對(duì)于大量數(shù)據(jù)的查詢和展示使用分頁是一種不錯(cuò)的選擇,這篇文章簡要介紹下自己實(shí)現(xiàn)分頁查詢的思路。
分頁需要三個(gè)變量:數(shù)據(jù)總量、每頁顯示的數(shù)據(jù)條數(shù)、當(dāng)前頁碼。
//數(shù)據(jù)總量 int dataCount; //每頁顯示的數(shù)據(jù)條數(shù) int pageDataCount; int pageNumber;
根據(jù)數(shù)據(jù)總量和每頁顯示的數(shù)據(jù)條數(shù)計(jì)算出總頁數(shù),根據(jù)當(dāng)前頁碼和每頁顯示的數(shù)據(jù)條數(shù)計(jì)算出從數(shù)據(jù)庫中讀取數(shù)據(jù)的起始行號(hào)和結(jié)束行號(hào)。
//總頁數(shù) int pageCount = (int)Math.Ceiling(dataCount/ (pageDataCount* 1.0)); int startLine = (pageNumber - 1) * PageDataCount + 1; int endLine=startLine + PageDataCount - 1;
對(duì)于數(shù)據(jù)庫的查詢操作使用輕量級(jí)ORM框架Dapper來實(shí)現(xiàn),具體代碼如下:
protected IDbConnection CreateConnection() { IDbConnection dbConnection = new SqlConnection(ConnectionString); dbConnection.Open(); return dbConnection; } //獲取數(shù)據(jù)庫中數(shù)據(jù)的總條數(shù) public virtual int QueryDataCount(string tableName) { using (IDbConnection dbConnection = CreateConnection()) { var queryResult = dbConnection.Query<int>("select count(Id) from " + tableName); if (queryResult == null || !queryResult.Any()) { return 0; } return queryResult.First(); } } public virtual IEnumerable<T> RangeQuery<T>(string tableName, int startline, int endline) { if (string.IsNullOrEmpty(tableName)) { throw new ArgumentNullException("表名不得為空或null"); } if (startline <= 0) { throw new ArgumentOutOfRangeException("起始行號(hào)必須大于0"); } if (endline - startline < 0) { throw new ArgumentOutOfRangeException("結(jié)束行號(hào)不得小于起始行號(hào)"); } using (IDbConnection dbConnection = CreateConnection()) { var queryResult = dbConnection.Query<T>("select top " + (endline - startline + 1) + " * from " + tableName + " where Id not in (select top " + (startline - 1) + " Id from " + tableName + " order by Id desc) order by Id desc"); if (queryResult != null && queryResult.Any()) { return queryResult; } } return null; }
繪制分頁按鈕
在App_Code文件夾中添加PageHelper.cshtml文件封裝繪制按鈕的代碼,這里需要注意一點(diǎn),使用VS發(fā)布站點(diǎn)時(shí)App_Code文件夾中的文件不會(huì)被打包,需要手動(dòng)拷貝App_Code文件夾中的文件到站點(diǎn)中。
@* amount:數(shù)據(jù)總數(shù),count:每頁顯示的數(shù)據(jù)條數(shù),redierctUrl點(diǎn)擊按鈕時(shí)的跳轉(zhuǎn)鏈接 頁面上需引用:bootstrap.min.css *@ @helper CreatePaginateButton(int amount, int count, string redirectUrl) { <div id="pagenumber" style="position:fixed;bottom:-15px;text-align:center;width:84%"> <nav style="text-align:center"> <ul class="pagination"> <li><a href="@redirectUrl/1" rel="external nofollow" >首頁</a></li> @{ int pageNumber = (int)Math.Ceiling(amount / (count * 1.0)); pageNumber = pageNumber < 1 ? 1 : pageNumber; //頁面上顯示的按鈕數(shù)目(不計(jì)首頁、末頁、上一頁、下一頁等按鈕),若頁面總數(shù)超過該值則繪制按鈕分隔符 const int BUTTON_COUNT = 7; // 按鈕分隔符 const string BUTTON_SEPARATOR = "......"; //按鈕分隔符左側(cè)按鈕數(shù)目(不計(jì)首頁、末頁、上一頁、下一頁等按鈕) const int LEFT_BUTTON_COUNT = 4; //按鈕分隔符右側(cè)按鈕數(shù)目(不計(jì)首頁、末頁、上一頁、下一頁等按鈕) const int RIGHT_BUTTON_COUNT = 2; string[] urlSegments = Request.Url.Segments; int selectedIndex = 0; int.TryParse(urlSegments[urlSegments.Length - 1], out selectedIndex); int previous = (selectedIndex - 1) <= 0 ? 