有没有办法调试由自定义xmlurlresolver从数据库加载的xslt文档，或者有人知道下面的错误消息是关于什么的？
我有一个导入公共xslt文档的xslt样式表：

<xsl:import href="db://common.hist.org"/>

_xslHtmlOutput = new XslCompiledTransform(XSLT_DEBUG);

public class XmlDBResolver : XmlUrlResolver
{
    private IDictionary<string,string> GetUriComponents(String uri)
    {
        bool useXmlPre = false;
        uri = uri.Replace("db://", "");
        useXmlPre = uri.StartsWith("xml/");
        uri = uri.Replace("xml/", "");
        IDictionary<string, string> dict = new Dictionary<string, string>();
        string app = null, area = null, subArea = null;

        if (!String.IsNullOrWhiteSpace(uri))
        {
            string[] components = uri.Split('.');

            if (components == null)
                throw new Exception("Invalid Xslt URI");

            switch (components.Count())
            {
                case 3:
                    app = components[0];
                    break;
                case 4:
                    area = components[0];
                    app = components[1];
                    break;
                case 5:
                    subArea = components[0];
                    area = components[1];
                    app = components[2];
                    break;
                default:
                    throw new Exception("Invalid Xslt URI");
            }

            dict.Add("application", app);
            dict.Add("area", area);
            dict.Add("subArea", subArea);
            dict.Add("xmlPreTransform", String.Format("{0}", useXmlPre));
        }

        return dict;
    }

    public override System.Net.ICredentials Credentials
    {
        set { /* TODO: check if we need credentials */ }
    }

    public override object GetEntity(Uri absoluteUri, string role, Type ofObjectToReturn)
    {
        /*
         *  db://<app>.hist.org
         *  db://<area>.<app>.hist.org
         *  db://<subArea>.<area>.<app>.hist.org
         * 
         * */

        Tracing.TraceHelper.WriteLine(String.Format("GetEntity {0}", absoluteUri));

        XmlReader reader = null;

        switch (absoluteUri.Scheme)
        {
            case "db":
                string origString = absoluteUri.OriginalString;
                IDictionary<string, string> xsltDict = GetUriComponents(origString);

                if(String.IsNullOrWhiteSpace(xsltDict["area"]))
                {
                    reader = DatabaseServiceFactory.DatabaseService.GetApplicationXslt(xsltDict["application"]);
                }
                else if (!String.IsNullOrWhiteSpace(xsltDict["area"]) && String.IsNullOrWhiteSpace(xsltDict["subArea"]) && !Boolean.Parse(xsltDict["xmlPreTransform"]))
                {
                    reader = DatabaseServiceFactory.DatabaseService.GetAreaXslt(xsltDict["application"], xsltDict["area"]);
                }
                else if (!String.IsNullOrWhiteSpace(xsltDict["area"]) && !String.IsNullOrWhiteSpace(xsltDict["subArea"]))
                {
                    if(Boolean.Parse(xsltDict["xmlPreTransform"]))
                        reader = DatabaseServiceFactory.DatabaseService.GetSubareaXmlPreTransformXslt(xsltDict["application"], xsltDict["area"], xsltDict["subArea"]);
                    else
                        reader = DatabaseServiceFactory.DatabaseService.GetSubareaXslt(xsltDict["application"], xsltDict["area"], xsltDict["subArea"]);
                }
                return reader;

            default:
                return base.GetEntity(absoluteUri, role, ofObjectToReturn);
        }
    }

public interface IDatabaseService
{
    ...
    XmlReader GetApplicationXslt(String applicationName);
    XmlReader GetAreaXslt(String applicationName, String areaName);
    XmlReader GetSubareaXslt(String applicationName, String areaName, String subAreaName);
    XmlReader GetSubareaXmlPreTransformXslt(String applicationName, String areaName, String subAreaName);
}

最佳答案

简短回答：
您的IDatabaseService接口方法返回XmlReader对象。在构造这些函数时，请确保将abaseUri传递给构造函数；例如：

public XmlReader GetApplicationXslt(string applicationName)
{
    …
    var baseUri = string.Format("db://{0}.hist.org", applicationName);
    return XmlReader.Create(input: …, 
                            settings: …,
                            baseUri: baseUri);  // <-- this one is important!
}

