I have frequently used jquery in my projects. This time I mainly learned to use extjs, but the existing tutorials are basically for 2.0, and the language used in the background is rarely C# under the .net platform. So I plan to use C# in the background for version 3.0 and record my learning process. I hope to discuss it with like-minded friends and make progress together. The official website of extjs is http://www.extjs.com. The highest version currently is 3.0.2, but only version 3.0.0 has no download restrictions. You can click here to download version 3.0. The downloaded compressed package contains the compressed extjs library, libraries used for debugging, readable source code, documents and examples. Before you start, you might as well take a look at the examples in the examples folder to have a perceptual understanding of extjs. If you feel that the effects in the examples make you excited, then start the learning journey of extjs together. First clarify the files we need to reference, including adpter/ext/ext-base-debug.js, ext-all-debug.js and the entire resource folder. Of course, in most cases, we also need ext-lang -zh_CN.js performs Chinese localization. The file is in the src/locale directory. Because it is the learning stage, we use the debug version. In actual projects, the compressed version should be used when publishing to reduce the file size. Next, we will adhere to the consistent tradition in the programming world and start our first Hello world program. Create a new text file, change the file name to Hello.htm, open it with a text editor, and write the following code:
Use ie or ff to open Hello.htm, you can see a pop-up dialog box, which is the same as the js alert dialog box, but much more beautiful. Let’s take a look at the code. In the HTML page, we first reference the relevant library files of extjs. Pay attention to the order of reference. Next, we reference our own js files. Let's take a brief look. Ext.onReady is triggered after the document is loaded. It has a parameter that is a function type, and the function is called when the event is triggered. Here we use an anonymous function. Of course, we can also define the function externally and pass the function name as a parameter. Ext.MessageBox.alert is a dialog box function that pops up a message. The first parameter is the title, and the second parameter is the content of the dialog box. There are also methods under the Ext.Message class to simulate the js prompt dialog box and the comfirm dialog box. Let's modify daben.js to see the effect of the confirm method:
Just looking at the dialog box is not very interesting. In an actual web program, you need to submit data to the server and update the content on the page based on the server's response. Let's take a look at how extjs implements it. . In the example below, we will place an edit box and a button on the page. When the button is clicked, the server will convert the content entered in the edit box into uppercase and display it in a div on the page. Open vs2008, create a new web application ExtjsDemo, and delete the automatically added default.aspx file. Add our hello.htm and daben.js files and the extjs library we want to use. After the addition is completed, as shown in the figure: You can see that a vvswd- is added under the js directory. The file of ext_2.0.2.js can be downloaded from here. This file can implement vs2008’s smart prompt for the extjs library, which is convenient for programming (but I didn’t find one for version 3.0. If If any friend finds it, please send me a copy.) Let’s first look at Ext.Ajax.request, a function in extjs that implements communication with the server. This function accepts a json object as a parameter. This object has several commonly used attributes: url: string type, indicating the request Address params: parameters passed to the server segment when requesting, which can be objects, strings method: request method, string type, "GET" or "POST", note that it must be capitalized Success: Function type, the function that will be executed after the request is successful. The function has one parameter, which is an XMLHttpRequest object containing the server-side response data Failure: Function type, the function that will be executed after the request fails. The function has one The parameter is an XMLHttpRequest object containing server-side response data callback: function type, which will be executed regardless of the result of the request Okay, let’s take a look at how extjs interacts with the server. First make the following changes to our hello.htm page:
Ext.onReady(function() { //Ext.MessageBox.alert("Message","Hello world"); /**//*Ext.MessageBox.confirm("comfirm","Simulate js comfirm dialog box", function(btn){ alert("Clicked the "btn "button"); });* / Ext.get("btn").on("click", function() { var data = Ext.fly("txt").getValue(); if (data == "") { Ext.Msg.alert("Warning", "Please enter a string"); } else { Ext.Ajax.request({ url: " hello.aspx", params: { data: data }, method: "POST", success: function(response) { Ext.fly("div").update(response .responseText); }, failure: function(response) { Ext.Msg.alert("Error", "The request failed, the error code is: " response.status); } }); } }); });
Let’s briefly analyze this file: The first line is to use the smart prompt of vs. Pay attention to writing the path correctly, and it must be added to the first line. Ext.onReady has already been introduced. Ext.fly is the abbreviation of Ext.Element.fly. This method can obtain the Element object based on the id. The Element class is a very important class in Ext. It encapsulates the Dom and adds some Operates for ease of use and is compatible with major browsers. getValue is a method of the Element class to obtain the value of the element. What is frustrating is that there is no corresponding setValue method, so the update method is used later to update the value of the element. It is a good programming habit to verify the client before passing the value to the server. Here we simply verify that the string is not empty, and then use the Ext.Ajax.request method mentioned earlier. Use this method Data is sent to the page hello.aspx in post mode. Here we send it in the form of a json object, or it can also be written in string form. For a successful response, the text of the response is displayed in the div. For a failed response, a pop-up A dialog box and error code are given. The next step is to perform server-side programming. The server can accept the data passed by the client and respond in two ways: using aspx pages and web services. Let's first introduce how to use aspx pages for processing. Add a page Hello.aspx to the project, and add the page processing instructions in the first line of the page to <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Hello.aspx.cs" Inherits="ExtjsDemo .hello" %>Delete all. Press F7 to switch to the code page and start writing background code. We first obtain the data passed from the front desk through Request.Params["data"]. Similarly, before processing the data, we first verify the validity of the data. Here we simply determine whether it is empty or an empty string, and then We will send the processed results to the client using the Response.Write method. The background code is as follows:
After running, enter the string in the edit box. You can see that it is displayed in uppercase in the div below. Through FF's Firebug, we can see the interaction of the data. In addition to using aspx pages to accept and process the data passed by the client, we can also use web services. Add a web service to the project, the code is as follows:
/**//// /// Summary description of HelloService /// [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] [System.ComponentModel.ToolboxItem(false)] // To allow this web service to be called from scripts using ASP.NET AJAX, uncheck the following line annotation. // [System.Web.Script.Services.ScriptService] public class HelloService : System.Web.Services.WebService { Change the incoming string to uppercase #region will be passed Change the entered string to uppercase /**/
namespace ExtjsDemo { /***//// /// Will be passed in Strings that need to be converted to uppercase /// /// Strings that need to be converted to uppercase // / uppercase string [WebMethod] public string ToUpper(string data) { if(!string.IsNullOrEmpty(data)) return data.ToUpper(); throw new Exception("String cannot be empty!"); } #endregion } }
Of course, by default, the web service delivers data in xml format, which we can see through Firebug. XML is very good and powerful, but sometimes we only need smaller JSON. So how do we make the web service deliver JSON format? We only need to set the Content-Type in the request header to application/json and encode the parameters using Ext.util.JSON.encode or use jsonData instead of params.
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