1 : selectedIndex - 1; int next = (selectedIndex + 1 > pageNumber) ? pageNumber : selectedIndex + 1; var r=Request.Cookies[""]; if (pageNumber > BUTTON_COUNT) { <li><a id="next" href="@redirectUrl/@previous" rel="external nofollow" >上一頁</a></li> for (int i = 1; i <= BUTTON_COUNT; i++) { if ( selectedIndex >= LEFT_BUTTON_COUNT && selectedIndex%LEFT_BUTTON_COUNT==0 && i <= LEFT_BUTTON_COUNT) { <li><a name="pageButton" id="@selectedIndex" href="@redirectUrl/@selectedIndex" rel="external nofollow" >@selectedIndex</a></li> int step = selectedIndex; int tag = 0; for (i = 1; i <= LEFT_BUTTON_COUNT; i++) { tag = i + step; if (tag > pageNumber - RIGHT_BUTTON_COUNT) { if (i <= LEFT_BUTTON_COUNT) { i = LEFT_BUTTON_COUNT + 1; } break; } <li><a name="pageButton" id="@tag" href="@redirectUrl/@tag" rel="external nofollow" rel="external nofollow" >@tag</a></li> } } else if (i <= LEFT_BUTTON_COUNT && selectedIndex<LEFT_BUTTON_COUNT) { <li><a name="pageButton" id="@i" href="@redirectUrl/@i" rel="external nofollow" rel="external nofollow" >@i</a></li> } else if (i < LEFT_BUTTON_COUNT && selectedIndex>LEFT_BUTTON_COUNT) { int step = selectedIndex / LEFT_BUTTON_COUNT; int tag = 0; <li><a name="pageButton" id="@(step*LEFT_BUTTON_COUNT)" href="@redirectUrl/@(step*LEFT_BUTTON_COUNT)" rel="external nofollow" >@(step*LEFT_BUTTON_COUNT)</a></li> for (i = 1; i <= LEFT_BUTTON_COUNT; i++) { tag = i + step * LEFT_BUTTON_COUNT; if (tag > pageNumber - RIGHT_BUTTON_COUNT) { if (i <= LEFT_BUTTON_COUNT) { i = LEFT_BUTTON_COUNT + 1; } break; } <li><a name="pageButton" id="@tag" href="@redirectUrl/@tag" rel="external nofollow" rel="external nofollow" >@tag</a></li> } } //繪制按鈕分隔符右側(cè)按鈕 if (i==BUTTON_COUNT-1) { <li><a name="pageButton" id="@(pageNumber-1)" href="@redirectUrl/@(pageNumber-1)" rel="external nofollow" >@(pageNumber-1)</a></li> } else if(i==BUTTON_COUNT) { <li><a name="pageButton" id="@pageNumber" href="@redirectUrl/@pageNumber" rel="external nofollow" rel="external nofollow" >@pageNumber</a></li> } //繪制按鈕分隔符 else if (i >= BUTTON_COUNT -RIGHT_BUTTON_COUNT) { <li><span name="pageButton">@BUTTON_SEPARATOR</span></li> } } <li><a id="next" href="@redirectUrl/@next" rel="external nofollow" >下一頁</a></li> } else { for (int i = 1; i <= pageNumber; i++) { <li><a name="pageButton" id="@i" href="@redirectUrl/@i" rel="external nofollow" rel="external nofollow" >@i</a></li> } } } <li><a href="@redirectUrl/@pageNumber" rel="external nofollow" rel="external nofollow" >末頁</a></li> </ul> </nav> </div> <script> $(function () { //設(shè)置被選中按鈕的背景色 var selected = $('#@selectedIndex'); if (selected != undefined) { selected.css('background-color', '#E1E1E1'); } </script> }
在前臺(tái)頁面中調(diào)用即可繪制分頁按鈕
@PageHelper.CreatePaginateButton(246, 10, "/usermanager/attentionlist/")
下面是幾張分頁按鈕效果圖:
對(duì)應(yīng)的HTML代碼:
聲明:本網(wǎng)頁內(nèi)容旨在傳播知識(shí),若有侵權(quán)等問題請(qǐng)及時(shí)與本網(wǎng)聯(lián)系,我們將在第一時(shí)間刪除處理。TEL:177 7030 7066 E-MAIL:11247931@qq.com