Example of querying a large amount of data in ASP. NET by PAGE

Paging is also the most frequently asked question. It is also very basic and practical.

There are a lot of paging code on the Internet. If there is no front-end, there is no back-end, there is no front-end, there is no control, or a lot of SQL code, people do not know how to use. Strive for the simplest and easiest to understand. The three-tier architecture won't be involved. Download one by yourself. If it is access, use this sqlhelper [url = http://hi.csdn.net/link.php? Url = http://blog.csdn.net/zzxap?http://hi.csdn.net/link.php? Url = http://blog.csdn.net/zzxap#/url#if it is MSSQL, use this sqlhelper [url = Alipay zzxap@hotmail.com [code = HTML] Front-end if you use the gridview, replace repeater with the gridview. Same .. <Form ID = "frm01" Action = "" method = "Post" runat = "server"> <asp: scriptmanager id = "scriptmanager1" runat = "server"> </ASP: scriptmanager> <asp: updatepanel id = "updatepanel1" runat = "server"> <contenttemplate> <Div id = "center-top"> <Div class = "Fon"> intermediate 1 </div> </div> <Div id = "center-content_Default2"> <asp: repeater runat = "server" id = "mainlist"> <itemtemplate> <Div id = "pic-out"> <li class = "pic-a"> eval ("Product_type "). tostring () </LI> <li class = "pic-B"> eval ("product_desc "). tostring () </LI> <li> price <% # eval ("price") %> </LI> </div> </itemtemplate> </ASP: repeater> </div> <Div style = "padding-top: 10px; text-align: Center"> & nbsp; Total <asp: label id = "lpagecount" forecolor = "# ff0000" runat = "server"> </ASP: Label> labels <asp: label id = "ltotalcount" forecolor = "# ff0000" runat = "server"> </ASP: Label> note <asp: linkbutton id = "fi Stpage "runat =" server "commandname =" 0 "onclick =" pager_click "> first published </ASP: linkbutton> <asp: linkbutton id = "prevpage" runat = "server" commandname = "Prev" onclick = "pager_click"> previous cursor </ASP: linkbutton> <asp: linkbutton id = "nextpage" runat = "server" commandname = "Next" onclick = "pager_click"> next cursor </ASP: linkbutton> <asp: linkbutton id = "lastpage" runat = "server" commandname = "last" onclick = "pager_click"> tail cursor </ASP: linkbutton> first <Asp: Label id = "lcurrentpage" forecolor = "# ff0000" runat = "server"> </ASP: Label> Labels & nbsp; labels to the <asp: textbox id = "gotopage" width = "30px" runat = "server" autopostback = "true" maxlength = "5"> </ASP: textbox> condition <asp: label style = "position: absolute" id = "msgbox" runat = "server" forecolor = "red" bordercolor = "red"> </ASP: label> </div> </contenttemplate> </ASP: updatepanel> </form> [/Code] [code = C #] using system; using entity E M. data; using system. configuration; using system. web; using system. web. security; using system. web. ui; using system. web. UI. webcontrols; using system. web. UI. webcontrols. webparts; using system. web. UI. htmlcontrols; using system. data. oledb; using system. text; using Microsoft. applicationblocks. data; public partial class _ default: system. web. UI. page {string strpage = ""; int pagecount = 0; int reccount = 0; int Cu Rrentpage = 0; int current = 0; int pages = 0; int jumppage = 0; // jump to the page where the number of records is displayed. Int pagesize = 20; // each page displays 20 records: String product_type = ""; string type = ""; string headid = ""; Private Static int pageindex = 1; Private Static int pagecounts = 1; private Static int jumppages = 1; protected void page_load (Object sender, eventargs e) {# region receives parameters passed from the query page. If (request. querystring ["product_type"]! = NULL) {product_type = server. urldecode (request. querystring ["product_type"]. tostring () ;}if (request. querystring ["type"]! = NULL) {type = server. urldecode (request. querystring ["type"]. tostring () ;}# endregion // headid = request. querystring ["headid"]; If (! Ispostback) {// ------------------------------------------------------------- reccount = calc (); // calculate the total number of records pagecount = reccount/pagesize + overpage (); // calculate the total number of pages pagecounts = reccount/pagesize-modpage (); If (! String. isnullorempty (strpage) {// set the current page to return pageindex = int. parse (strpage);} else {pageindex = 1; // set the current page to 11 // session ["curpage"] = 1;} jumppages = pagecount; lpagecount. TEXT = pagecount. tostring (); // the total number of pages ltotalcount. TEXT = reccount. tostring (); // The total number of records if (reccount <= pagesize) {gotopage. enabled = false;} else {gotopage. enabled = true ;}//------------------------------------------------------- ------ Getmaindata (); // bind