CustomJSProperties珍藏版。目的是减少客户端的代码数量，但是又能将服务器数据传输给客户端。关键是：数据是实时更新的！！！！

[这是帮助文档的说明]

CustomJSProperties Event
The CustomJSProperties event fires each time a control callback or page postback is sent to the server side. The
event enables you to declare temporary client properties using the event parameter's
CustomJSPropertiesEventArgs.Properties property, which is a collection of property names and their values. Once
declared, a property can be accessed on the client.
Note
Typically, using the JSProperties property will be more convenient and efficient than handling the
CustomJSProperties event, which is primarily declared for backward compatibility

Last month, I was creating a sample with the ASPxGridView when I needed to access the PageIndex property from the client side. The PageIndex property holds the current page index number. I needed to use the PageIndex for a client side function. Unfortunately, this property was only available on the server side. I used my keen insight to come up with the perfect suggestion to enhance the product: Just open up a bunch of server properties on the client side! Luckily, someone smarter than me (Andrew the ASPxGridView Architect) saw what a horrible idea that really was and came up with this enhancement that works better and does more...

A new method allows you to expose almost any server side property to the client side.

Using an ingenious technique which creates temporary client properties so that the client side is not weighed down with extra HTML or JavaScript if it's not needed.

【有一种方法可以向客户端提供服务器的任何属性，目的是使得客户端比较小，仅仅下载需要的代码，目的是提升速度】

The CustomJSProperties event enables you to declare temporary client properties. Once declared, these properties can be accessed from the client side. To add a new property, use the event parameter's http://documentation.devexpress.com/#AspNet/clsDevExpressWebASPxGridViewASPxGridViewClientJSPropertiesEventArgstopic property (this represents a collection of property names and their values).

For example, to expose the PageIndex property, first override the CustomJSProperties event and add your custom property to expose to the client side:

protected void ASPxGridView1_CustomJSProperties(object sender, 
   DevExpress.Web.ASPxGridView.ASPxGridViewClientJSPropertiesEventArgs e) 
{
   e.Properties["cpPageIndex"] = ASPxGridView1.PageIndex;
}

That's it, your done. Now you're free to call this property from the client side:

<input id="Button2" type="button" value="Active Page" 
   onclick="alert(grid.cpPageIndex)" />

To avoid rewriting the ASPxGridView’s base properties, prefix the client side property name with "cp" for custom property (e.g. cpPageIndex).

Here is a sample project that shows how it’s done: [CustomJSProperties.zip]

Thanks.

Mehul Harry (DevExpress)Web Program Manager

Email: mharry@devexpress.com

Twitter: @Mehulharry

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="CustomJSProperties.aspx.cs" Inherits="CustomJSProperties" %>

<%@ Register assembly="DevExpress.Web.v17.2, Version=17.2.7.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" namespace="DevExpress.Web" tagprefix="dx" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
        
        <asp:AccessDataSource ID="AccessDataSource1" runat="server" 
            DataFile="~/App_Data/nwind.mdb" 
            SelectCommand="SELECT [CustomerID], [CompanyName], [ContactName], [City], [Country] FROM [Customers]">
        </asp:AccessDataSource>
    
        <dx:ASPxGridView ID="ASPxGridView2" runat="server" AutoGenerateColumns="False" 
            DataSourceID="AccessDataSource1" KeyFieldName="CustomerID" 
            ClientInstanceName="grid" 
            oncustomjsproperties="ASPxGridView2_CustomJSProperties">
            <Columns>
                <dx:GridViewDataTextColumn FieldName="CustomerID" ReadOnly="True" 
                    VisibleIndex="0">
                </dx:GridViewDataTextColumn>
                <dx:GridViewDataTextColumn FieldName="CompanyName" VisibleIndex="1">
                </dx:GridViewDataTextColumn>
                <dx:GridViewDataTextColumn FieldName="ContactName" VisibleIndex="2">
                </dx:GridViewDataTextColumn>
                <dx:GridViewDataTextColumn FieldName="City" VisibleIndex="3">
                </dx:GridViewDataTextColumn>
                <dx:GridViewDataTextColumn FieldName="Country" VisibleIndex="4">
                </dx:GridViewDataTextColumn>
            </Columns>
        </dx:ASPxGridView>
        <dx:ASPxButton ID="ASPxButton2" runat="server" EnableTheming="True" 
            Text="查询当前页码" Theme="Material">
            <clientsideevents click="function(s, e) {
    alert(grid.cpPageIndex);
}" />
        </dx:ASPxButton>
        <br />
    
    </div>
    </form>
</body>
</html>

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

public partial class CustomJSProperties : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    
    //实时提供服务器变量
    protected void ASPxGridView2_CustomJSProperties(object sender, DevExpress.Web.ASPxGridViewClientJSPropertiesEventArgs e)
    {
        e.Properties["cpPageIndex"] = ASPxGridView2.PageIndex + 1;
    }
}

posted on 2019-01-17 19:11 qqhfeng16 阅读(533) 评论(0) 编辑收藏举报