet1.BigTatableDataTable();
            
            object[] obj = new object[dt.Columns.Count];
           //特别注意：所选择的表的列的数目需<=Bigtable的字段数目
            //请自行填写保护代码

            //先列名称写到每个表的第一行
            dtx1.Rows.Add(dtx1.NewRow());
            //第一行的第一列写表的名称
            dtx1.Rows[0][0] = tblName;
            //切割列名称字符串，写入第一行后面的位置
            for (int i = 0; i < fldsName.Split(new char[] { ',' }).Length; i++)
            {
                
                dtx1.Rows[0][i+1] = fldsName.Split(new char[] {','})[i];
            }

            //写入数据
            for (int i = 0; i <dt.Rows.Count ; i++)
            {

                dtx1.Rows.Add(dtx1.NewRow());
                //每一行的第一列，也就是f0，写入表名称。
                dtx1.Rows[i+1][0] = tblName; 
                //写数据
                for (int j = 0; j < dt.Columns.Count ; j++)
                {
                    oneRow = oneRow + "," + dt.Rows[i][j].ToString();
                    if (dt.Rows[i][j].ToString()=="" )
                        dtx1.Rows[i+1][j+1] = " "; 
                    else
                    dtx1.Rows[i+1][j+1] = dt.Rows[i][j].ToString();   
                }
               
            }
            return dtx1;
        }
    }

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Text;
using System.Windows.Forms;
using CrystalDecisions.Shared;
using CrystalDecisions.CrystalReports.Engine;
using CrystalDecisions.Windows.Forms;
using System.Data.OleDb;
namespace DyCrystalReportDemo
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
             String connstr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + System.Threading.Thread.GetDomain().BaseDirectory+ "bbtcrall.mdb" + ";";
            
            //打开数据库连接
             OleDbConnection cn = new OleDbConnection(connstr);
            
            DataTable dtxAll = new DataTable(); //容纳所有数据
            OleDbDataAdapter da = new OleDbDataAdapter();
            clsDyCrystalReportCore xCore = new clsDyCrystalReportCore();
            
            //注意各表的字段数目不能大于我们设定的最大数目！
            //请自行添加错误保护和对象释放代码

            //第1个表
            DataTable dt1 = new DataTable();
            DataTable dtx1 = new DataTable();   
            da = new OleDbDataAdapter("SELECT * From Test1_1", cn);
            da.Fill(dt1);
            dtx1 = xCore.dtx(dt1,"表1","编号,姓名,发信日期,其他");
            dtxAll.Merge(dtx1);


            //第2个表，注意，这个表可以从不同的数据源获取!
            //重新初始化
            dt1 = new DataTable();
            dtx1 = new DataTable();
            da = new OleDbDataAdapter("SELECT * From Test1_2", cn);
            da.Fill(dt1);
            dtx1 = xCore.dtx(dt1, "表2", "编号,姓名,入职日期,日期1,日期2");
            dtxAll.Merge(dtx1);

           
            //第3个表，注意，这个表可以从不同的数据源获取!
            //重新初始化
            dt1 = new DataTable();
            dtx1 = new DataTable();
            da = new OleDbDataAdapter("SELECT * From Test_4", cn);
            da.Fill(dt1);
            dtx1 = xCore.dtx(dt1, "表3", "年份,地区,指标,最大值,最小值");
            dtxAll.Merge(dtx1);

            
            ReportDocument myReport = new ReportDocument();
            string reportPath = System.Threading.Thread.GetDomain().BaseDirectory + "crystalreport1.rpt";
            myReport.Load(reportPath);

            //绑定数据集

            myReport.SetDataSource(dtxAll);
           
            crystalReportViewer1.ReportSource = myReport;
            crystalReportViewer1.RefreshReport();
        }

    }
}