Use jQuery and AJAX technology to regularly update a certain column of GridView data

Home

Web Front-end

JS Tutorial

Use jQuery and AJAX technology to regularly update a certain column of GridView data_jquery

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

May 16, 2016 pm 03:27 PM

ajaxjquery

I saw a problem: regularly update the status text in a column of the GridView. An idea immediately came to mind: GridView will eventually generate a table, so we update the columns of the table through Ajax on the page to achieve the effect of ajax updating GridView.

Detailed implementation:

Prepare an xml file to store the data to be updated, start a timer in the page, and call a function every 5 seconds. The function uses $.ajax to obtain the data in the xml, parse the xml, and traverse the table. Rows that match the data to be updated are updated.

getuserlist.xml

Define the root node of a UserList. Each UserItem below corresponds to a piece of data. UID can be understood as the primary key, and UStatus is the latest status.

<&#63;xml version="1.0" encoding="utf-8" &#63;>
<UserList>
<UserItem><UID>1</UID><UStatus>关闭</UStatus></UserItem>
<UserItem><UID>2</UID><UStatus>关闭</UStatus></UserItem>
<UserItem><UID>3</UID><UStatus>开放</UStatus></UserItem>
</UserList>

test.html

The specific logic is written here.

<html>
 <head>
 <title>Ajax Update Table Column</title>
 <script src="jquery-1.3.1.min.js" type="text/javascript"></script>
 <script type="text/javascript">
  window.onload=function(){
  //每隔5秒检查一下数据
  window.setInterval(checkStatus,5000);
  };
 
  //检查数据
  function checkStatus(){
  //ajax请求数据
  $.ajax({
   //换成你的文件，构造xml格式的数据就行了
  url: 'getuserlist.xml',
  //请求类型
  type: 'GET',
  //数据格式
  dataType: 'xml',
  //超时时间：1秒
  timeout: 2000,
  //加载数据发生错误
  error:function (XMLHttpRequest, textStatus, errorThrown) {
   alert("XMLHttpRequest="+XMLHttpRequest.responseText+"\ntextStatus="+textStatus+"\nerrorThrown="+errorThrown);
  },
  //成功加载数据
  success: function(xml){

//遍历表格的行，需要给表格定义一个ID
   $("#userListTable tr").each(function(){

//获取行的第一列，这里边保存了XML中对应的UID信息
    var trID=$(this).find("td").eq(0).text();

//数据的新状态
    var trStatus="";

//遍历xml中的UserItem
    $(xml).find("UserList > UserItem").each(function(){

//获取UID和UStatus的值
   var uid = $(this).find("UID").text();
   var ustatus = $(this).find("UStatus").text();

//比对当前行的ID和UID，如果相等，给数据的新状态赋值
    if(trID==uid){
     trStatus=ustatus;
    }
    });

//如果数据的新状态不为空，则更新单元格中现实的文本
    if(trStatus!=""){
   $(this).find("td").eq(2).text(trStatus);
    }
   });
  }
   });
  }
 </script>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 </head>
 <body>

<!--

这个表格有三列

ID：数据的ID，相当于主键，用于从xml中查询新数据

Name：只是显示

Status：要更新的列

-->
 <table border="1" id="userListTable">
  <tr><th>ID</th><th>Name</th><th>Status</th></tr>
  <tr><td>1</td><td>张三</td><td>开放</td></tr>
  <tr><td>2</td><td>李四</td><td>开放</td></tr>
  <tr><td>3</td><td>王五</td><td>开放</td></tr>
 </table>
 </body>
</html>

Finally, place the required files under a browsable site and open test.html.
Wait for 5 seconds and you will see the effect.

Due to a problem with IE, opening it directly in a folder will cause the problem of being unable to parse the xml file (parsererror), so it is recommended to put it under a site that can be run, or open it with another browser.

PS: GridView is the successor control of DataGrid. In framework 2, although DataGrid still exists, GridView has come to the forefront of history, and the trend of replacing DataGrid is unstoppable. GridView and DataGrid have similar functions. They both display data from the data source on the web page, and display a row of data in the data source, that is, a record, as a row in the output table on the web page.
Compared with DataGrid, GridView has the following advantages and is richer in functions. Because it provides a smart tag panel (that is, show smart tag), it is easier to use and more convenient. Commonly used operations such as sorting, paging, updating, and deletion can be implemented with zero code! With the PagerTemplate attribute, the user navigation page can be customized, which means that the control of paging is more arbitrary. GridView and DataGrid also have many differences in event models. The DataGrid control triggers a single event, while the GridView control triggers two events, one before the operation and one after the operation. The event before the operation is multiple. ***ing event, the event after the operation is multiple ***ed events, such as Sorting event and sorted event, RowDeleting and RowDeleted event.
The way to refresh the interface of Listview and Gridview is to call adapter.notifyDataSetChanged() to refresh the interface.
However, this method has its drawbacks. It refreshes all the data in the interface, regardless of whether the data has changed or not.

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Python vs. JavaScript: Community, Libraries, and ResourcesApr 15, 2025 am 12:16 AM

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

From C/C to JavaScript: How It All WorksApr 14, 2025 am 12:05 AM

The shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.

JavaScript Engines: Comparing ImplementationsApr 13, 2025 am 12:05 AM

Different JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.

Beyond the Browser: JavaScript in the Real WorldApr 12, 2025 am 12:06 AM

JavaScript's applications in the real world include server-side programming, mobile application development and Internet of Things control: 1. Server-side programming is realized through Node.js, suitable for high concurrent request processing. 2. Mobile application development is carried out through ReactNative and supports cross-platform deployment. 3. Used for IoT device control through Johnny-Five library, suitable for hardware interaction.

Building a Multi-Tenant SaaS Application with Next.js (Backend Integration)Apr 11, 2025 am 08:23 AM

I built a functional multi-tenant SaaS application (an EdTech app) with your everyday tech tool and you can do the same. First, what’s a multi-tenant SaaS application? Multi-tenant SaaS applications let you serve multiple customers from a sing

How to Build a Multi-Tenant SaaS Application with Next.js (Frontend Integration)Apr 11, 2025 am 08:22 AM

This article demonstrates frontend integration with a backend secured by Permit, building a functional EdTech SaaS application using Next.js. The frontend fetches user permissions to control UI visibility and ensures API requests adhere to role-base

JavaScript: Exploring the Versatility of a Web LanguageApr 11, 2025 am 12:01 AM

JavaScript is the core language of modern web development and is widely used for its diversity and flexibility. 1) Front-end development: build dynamic web pages and single-page applications through DOM operations and modern frameworks (such as React, Vue.js, Angular). 2) Server-side development: Node.js uses a non-blocking I/O model to handle high concurrency and real-time applications. 3) Mobile and desktop application development: cross-platform development is realized through ReactNative and Electron to improve development efficiency.

The Evolution of JavaScript: Current Trends and Future ProspectsApr 10, 2025 am 09:33 AM

The latest trends in JavaScript include the rise of TypeScript, the popularity of modern frameworks and libraries, and the application of WebAssembly. Future prospects cover more powerful type systems, the development of server-side JavaScript, the expansion of artificial intelligence and machine learning, and the potential of IoT and edge computing.

See all articles