ช่วยดู error ให้หน่อย ครับ (เป็น code แบ่ง หน้า ใน datalist)... Both DataSource and DataSourceID are defined on...

private void ItemsGet()
       {

           string strconn = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].ToString();
           SqlConnection conn = new SqlConnection(strconn);

           SqlDataAdapter da = new SqlDataAdapter("select * from product", conn);
           DataSet ds = new DataSet();
           da.Fill(ds, "product");
           

           PagedDataSource objPds = new PagedDataSource();
           objPds.DataSource = ds.Tables["product"].DefaultView;
           objPds.AllowPaging = true;
           objPds.PageSize = 3;
           objPds.CurrentPageIndex = CurrentPage;

           lblCurrentPage.Text = "Page: " + (CurrentPage + 1).ToString() + " of " + objPds.PageCount.ToString();

           cmdPrev.Enabled = !objPds.IsFirstPage;
           cmdNext.Enabled = !objPds.IsLastPage;


           DataList1.DataSource = objPds;
           DataList1.DataBind();
       }



       public int CurrentPage
       {
           get
           {
               object o = this.ViewState["_CurrentPage"];
               if (o == null)
                   return 0; // default to showing the first page
               else
                   return (int)o;
           }

           set
           {   this.ViewState["_CurrentPage"] = value;      }

       }

       protected void cmdPrev_Click(object sender, System.EventArgs e)
       {
           CurrentPage -= 1;
           ItemsGet();

       }

       protected void cmdNext_Click(object sender, System.EventArgs e)
       {
           CurrentPage += 1;
           ItemsGet();
       }