C# 如何读取PDF文件内容

C# 怎么读取PDF文件内容？
怎么能读取到PDF文件里的内容信息,PDF为全英文文本格式 无图片类的东西..
我怎么才能读取到所有信息 然后保存到字符串里面..?

[解决办法]
下载 PDFBox-0.7.3.zip

PDFBox-0.7.3.dll
lucene-demos-2.0.0.dll
lucene-core-2.0.0.dll
bcmail-jdk14-132.dll
bcprov-jdk14-132.dll
FontBox-0.1.0-dev.dll
ICSharpCode.SharpZipLib.dll
IKVM.AWT.WinForms.dll
IKVM.GNU.Classpath.dll
IKVM.Runtime.dll
ikvm-native.dll
放入Bin中

C# code

<%@ Page Language="C#" %><%@ Import Namespace="System" %><%@ Import Namespace="org.pdfbox.pdmodel" %><%@ Import Namespace="org.pdfbox.util" %><script language="C#" runat="server">protected void Page_Load(object sender, System.EventArgs e){    string pdfPath = Server.MapPath("index.pdf");    PDDocument doc = PDDocument.load(pdfPath);    PDFTextStripper stripper = new PDFTextStripper();    string txt = stripper.getText(doc);    Response.Write(txt);}</script>