The footer CSS does not work when the page loads dynamic content at button click

问题

.html

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

<!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></title>
    <link href="dark.css" rel="stylesheet" type="text/css" id="stylesheet" />
</head>
<body>
    <form id="form1" runat="server">
    <div>

    </div>
    <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />
    <asp:Label ID="CaptionLabel" runat="server"></asp:Label>
    <asp:TextBox ID="NumberTextbox" runat="server">(empty)</asp:TextBox>
    <asp:Button ID="SquareButton" runat="server" Text="Square" style="background-color:Blue; color:White;" />
    <asp:Label ID="ResultLabel" runat="server" Text="(empty)" CssClass="reverse"></asp:Label>
    <p>
        <asp:Label ID="Label1" runat="server" CssClass="footer1" 
            Text="Label Label Label Label LabelLabelLabel Label Label Label Label Label Label Label"></asp:Label>
    </p>
    <asp:RadioButton ID="radioDark" runat="server" AutoPostBack="True" 
        Checked="True" GroupName="grpSelectStylesheet" 
        oncheckedchanged="SwitchStylesheets" Text="Dark" />
    <br />
    <asp:RadioButton ID="radioLight" runat="server" AutoPostBack="True" 
        GroupName="grpSelectStylesheet" oncheckedchanged="SwitchStylesheets" 
        Text="Light" />
    <asp:GridView ID="GridView1" runat="server">
    </asp:GridView>
    </form>
    </body>
</html>

.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {


    }
    protected void SwitchStylesheets(object sender, EventArgs e)
    {
        if (radioDark.Checked)
            stylesheet.Href = "dark.css";
        if (radioLight.Checked)
            stylesheet.Href = "light.css";

    }
    protected void Button1_Click(object sender, EventArgs e)
    {

        int count=DateTime.Now.Second;
        for (int i = 0; i < count; i++)
        {//for
            Label q = new Label();
            q.ID = DateTime.Now.Second.ToString();

            q.Text = DateTime.Now.Second.ToString();
            string spacee = "<br />";
            Label space = new Label();
            space.Text = spacee;
            form1.Controls.Add(q);
            form1.Controls.Add(space);
        }//for
    }
}

When the button is clicked, it works as it should but the footer does not register the expansion of the page.

回答1:

Your code is completely wrong. you cannot change the stylesheet like this for a control even if the autopostback is set to true.
UPDATE: Here's how you should do it:

1- Remove the .css reference from your page.
2- Add this method to your page:

  private void UpdateStylesheet(string filepath)  
  {  
     HtmlLink newStyleSheet = new HtmlLink();  
     newStyleSheet.Href = filepath;       
     newStyleSheet.Attributes.Add("type", "text/css");  
     newStyleSheet.Attributes.Add("rel", "stylesheet");  
     Page.Header.Controls.Add(newStyleSheet);  
 }

3- Add this line to your page_load event:

UpdateStylesheet("dark.css");

4- Handle the SwitchStylesheets like this:

 if (radioDark.Checked)  
        UpdateStylesheet("dark.css");   
    if (radioLight.Checked)  
        UpdateStylesheet("light.css");

来源：https://stackoverflow.com/questions/4059485/the-footer-css-does-not-work-when-the-page-loads-dynamic-content-at-button-click

标签

dynamic

css