如何：以编程方式访问 ASP.NET 配置设置
更新：2007 年 11 月
可以从 ASP.NET 应用程序或 .NET 客户端应用程序内部访问运行时配置设置。每个配置节都具有其各自的对象类型，对于 C#，在调用 WebConfigurationManager 类的方法时，需要对这些对象类型进行强制转换。有关与配置节关联的对象类型的更多信息，请参见 ASP.NET 配置设置下参考主题中“元素信息”表中的节处理程序。
此主题中的代码示例使用获取配置数据的非静态方法。这允许您从任何应用程序获取配置信息。如果要从代码驻留的应用程序中获取配置信息，请使用处理速度更快的静态 GetSection 方法。有关更多信息，请参见 ASP.NET 配置 API 概述中的“使用本地和远程配置设置”一节。
示例
下面的代码示例读取针对 MyAppRoot 应用程序配置的 identity 元素的 impersonate 属性值。该值显示在网页上。该代码使用 IdentitySection 对象类型读取 identity 节中的数据。
若要更改配置设置，请使用配置对象的 Save 或 SaveAs 方法。有关更多信息，请参见使用配置类。
<%@ Page Language="VB" %>
<%@ Import Namespace="System.Web.Configuration" %>
<%@ Import Namespace="System.Configuration" %>
<%@ Import Namespace="System.Text" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
' Set the root path of the Web application that contains the
' Web.config file that you want to access.
Dim configPath As String = "/MyAppRoot"
' Get the configuration object to access the related Web.config file.
Dim config As Configuration = WebConfigurationManager.OpenWebConfiguration(configPath)
' Get the object related to the <identity> section.
Dim section As New IdentitySection
section = config.GetSection("system.web/identity")
' Read the <identity> section.
Dim identity As New StringBuilder
identity.Append("Impersonate: ")
identity.Append(section.Impersonate.ToString())
' Display the <identity> information.
ConfigId.Text = identity.ToString()
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Read Configuration Settings</title>
</head>
<body>
<h2>
Read ASP.NET Configuration</h2>
<p>
This page displays the value of the <b>Impersonate</b> attribute of the <b>identity</b>
section of an ASP.NET configuration.
</p>
<h3>
Results</h3>
<p>
<asp:Label ID="ConfigId" BackColor="#dcdcdc" BorderWidth="1" runat="Server" /></p>
</body>
</html>
<%@ Page Language="C#" %>
<%@ Import Namespace="System.Web.Configuration" %>
<%@ Import Namespace="System.Configuration" %>
<%@ Import Namespace="System.Text" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script language="C#" runat="server">
public void Page_Load()
{
try
{
// Set the root path of the Web application that contains the
// Web.config file that you want to access.
string configPath = "/MyAppRoot";
// Get the configuration object to access the related Web.config file.
Configuration config = WebConfigurationManager.OpenWebConfiguration(configPath);
// Get the object related to the <identity> section.
IdentitySection section =
(IdentitySection)config.GetSection("system.web/identity");
// Read the <identity> section.
StringBuilder identity = new StringBuilder();
identity.Append("Impersonate: ");
identity.Append(section.Impersonate.ToString());
// Display the <identity> information.
ConfigId.Text = identity.ToString();
}
catch (Exception e)
{
ConfigId.Text = e.ToString();
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Read Configuration Settings</title>
</head>
<body>
<h2>
Read ASP.NET Configuration</h2>
<p>
This page displays the value of the <b>Impersonate</b> attribute of the <b>identity</b>
section of an ASP.NET configuration.
</p>
<h3>
Results</h3>
<p>
<asp:Label ID="ConfigId" BackColor="#dcdcdc" BorderWidth="1" runat="Server" /></p>
</body>
</html>