ExtJS 如何动态加载JavaScript创建窗体

Posted 周四, 07/14/2016 - 09:17 by admin

JavaScript不需要编译即可运行，这让JavaScript构建的应用程序可以变得很灵活。我们可以根据需要动态从服务器加载JavaScript脚本来创建和控制UI来与用户交互。下面结合Ext JS来说明如何从服务器上动态加载JS脚本来动态创建窗体。

1 项目结构：

项目结构如下：其中GetJSUI一般处理程序用来从数据库表中抓取UI配置，并返回到客户端；Contents文件夹下用HTML文件和JS库等。

2 数据库表结构

可以用下面的SQL在MSSQL中创建表，其中JavaScriptContent字段存储具体的JS脚本。

CREATE TABLE [dbo].[Ext_Dynamic_Form](
    [ID] [nvarchar](50) NOT NULL,
    [UniName] [nvarchar](50) NULL,
    [JavaScriptContent] [nvarchar](4000) NULL,
    [Memo] [nvarchar](200) NULL,
 CONSTRAINT [PK_Ext_Dynamic_Form] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)
) ON [PRIMARY]

3 创建好后，可以初始化数据：

4 GetJSUI 编程

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using CMCloudDBHelper;
namespace extjs6.Services
{
    /// <summary>
    /// author:jackwangcumt
    /// </summary>
    public class GetJSUI : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            string js = "";
            context.Response.ContentType = "text/plain";
            //context.Response.ContentType = "text/javascript";
            CMCDataAccess da = new CMCDataAccess();
            string SQLForJS = "select * FROM Ext_Dynamic_Form where ID='006'";
             System.Data.DataTable dt=  da.GetDataTable(SQLForJS);
            if(dt!=null)
            {
                if(dt.Rows.Count==1)
                {
                     js = dt.Rows[0]["JavaScriptContent"].ToString();
                }

            }
          
            //utf-8
            context.Response.ContentEncoding = System.Text.Encoding.UTF8;
            context.Response.Write(js);

        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

5 主界面html

<html>
<head>
    <title>Dynamically generate forms from server javascript</title>
    <!-- Library Files -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge" charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
    <script type="text/javascript" src="ext6/ext-all-debug.js"></script>
    <link rel="stylesheet" type="text/css" href="ext6/classic/theme-triton/resources/theme-triton-all-debug.css">
    <script type="text/javascript" src="ext6/classic/theme-triton/theme-triton-debug.js"></script>
    <script type="text/javascript">
    //load *.js file from server
    function loadScript(url, callback) {

        var script = document.createElement("script")
        script.type = "text/javascript";

        if (script.readyState) { //IE
            script.onreadystatechange = function() {
                if (script.readyState == "loaded" ||
                    script.readyState == "complete") {
                    script.onreadystatechange = null;
                    callback();
                }
            };
        } else { //Others
            script.onload = function() {
                callback();
            };
        }
        script.src = url;
        document.getElementsByTagName("head")[0].appendChild(script);
    }
    //load js text from server
    function loadScriptSrc(js, callback) {

        var script = document.createElement("script")
        script.type = "text/javascript";
        //script.async = true;
        if (script.readyState) { //IE
            script.onreadystatechange = function() {
                if (script.readyState == "loaded" ||
                    script.readyState == "complete") {
                    script.onreadystatechange = null;
                    callback();
                }
            };
        } else { //Others
            script.onload = function() {
                callback();
            };
        }
   
        script.text = js;
        console.log(script);
        document.getElementsByTagName("head")[0].appendChild(script);
        //不能少
        callback();
    }
    //Ext JS 6
    Ext.onReady(function() {
        //https://www.sencha.com/forum/showthread.php?268193-How-to-load-content-dynamically-for-tabpanel
        var pmain = Ext.widget('panel', {
            renderTo: document.body,
            height: 800,
            width: 800,
            layout: 'border',
            items: [{
                title: 'West',
                region: 'west',
                width: 200,
                collapsible: true
            }, {
                xtype: 'tabpanel',
                region: 'center',
                items: [{
                    title: 'First Tab',
                    itemId: 'tab01',
                }, {
                    title: 'Second Tab',
                    layout: 'fit',
                    loader: {
                        url: 'Form.json',
                        autoLoad: true,
                        renderer: 'component'
                    }
                }]
            }]
        });
        //ajax config
        var reqConfig = {
                 url: '../Services/GetJSUI.ashx',
                 method: 'get',
                 callback: function (options, success, response) {
                  
                     // var msg = ['success:', success, '\n', 'data:', response.responseText];
                      //  alert(msg.join(''));
                        loadScriptSrc(response.responseText, function() {
                        Ext.Msg.alert("loaded js","从服务器加载JS完成");

                        var gp = Ext.create("gpView");
        
                        Ext.ComponentQuery.query('#tab01')[0].add(gp);


                    });
                 }
             };
        Ext.Ajax.request(reqConfig);

        //loadScript("dynamicLoadJS2.js", function() {
        //    Ext.Msg.alert("loaded");

        //    var gp = Ext.create("gpView");
        //    //console.log(gp);
        //    //gp.body.renderTo(pmain);
        //    // Ext.ComponentQuery.query('#tab01')[0].add({
        //    //     html: 'Oh, Hello.'
        //    // });
        //    Ext.ComponentQuery.query('#tab01')[0].add(gp);


        //});


    });
    </script>
</head>

<body>
</body>

</html>