在网页上查找控制

问题描述：

HTML

<body>
    <form id="form1" runat="server">    
       <asp:Button runat="server" ID="a" OnClick="a_Click" Text="apd"/>    
    </form>
</body>

code

protected  void a_Click(object sender,EventArgs e)
{
    Response.Write(((Button)FindControl("a")).Text);

}

这code正常工作。

不过，这code：

HTML

 <%@ Page Title="" Language="C#" MasterPageFile="~/Student/MasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="Student_Default" %>


<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"> 
</asp:Content> 
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
    <asp:Button runat="server" ID="a" OnClick="a_Click" Text="andj"/>
</asp:Content>

code

protected void a_Click(object sender, EventArgs e)
{
    Response.Write(((Button)FindControl("a")).Text);
}

这code不工作，的FindControl 收益空 - ？这是为什么

This code does not work and FindControl returns Null - why is this?

的的FindControl 方法工作在一个简单的页面罚款，但在母版页，它不工作？

The FindControl method works in a simple page fine, but in a master page, does it not work?

的ID的 A 更改为 ctl00_ContentPlaceHolder1_a - 如何能找到控制

The ID of the a is changed to ctl00_ContentPlaceHolder1_a - how can find control?

答

要找到你所搜索 ContentPlaceHolder1 控制首先在内容页面上的按钮。
然后使用在 ContentPlaceHolder1 控制的FindControl 功能来搜索您的按钮：

To find the button on your content page you have to search for the ContentPlaceHolder1 control first. Then use the FindControl function on the ContentPlaceHolder1 control to search for your button:

 ContentPlaceHolder cph = (ContentPlaceHolder)this.Master.FindControl("ContentPlaceHolder1");
 Response.Write(((Button)cph.FindControl("a")).Text);

在网页上查找控制

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