Deserialize Xml Using XmlReader and Class from xsd.exe

Question

OK I have hit a snag trying to learn XmlSerializer while going through some tutorials. I have followed all the recommended steps but my program is not returning anything, or is returning null. I created an XML file as follows:

<?xml version='1.0' encoding='UTF-8' ?>
<WeeklyJobs>
   <DailyJobs Date = "02/03/2012"/>
  <DailyJobs Date = "02/04/2012" TotalJobs = "2">
    <Jobs>
      <Job JobName = "Job Name" Description = "Description"/>
      <Job JobName = "Job Name" Description = "Description"/>
    </Jobs>
  </DailyJobs>
  <DailyJobs Date = "02/05/2012" TotalJobs = "1">
    <Jobs>
      <Job JobName = "Job Name" Description = "Description"/>
    </Jobs>
  </DailyJobs>
  <DailyJobs Date = "02/06/2012" TotalJobs = "2">
    <Jobs>
      <Job JobName = "Job Name" Description = "Description"/>
      <Job JobName = "Job Name" Description = "Description"/>
    </Jobs>
  </DailyJobs>
  <DailyJobs Date = "02/07/2012"/>
  <DailyJobs Date = "02/08/2012" TotalJobs = "2">
    <Jobs>
      <Job JobName = "Job Name" Description = "Description"/>
      <Job JobName = "Job Name" Description = "Description"/>
    </Jobs>
  </DailyJobs>
</WeeklyJobs>

I then used xsd.exe to generate the .xsd file which is:

<?xml version="1.0" encoding="utf-8"?>
<xs:schema id="WeeklyJobs" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema"     xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
  <xs:element name="WeeklyJobs" msdata:IsDataSet="true" msdata:UseCurrentLocale="true">
    <xs:complexType>
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <xs:element name="DailyJobs">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="Jobs" minOccurs="0" maxOccurs="unbounded">
                <xs:complexType>
                  <xs:sequence>
                    <xs:element name="Job" minOccurs="0" maxOccurs="unbounded">
                      <xs:complexType>
                        <xs:attribute name="JobName" type="xs:string" />
                        <xs:attribute name="Description" type="xs:string" />
                      </xs:complexType>
                    </xs:element>
                  </xs:sequence>
                </xs:complexType>
              </xs:element>
            </xs:sequence>
            <xs:attribute name="Date" type="xs:string" />
            <xs:attribute name="TotalJobs" type="xs:string" />
          </xs:complexType>
        </xs:element>
      </xs:choice>
    </xs:complexType>
  </xs:element>
</xs:schema>

After creating the schema I used xsd.exe again to auto generate the class for me which is:

/// <remarks/>
[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 WeeklyJobs
{

    private WeeklyJobsDailyJobs[] itemsField;

    /// <remarks/>
    [System.Xml.Serialization.XmlElementAttribute("DailyJobs", Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
    public WeeklyJobsDailyJobs[] Items
    {
        get
        {
            return this.itemsField;
        }
        set
        {
            this.itemsField = value;
        }
    }
}

/// <remarks/>
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "2.0.50727.3038")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
public partial class WeeklyJobsDailyJobs
{

    private WeeklyJobsDailyJobsJobsJob[][] jobsField;

    private string dateField;

    private string totalJobsField;

    /// <remarks/>
    [System.Xml.Serialization.XmlArrayAttribute(Form = System.Xml.Schema.XmlSchemaForm.Unqualified)]
    [System.Xml.Serialization.XmlArrayItemAttribute("Job", typeof(WeeklyJobsDailyJobsJobsJob), Form = System.Xml.Schema.XmlSchemaForm.Unqualified, IsNullable = false)]
    public WeeklyJobsDailyJobsJobsJob[][] Jobs
    {
        get
        {
            return this.jobsField;
        }
        set
        {
            this.jobsField = value;
        }
    }

