6

.NET 2.0/VS2005

我正在尝试使用XslCompiledTransform该类来执行 XSL 转换。<xsl:include>我有两个 XSL 文件，其中第一个以语句的形式包含对另一个的引用：

主要.xsl：

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:include href="Included.xsl" />
  ...
  ...
</xsl:stylesheet>

现在，如果我可以将“Main.xsl”文件本身作为 URI 加载，我的转换代码将非常简单：

// This is a function that works. For demo only.
private string Transform(string xslFileURI)
{
  XslCompiledTransform xslt = new XslCompiledTransform();

  // This load works just fine, if I provide the path to "Main.xsl".
  // The xsl:include is automatically resolved.
  xslTransform.Load(xslFileURI);

  StringWriter sw = new StringWriter();
  xslt.Transform(Server.MapPath("~/XML/input.xml"), null, sw);
  return sw.ToString();
}

问题是我将 Main.xsl 文件的内容作为字符串接收，需要将该字符串加载为XmlReader/IXpathNavigable. 这是此时的必要限制。当我尝试使用 做同样的事情时XmlReader/XpathDocument，它失败了，因为代码在文件夹中查找“Included.xsl” C:\Program Files\Microsoft Visual Studio 8\Common7\IDE\！显然，XmlResolver它无法解析相对 URL，因为它只接收一个字符串作为输入 XSL。

我在这个方向上的努力如下：

// This doesn't work! Halp!
private string Transform(string xslContents)
{
  XslCompiledTransform xslt = new XslCompiledTransform();
  XmlUrlResolver resolver = new XmlUrlResolver();
  resolver.Credentials = CredentialCache.DefaultCredentials;

  //METHOD 1: This method does not work.
  XmlReaderSettings settings = new XmlReaderSettings();
  settings.XmlResolver = resolver;
  XmlReader xR = XmlReader.Create(new StringReader(xslContents), settings);
  xslt.Load(xR);    // fails

  // METHOD 2: Does not work either.
  XPathDocument xpDoc = new XPathDocument(new StringReader(xslContents));
  xslt.Load(xpDoc, new XsltSettings(true, true), resolver);  //fails.

  StringWriter sw = new StringWriter();
  xslt.Transform(Server.MapPath("~/XML/input.xml"), null, sw);
  return sw.ToString();
}

我曾尝试使用ResolveUriXmlUrlResolver 的方法来获取Stream要包含的 XSL 文件的引用，但对如何使用此 Stream 感到困惑。XslCompiledTransformIOW，除了 Main.xsl XmlReader ，我如何告诉对象使用这个流：

Uri mainURI = new Uri(Request.PhysicalApplicationPath + "Main.xsl");
Uri uri = resolver.ResolveUri(mainURI, "Included.xsl");

// I can verify that the Included.xsl file loads in the Stream below.
Stream s = resolver.GetEntity(uri, null, typeof(Stream)) as Stream;

// How do I use this Stream in the function above??


任何帮助是极大的赞赏。对不起，很长的帖子！

供您参考，Exception StackTrace 如下所示：

[FileNotFoundException: Could not find file 'C:\Program Files\Microsoft Visual Studio 8\Common7\IDE\Included.xsl'.]
   System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath) +328
   System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy) +1038
   System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize) +113
   System.Xml.XmlDownloadManager.GetStream(Uri uri, ICredentials credentials) +78
   System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn) +51
   System.Xml.Xsl.Xslt.XsltLoader.CreateReader(Uri uri, XmlResolver xmlResolver) +22
   System.Xml.Xsl.Xslt.XsltLoader.LoadStylesheet(Uri uri, Boolean include) +33
   System.Xml.Xsl.Xslt.XsltLoader.LoadInclude() +349
   System.Xml.Xsl.Xslt.XsltLoader.LoadRealStylesheet() +704
   System.Xml.Xsl.Xslt.XsltLoader.LoadDocument() +293
   System.Xml.Xsl.Xslt.XsltLoader.LoadStylesheet(XmlReader reader, Boolean include) +173
4

4 回答 4

6

使用自定义 XmlUrlResolver

class MyXmlUrlResolver : XmlUrlResolver
    {
        public override Uri ResolveUri(Uri baseUri, string relativeUri)
        {
            if (baseUri != null)
                return base.ResolveUri(baseUri, relativeUri);
            else
                return base.ResolveUri(new Uri("http://mypath/"), relativeUri);
        }
    }