<?xml version="1.0"?>
<configuration>
  <connectionStrings>
    <add name="SqlServerDatabase"
         connectionString="Data Source=.\SQLEXPRESS;
                           AttachDbFilename=|DataDirectory|\SqlServerDatabase.mdf;
                           Integrated Security=True;
                           User Instance=True"
         />
  </connectionStrings>
</configuration>

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using System.IO;
using System.Xml;

class SqlServerDatabaseService : IDatabaseService
{
    // creates a connection based on connection string from App.config: 
    SqlConnection CreateConnection()
    {
        return new SqlConnection(connectionString: ConfigurationManager.ConnectionStrings["SqlServerDatabase"].ConnectionString);
    }

    // stores an XML document into the 'ApplicationDocuments' table: 
    public void StoreApplicationDocument(string applicationName, XmlReader document)
    {
        using (var connection = CreateConnection())
        {
            SqlCommand command = connection.CreateCommand();
            command.CommandText = "INSERT INTO ApplicationDocuments (ApplicationName, Document) VALUES (@applicationName, @document)";
            command.Parameters.Add(new SqlParameter("@applicationName", applicationName));
            command.Parameters.Add(new SqlParameter("@document", new SqlXml(document)));
                                                             //  ^^^^^^^^^^^^^^^^^^^^
            connection.Open();
            int numberOfRowsInserted = command.ExecuteNonQuery();
            connection.Close();
        }
    }

    // reads an XML document from the 'ApplicationDocuments' table:
    public XmlReader GetApplicationXslt(string applicationName)
    {
        using (var connection = CreateConnection())
        {
            SqlCommand command = connection.CreateCommand();
            command.CommandText = "SELECT Document FROM ApplicationDocuments WHERE ApplicationName = @applicationName";
            command.Parameters.Add(new SqlParameter("@applicationName", applicationName));

            connection.Open();
            var plainXml = (string)command.ExecuteScalar();
            connection.Close();

            if (plainXml != null)
            {
                return XmlReader.Create(new StringReader(plainXml));
            }
            else
            {
                throw new KeyNotFoundException(message: string.Format("Database does not contain a application document named '{0}'.", applicationName));
            }
        }
    }

    … // (all other methods throw a NotImplementedException)
}

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:template match="Foo">
    <Bar/>
  </xsl:template>
</xsl:stylesheet>

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:import href="db://common.hist.org"/>
</xsl:stylesheet>

<?xml version="1.0" encoding="utf-8" ?>
<Foo/>

using System;
using System.Text;
using System.Xml;
using System.Xml.Xsl;

class Program
{
    static void Main(string[] args)
    {
        var databaseService = new SqlServerDatabaseService();

        // put CommonHistOrg.xslt into the 'ApplicationDocuments' database table:
        databaseService.StoreApplicationDocument(
            applicationName: "common",
            document:        XmlReader.Create("CommonHistOrg.xslt"));

        // load the XSLT stylesheet:
        var xslt = new XslCompiledTransform();
        xslt.Load(@"TestStylesheet.xslt", 
            settings: XsltSettings.Default, 
            stylesheetResolver: new XmlDbResolver(databaseService));

        // load the XML test input:
        var input = XmlReader.Create("TestInput.xml");

        // transform the test input and store the result in 'output':
        var output = new StringBuilder();
        xslt.Transform(input, XmlWriter.Create(output));

        // display the transformed output:
        Console.WriteLine(output.ToString());
        Console.ReadLine();
    }
}

databaseService.StoreApplicationDocument(
    applicationName: "test",
    document:        XmlReader.Create("TestStylesheet.xslt"));

xslt.Load(@"TestStylesheet.xslt", …);

xslt.Load(@"db://test.hist.org", …);

关于c# - XslCompiledTransform和自定义XmlUrlResolver:“具有相同键的条目已存在”，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11864564/