这是我的所有代码:
的Site.Master
<%@ Master Language="C#" AutoEventWireup="true"
CodeBehind="Site.master.cs" Inherits="WebApplication1.SiteMaster" %>
<!DOCTYPE html>
<html>
<head runat="server">
<title></title>
<link href="~/Styles/Site.css" rel="stylesheet" type="text/css" />
<asp:ContentPlaceHolder ID="HeadContent" runat="server">
</asp:ContentPlaceHolder>
</head>
<body>
<form runat="server">
<div class="main">
<asp:ContentPlaceHolder ID="MainContent" runat="server"/>
</div>
</form>
</body>
</html>
Site.Master.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebApplication1
{
public partial class SiteMaster : System.Web.UI.MasterPage
{
protected void Page_Load(object sender, EventArgs e)
{
}
}
}
Default.aspx的
<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master"
AutoEventWireup="true" CodeBehind="Default.aspx.cs"
Inherits="WebApplication1._Default" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
<asp:ListBox ID="ListBox1" runat="server"></asp:ListBox>
</asp:Content>
Default.aspx.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebApplication1
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
ListBox ListBox1 = new ListBox();
ListBox1.FindControl("ListBox1");
ListBox1.Items.Add(new ListItem("Hello"));
}
}
}
问题:为什么我的ListBox没有填充?
运行代码时,我得到一个页面,其中包含一个完全空的小框。
我已经尝试了以下内容,我会告诉你结果 -
ListBox ListBox1 = new ListBox();
ListBox1.FindControl("ListBox1");
结果:当前上下文中不存在名称“ListBox1”
结果:对象引用未设置为对象的实例。
要解决该错误,请添加第ListBox ListBox1 = new ListBox();
行,但仍无法显示。
有什么想法吗?感谢。
答案 0 :(得分:2)
你应该只需要......
protected void Page_Load(object sender, EventArgs e)
{
ListBox1.Items.Add(new ListItem("Hello", "H"));
}
另见link
编辑:相同的代码适用于我。
答案 1 :(得分:0)
直接回答您为什么ListBox1
没有填充的问题:
protected void Page_Load(object sender, EventArgs e)
{
ListBox ListBox1 = new ListBox(); //You are creating a new local ListBox named ListBox1.
ListBox1.FindControl("ListBox1"); //You are trying to find the Control named ListBox1 that is held within the Control ListBox1 (and not doing anything with the result of the search)
ListBox1.Items.Add(new ListItem("Hello")); //You are adding a new ListItem to the local ListBox1.
}
正如christiandev所说,你应该能够做到这一点:
protected void Page_Load(object sender, EventArgs e)
{
ListBox1.Items.Add(new ListItem("Hello"));
}
我不知道为什么你似乎无法访问aspx页面上的ListBox1。