并在 XslCompiledTransform 的加载函数中使用它，

resolver=new MyXmlUrlResolver();
xslt.Load(xR,null,resolver);
于 2009-06-15T12:28:46.160 回答
4

As Gee's answer mentions, you want to use a custom XmlResolver (of which XmlUrlResolver is already derived), but if you also override the method GetEntity you can resolve references in the primary XSLT document in fun and interesting ways. A deliberately simple example of how you could resolve the reference to Included.xsl:

public class CustomXmlResolver : XmlResolver
{
    public CustomXmlResolver() { }

    public override ICredentials Credentials
    {
        set { }
    }

    public override object GetEntity(Uri absoluteUri, string role, Type ofObjectToReturn)
    {
        MemoryStream entityStream = null;

        switch (absoluteUri.Scheme)
        {
            case "custom-scheme":

                string absoluteUriOriginalString = absoluteUri.OriginalString;
                string ctgXsltEntityName = absoluteUriOriginalString.Substring(absoluteUriOriginalString.IndexOf(":") + 1);
                string entityXslt = "";

                // TODO: Replace the following with your own code to load data for referenced entities.
                switch (ctgXsltEntityName)
                {
                    case "Included.xsl":
                        entityXslt = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<xsl:stylesheet version=\"1.0\" xmlns:xsl=\"http://www.w3.org/1999/XSL/Transform\">\n  <xsl:template name=\"Included\">\n\n  </xsl:template>\n</xsl:stylesheet>";
                        break;
                }

                UTF8Encoding utf8Encoding = new UTF8Encoding();
                byte[] entityBytes = utf8Encoding.GetBytes(entityXslt);
                entityStream = new MemoryStream(entityBytes);

                break;
        }

        return entityStream;
    }

    public override Uri ResolveUri(Uri baseUri, string relativeUri)
    {
        // You might want to resolve all reference URIs using a custom scheme.
        if (baseUri != null)
            return base.ResolveUri(baseUri, relativeUri);
        else
            return new Uri("custom-scheme:" + relativeUri);
    }
}

When you load the Main.xsl document you'd change the relevant code to the following:

xslt.Load(xpDoc, new XsltSettings(true, true), new CustomXmlResolver());

The above example was based on info I picked-up in the MSDN article Resolving the Unknown: Building Custom XmlResolvers in the .NET Framework.

于 2012-07-31T14:02:27.930 回答
2

我可能遗漏了明显的内容，但是您是否有理由不将 Included.xsl 的 URI 更改为真正的 URL？如果您有权访问或使用字符串操作，这可以在 XSL 文档中完成吗？

于 2009-06-15T11:38:28.807 回答
0

我已经成功使用内存中的 all 进行转换：

具有包含以下内容的 xslt 包括：

导入 href="Common.xslt" 和导入 href="Xhtml.xslt"

    private string Transform(string styleSheet, string xmlToParse)
            {
                XslCompiledTransform xslt = new XslCompiledTransform();

                MemoryResourceResolver resolver = new MemoryResourceResolver();            


                XmlTextReader xR = new XmlTextReader(new StringReader(styleSheet));           

                xslt.Load(xR, null, resolver);

                StringWriter sw = new StringWriter();                


                using (var inputReader = new StringReader(xmlToParse))
                {
                    var input = new XmlTextReader(inputReader);
                    xslt.Transform(input,
                                        null,
                                        sw);
                }

                return sw.ToString();

            }     

    public class MemoryResourceResolver : XmlResolver
        {

            public override object GetEntity(Uri absoluteUri,
              string role, Type ofObjectToReturn)
            {
                if (absoluteUri.ToString().Contains("Common"))
                {
                    return new MemoryStream(Encoding.UTF8.GetBytes("Xml with with common data"));
                }

                if (absoluteUri.ToString().Contains("Xhtml"))
                {
                    return new MemoryStream(Encoding.UTF8.GetBytes("Xml with with xhtml data"));
                }         

                return "";
            }
        }

请注意，绝对所有内容都是字符串：styleSheet、xmlToParse 以及“Common”和“Xhtml”导入的内容

于 2015-10-19T16:11:56.990 回答