在 C# 反序列化期间，出现 System.InvalidOperationException: < xmlns=''> 不是预期的

Question

I'm new to XMLdeserialization. I used xsd.exe to generate object classes for performing a deserialization on an existing XML file. When I run my solution below, I get the error

System.InvalidOperationException: < xmlns=''> was not expected

on the s = (NewDataSet)xs.Deserialize(sr) call. I looked this error up on Stack Overflow, and everyone says it's in the XMLRootAttribute line.

[System.Xml.Serialization.XmlRootAttribute(Namespace = "", IsNullable = false)]

How can I correct this line? Or where can I find some documentation that explains how to correct it?

Also, why doesn't xsd.exe generate the correct XmlRootAttribute line in the first place? Am I invoking this utility wrong? Or are there some situations the xsd.exe utility can't handle?

public class Program
{
    static void Main(string[] args)
    {
        SortedSet<string> symbolsEstablished = new SortedSet<string>();

        GetXmlDataSet("Expt 2buy.xml", ref symbolsEstablished);
    }

    public static void GetXmlDataSet(string fileName, ref SortedSet<string> symbols)
    {
        XmlSerializer xs = new XmlSerializer(typeof(NewDataSet));
        StreamReader sr = new StreamReader(@"C:\Users\mehl\AppData\Roaming\Fidelity Investments\WealthLabPro\1.0.0.0\Data\DataSets\" + fileName);
        NewDataSet s = (NewDataSet)xs.Deserialize(sr);
        Console.WriteLine(s.Items[0].DSString);
        sr.Close();
    }

    [System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "2.0.50727.3038")]
    [System.SerializableAttribute()]
    [System.Diagnostics.DebuggerStepThroughAttribute()]
    [System.ComponentModel.DesignerCategoryAttribute("code")]
    [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
    [System.Xml.Serialization.XmlRootAttribute(Namespace = "", IsNullable = false)]
    public partial class DataSet
    {
        private string nameField;
        private string scaleField;
        private string barIntervalField;
        private string dSStringField;
        private string providerNameField;

        [System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
        public string Name
        {
            get { return this.nameField; }
            set { this.nameField = value; }
        }

        [System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
        public string Scale
        {
            get { return this.scaleField; }
            set { this.scaleField = value; }
        }

        [System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
        public string BarInterval
        {
            get { return this.barIntervalField; }
            set { this.barIntervalField = value; }
        }

        [System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
        public string DSString
        {
            get { return this.dSStringField; }
            set { this.dSStringField = value; }
        }

        [System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
        public string ProviderName
        {
            get { return this.providerNameField; }
            set { this.providerNameField = value; }
        }
    }

    [System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "2.0.50727.3038")]
    [System.SerializableAttribute()]
    [System.Diagnostics.DebuggerStepThroughAttribute()]
    [System.ComponentModel.DesignerCategoryAttribute("code")]
    [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
    [System.Xml.Serialization.XmlRootAttribute(Namespace = "", IsNullable = false)]
    public partial class NewDataSet
    {
        private DataSet[] itemsField;

        [System.Xml.Serialization.XmlElementAttribute("DataSet")]
        public DataSet[] Items
        {
            get { return this.itemsField; }
            set { this.itemsField = value; }
        }
    }
}

The entire above code segment is wrapped in a screener2wl namespace.

And here's the XML file I'm trying to deserialize:

<?xml version="1.0"?>
<DataSet xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Name>Expt 2buy</Name>
  <Scale>Daily</Scale>
  <BarInterval>0</BarInterval>
  <DSString>AAL,AFSI,BEN,BIG,BLKB,CDK,COHR,CRUS,EGP,EPE,ETH,FB,HUM,LSTR,MDP,MSI,NYT,TAST,TER,TSO,TXN,UTHR,VASC,VLO,WRI,</DSString>
  <ProviderName>FidelityStaticProvider</ProviderName>
</DataSet>

Answer 1

Using xml linq:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;

namespace ConsoleApplication1
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        static void Main(string[] args)
        {
            XDocument doc = XDocument.Load(FILENAME);

            DataSet ds = doc.Descendants("DataSet").Select(x => new DataSet() {
                nameField = (string)x.Element("Name"),
                scaleField = (string)x.Element("Scale"),
                barIntervalField = (string)x.Element("BarInterval"),
                dSStringField = (string)x.Element("DSString"),
                providerNameField = (string)x.Element("ProviderName")
            }).FirstOrDefault();
        }
    }
    public partial class DataSet
    {
        public string nameField { get; set; }
        public string scaleField { get; set; }
        public string barIntervalField { get; set; }
        public string dSStringField { get; set; }
        public string providerNameField { get; set; }
    }
}

Answer 2

I got to thinking... isn't it odd xsd.exe would provide a code generated solution that defines two independent XmlRootAttribute nodes? Can an XML file even have two Root Nodes? Maybe the solutions xsd.exe generates shouldn't be taken too literally. :-)

So after editing its solution, and removing one part with a second XmlRootAttribute defined, I got the solution below, which works.

namespace screener2wl
{
    public class Program
    {
        static void Main(string[] args)
        {
            SortedSet<string> symbolsEstablished = new SortedSet<string>();
            GetXmlDataSet("Expt 2buy.xml", ref symbolsEstablished);
        }

        public static void GetXmlDataSet(string fileName, ref SortedSet<string> symbols)
        {
            XmlSerializer xs = new XmlSerializer(typeof(DataSet));
            StreamReader sr = new StreamReader(@"C:\Users\mehl\AppData\Roaming\Fidelity Investments\WealthLabPro\1.0.0.0\Data\DataSets\" + fileName);
            DataSet s = (DataSet)xs.Deserialize(sr);
            Console.WriteLine(s.DSString);
            sr.Close();
        }

        [System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
        [System.Xml.Serialization.XmlRootAttribute(IsNullable = false)]
        public class DataSet
        {
            private string nameField;
            private string scaleField;
            private string barIntervalField;
            private string dSStringField;
            private string providerNameField;

            [System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
            public string Name
            {
                get { return this.nameField; }
                set { this.nameField = value; }
            }

            [System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
            public string Scale
            {
                get { return this.scaleField; }
                set { this.scaleField = value; }
            }

            [System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
            public string BarInterval
            {
                get { return this.barIntervalField; }
                set { this.barIntervalField = value; }
            }

            [System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
            public string DSString
            {
                get { return this.dSStringField; }
                set { this.dSStringField = value; }
            }

            [System.Xml.Serialization.XmlElementAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
            public string ProviderName
            {
                get { return this.providerNameField; }
                set { this.providerNameField = value; }
            }
        }
    }
}

Bottom line, use the code solutions xsd.exe generates from your XML data file as a guide, not a truth. It's a great tool, but needs to be used with a grain of salt. ... welcome your comments on my XMLdeserialization problem.