    /// <remarks/>
    [System.Xml.Serialization.XmlAttributeAttribute()]
    public string Date
    {
        get
        {
            return this.dateField;
        }
        set
        {
            this.dateField = value;
        }
    }

    /// <remarks/>
    [System.Xml.Serialization.XmlAttributeAttribute()]
    public string TotalJobs
    {
        get
        {
            return this.totalJobsField;
        }
        set
        {
            this.totalJobsField = value;
        }
    }
}

/// <remarks/>
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "2.0.50727.3038")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType = true)]
public partial class WeeklyJobsDailyJobsJobsJob
{

    private string jobNameField;

    private string descriptionField;

    /// <remarks/>
    [System.Xml.Serialization.XmlAttributeAttribute()]
    public string JobName
    {
        get
        {
            return this.jobNameField;
        }
        set
        {
            this.jobNameField = value;
        }
    }

    /// <remarks/>
    [System.Xml.Serialization.XmlAttributeAttribute()]
    public string Description
    {
        get
        {
            return this.descriptionField;
        }
        set
        {
            this.descriptionField = value;
        }
    }
}

After this I added the .CS file to my project and created a simple winform with a TextBox to display some data once I have deserialized some xml. Like I said the program launches and nothing is displayed in the TextBox and no Exceptions are thrown. Here is my winform:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

    }

    public string getExample()
    {
        XmlSerializer serializer = new XmlSerializer(typeof(WeeklyJobs));
        WeeklyJobs jobs;
        string xml = @"<?xml version = ""1.0""?>"
            + @"<WeeklyJobs>"
            + @"<DailyJobs Date = ""02/03/2012""/>"
            + @"<DailyJobs Date = ""02/04/2012"" TotalJobs = ""2"">"
            + @"<Jobs>"
            + @"<Job JobName = ""Job Name"" Description = ""Description""/>"
            + @"<Job JobName = ""Job Name"" Description = ""Description""/>"
            + @"</Jobs>"
            + @"</DailyJobs>"
            + @"</WeeklyJobs>";

        // Create an XmlTextReader
        using (XmlReader reader = XmlReader.Create(new StringReader(xml)))
        {
            jobs = (WeeklyJobs)serializer.Deserialize(reader);
        }

        return jobs.Items[0].Date;

    }

    private void Form1_Load(object sender, EventArgs e)
    {
        textBox1.Text = getExample();

    }


}

I have got much more simple xml examples to work but I the second I try to add some complexity to my xml I fail. I have to figure out how to use the xml I have here. I appreciate the help! Thanks everyone!

Answer 1

Ok, the first problem is that the XmlSerializer constructor is raising an unhandled exception, but that is somehow getting swallowed. This explains why the text box is empty. I set the debugger to break on all CLR exceptions, and found that the constructor was throwing an InvalidOperationException -- apparently during the code generation process:

Unable to generate a temporary class (result=1).

error CS0030: Cannot convert type 'DeleteMe.WeeklyJobsDailyJobsJobsJob[]' to 'DeleteMe.WeeklyJobsDailyJobsJobsJob'

error CS0029: Cannot implicitly convert type 'DeleteMe.WeeklyJobsDailyJobsJobsJob' to 'DeleteMe.WeeklyJobsDailyJobsJobsJob[]'

(The constructor was also throwing a FileNotFound exception, but it also handles that, so you can ignore it.)

It seems the problem is the jagged arrays -- did you change 1-dimensional arrays to jagged arrays? The error message pointed me in that direction, of course, but I have also never seen jagged arrays in xsd-generated code, so it looked suspicious. I changed two occurrences of WeeklyJobsDailyJobsJobsJob[][] to WeeklyJobsDailyJobsJobsJob[] and the application worked just fine.

As an aside, you should use DateTime for your dates, but XML serializer does not support variable date formats (see https://stackoverflow.com/a/1118855/385844 ). If you have no control over the source, you're probably better off converting the strings to dates before you store them in your database or wherever.