public partial class _Default : System.Web.UI.Page
       {
           protected void Page_Load(object sender, EventArgs e)
           {
                //从web.config文件中获取数据库连接字符串
               string ConnStr = ConfigurationManager.
                  ConnectionStrings["StudentConnectionString"].ConnectionString;
                //使用using语句块，可以达到自动释放连接的作用
               using (SqlConnection conn = new SqlConnection(ConnStr))
               {
                    //创建强类型的数据集对象
                   StudentInfoDataSet ds = new StudentInfoDataSet();
                    创建DepartName表对应的TableAdapter对象
                   DepartNameTableAdapter depart = new DepartNameTableAdapter();
                   depart.Connection=conn;
                    //填充DepartName表
                   depart.Fill(ds.DepartName);      //标记1
                    //创建StudentInfo表对应的TableAdapter对象
                   StudentInfoTableAdapter stu = new StudentInfoTableAdapter();
                   stu.Connection=conn;
                    //填充StudentInfo表
                   stu.Fill(ds.StudentInfo);       //标记2
                  
                    //创建SqlDataReader对象，用于填充数据集
                   SqlDataAdapter ad = new SqlDataAdapter();
                   ad.SelectCommand = new SqlCommand();
                   ad.SelectCommand.Connection = conn;
                   / /获取查询SQL语句
                   ad. = "select NO,SName,Sex,Birthday,"
                  +"DepartName.DName,Score from StudentInfo Inner Join DepartName"
                   +" On
                    //填充数据集
                   ad.Fill(ds);         //标记3
                    //创建ReportDocument对象，与水晶报表中的数据交互
                   ReportDocument doc = new ReportDocument();
                    //加载水晶报表
                   doc.Load(Server.MapPath("CrystalReportStudent.rpt"));
                   //设置报表的数据源
                  doc.SetDataSource(ds);
                    //设置报表的作者
                   doc.SummaryInfo.ReportAuthor = "Mr Lee";
                    //设置报表的标题
                   doc.SummaryInfo.ReportTitle = "学生信息表";
                    //使用CrystalReportViewer对象显示水晶报表
                   this.CrystalReportViewer1.ReportSource = doc;
                    //绑定数据
                   this.CrystalReportSource1.DataBind();
               }
           }
       }
   }
为何标记1和标记2那里填充数据表时不需要像填充标记3一样要设置查询SQL语句才可以填充，数据从何而来？还有为什么标记1和标记2已经把数据集ds填充了标记3那里还要再填充一次？可能是我对强类型数据集和强类型数据表的关系和概念不够熟悉，若能举例说明更好，当然例子要简单通俗

这里变得好冷清啊

还不错，不过我看不懂，我刚学