data }}# region "calculates the total number of rows" Public int overpage () {// calculates the remainder int pages = 0; if (reccount % pagesize! = 0) {pages = 1;} else {pages = 0;} return pages;} public int modpage () {// calculate the remainder int pages = 0; if (reccount % pagesize = 0 & reccount! = 0) {pages = 1;} else {pages = 0;} return pages;} public int calc () {// calculate the total data dataset DS = new dataset (); stringbuilder ass = new stringbuilder ("select count (ID) from m_product where 1 = 1 "); // If a query parameter is input, the total number of query results is calculated. If (type! = NULL & type! = "") {Ass. append ("and [type] =" + type. Replace ("'", "") + "");} If (product_type! = NULL & product_type! = "") {Ass. append ("and product_type =" + product_type.replace ("'", "") + "");} string BSS = ass. tostring (); int recordcount = 0; DS = sqlhelper. executedataset (sqlhelper. conn, commandtype. text, BSS); recordcount = int32.parse (Ds. tables [0]. rows [0] [0]. tostring (); // recordcount = 10; If (recordcount <pagesize) {fistpage. enabled = false; prevpage. enabled = false; nextpage. enabled = false; lastpage. Enabled = false;} else {fistpage. enabled = true; prevpage. enabled = true; nextpage. enabled = true; lastpage. enabled = true;} return recordcount;} # endregion # region "flip" Public void pager_click (Object sender, eventargs e) {currentpage = (INT) pageindex; pages = (INT) pagecounts; string Arg = (linkbutton) sender ). commandname. tostring (); Switch (ARG) {Case "Next": // URL paging is supported for the next page. If (currentpage <pages + 1) {currentpage = currentpage + 1;} break; Case "Prev": // previous page if (currentpage! = 1) {currentpage-= 1;} break; Case "last": // The last page currentpage = pages + 1; break; default: // homepage currentpage = 1; break;} // control the availability of the page flip button based on the number of pages. If (currentpage> 1) {fistpage. enabled = true; prevpage. enabled = true;} else {fistpage. enabled = false; prevpage. enabled = false;} If (currentpage = pages + 1) {nextpage. enabled = false; lastpage. enabled = false;} else {nextpage. enabled = true; Las Tpage. enabled = true;} pageindex = currentpage; // obtain the changed page number. // session ["curpage"] = currentpage; // The user returns to the current page getmaindata ();} // the page to which protected void gotopage_textchanged (Object sender, system. eventargs e) {string ASD = This. gotopage. text. trim (). tostring (); jumppage = (INT) jumppages; If (string. isnullorempty (ASD) {alert ("out of page range"); return;} If (int32.parse (gotopage. text)> jumppage | int 32. parse (gotopage. text) <= 0 | string. isnullorempty (ASD) {alert ("out of page range"); // The number of pages exceeds the return;} else {int inputpage = int32.parse (gotopage. text. tostring (); pageindex = inputpage; // session ["curpage"] = inputpage; getmaindata (); // bind the dataset }}# endregion public void alert (string RTT) {// display the prompt information // system. web. UI. scriptmanager. registerclientscriptblock (updatepanel1, this. getType (), "ajaxmsgbo X "," alert ('"+ RTT +"'); ", true);} private void getmaindata () {currentpage = (INT) pageindex; // obtain the current page pages = (INT) pagecounts; // obtain the total number of pages lcurrentpage. TEXT = currentpage. tostring (); int pagesize2 = pagesize * (currentpage-1) + 1; if (type! = NULL & product_type! = NULL) // if the phone number {// The number of function parameters is incorrect in the query expression 'isnull (max (XX. ID), 0. // The select clause contains a reserved word, spelling error or missing parameter, or incorrect punctuation. // The core statement of paging determines the performance of row_number. You can also change the following statement to a stored procedure. Stringbuilder SQL = new stringbuilder ("select top" + pagesize + "* From m_product a"); SQL. append ("where. [ID]> (select max (XX. [ID]) from (select top "+ pagesize2 +" [ID] From m_product where 1 = 1 "); If (type! = NULL & type! = "") {SQL. append ("and [type] =" + type. Replace ("'", "") + "");} If (product_type! = NULL & product_type! = "") {SQL. append ("and product_type =" + product_type.replace ("'", "") + "");} SQL. append ("order by [ID]) xx)"); If (type! = NULL & type! = "") {SQL. append ("and A. [type] =" + type. Replace ("'", "") + "");} If (product_type! = NULL & product_type! = "") {SQL. append ("and. product_type = "+ product_type.replace (" '"," ") +" ");} SQL. append ("order by. [ID] "); mainlist. datasource = sqlhelper. executedataset (sqlhelper. conn, commandtype. text, SQL. tostring (); mainlist. databind () ;}} [/Code]