Building a Web Application->Sharing Code Between Pages

Although you can place code inside //在...里面each page within your site//在站点里 (using the inline or code-behind separation models described in the previous section//前一部分), there are times when you will want to share code //共享代码across several pages //通过几个页面in your site. It would be inefficient //低效率的and difficult to maintain//维护 this code by copying it to every page //复制到每个页面中that needs it. Fortunately//幸运地, ASP.NET provides several convenient//方便的 ways to make code accessible//可得到的,易接近的,可进入的 to all pages//所有的页面 in an application.

The Code Directory //代码目录New in 2.0

Just as pages can be compiled dynamically //动态编译at runtime, so can arbitrary //任意的,恣意的,专制的code files (for example .cs or .vb files). ASP.NET 2.0 introduces the App_Code directory, which can contain standalone//独立的,单独的 files that contain code to be shared across several pages//几个页面共享 in your application. Unlike ASP.NET 1.x, which required these files to be precompiled //预编译to the Bin directory//二进制目录, any code files in the App_Code directory will be dynamically compiled //动态编译at runtime and made available to//成为可用 the application. It is possible to place files of more than one language under the App_Code directory, provided they are partitioned//分割开 in subdirectories//子目录 (registered with a particular language in Web.config). The example below demonstrates using the App_Code directory to contain a single class file //类文件called //调用from the page.

C# App_Code Folder Example

文件夹层次显示如下:

其中:CodeFolder_cs.aspx

<%@ page language="C#" %>

void Button1_Click(object sender, EventArgs e)

{

CustomClass c = new CustomClass();

Label1.Text = c.GetMessage(TextBox1.Text);

}

</script>

<html>

<head>

<title>ASP.NET Inline Pages</title>

</head>

<body>

<h1>Welcome to ASP.NET 2.0!</h1>

<b>Enter Your Name:</b>

<asp:TextBox ID="TextBox1" Runat="server"/>

<asp:Button ID="Button1" Text="Click Me" OnClick="Button1_Click" Runat="server"/>

<br />

<asp:Label ID="Label1" Text="Hello" Runat="server" />

</form>

</body>

</html>

CustomClass.cs

//-----------------------------------------------------------------------

// This file is part of the Microsoft .NET SDK Code Samples.

//This source code is intended only as a supplement to Microsoft

//Development Tools and/or on-line documentation. See these other

//materials for detailed information regarding Microsoft code samples.

//THIS CODE AND INFORMATION ARE PROVIDED AS IS WITHOUT WARRANTY OF ANY

//KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE

//IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A

//PARTICULAR PURPOSE.

//-----------------------------------------------------------------------

using System;

public class CustomClass

{

public String GetMessage(String input) {

return "Hello " + input;

}

By default,//默认情况下. the App_Code directory can only contain files of the same language. However, you may partition//分割开 the App_Code directory into subdirectories//子目录 (each containing files of the same language) in order to contain multiple languages under the App_Code directory. To do this, you need to register each subdirectory //子目录in the Web.config file for the application.

<configuration>
<system.web>
<compilation>
<codeSubDirectories>
<add directoryName="Subdirectory"/>
</codeSubDirectories>
</compilation>
</system.web>
</configuration>

The following example demonstrates an App_Code directory partitioned //分割开to contain files in both the VB and C# languages.

C# Partitioned App_Code Folder Example

文件夹层次显示如下:

其中:CodeFolder2_cs.aspx

<%@ page language="C#" %>

void Button1_Click(object sender, EventArgs e)

{

CustomClass c = new CustomClass();

Label1.Text = c.GetMessage(TextBox1.Text);

CustomClass2 c2 = new CustomClass2();

Label2.Text = c2.GetMessage(TextBox1.Text);

}

</script>

<html>

<head>

<title>ASP.NET Inline Pages</title>

</head>

<body>

<h1>Welcome to ASP.NET 2.0!</h1>

<b>Enter Your Name:</b>

<asp:TextBox ID="TextBox1" Runat="server"/>

<asp:Button ID="Button1" Text="Click Me" OnClick="Button1_Click" Runat="server"/>

<br />

<asp:Label ID="Label1" Runat="server" />

<br />

<asp:Label ID="Label2" Runat="server" />

</form>

</body>

</html>

Web.config

<system.web>

</codeSubDirectories>

</compilation>

</system.web>

</configuration>