Question

I’m working on a WP7 app which gets and updates data on a web server. If any updates need a response, I get a list of errors that needs to be dealt with, and a list of possible choices for each error. The issue I’m having is assigning each object its appropriate list of choices. As of now I get a list of errors, and another list of all possible choices for all errors. I’d like the error object to contain the list of only its options so I can handle that.

So here’s an example response:

<?xml version="1.0" encoding="utf-8"?>
<response xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <response_error_dialogs>
        <error_dialog_list>
            <error_dialog_choice>
                <error_dialog_id>1301</error_dialog_id>
                <error_dialog_message>You have changed the phone number.  Select which phone number to make the primary contact number.</error_dialog_message>
                <error_dialog_title>Phone Number Changed</error_dialog_title>
                <error_dialog_is_set>false</error_dialog_is_set>
                <error_dialog_choice_option_list>
                    <error_dialog_choice_option>
                        <error_dialog_choice_option_id>1</error_dialog_choice_option_id>
                        <error_dialog_choice_option_title>Home</error_dialog_choice_option_title>
                    </error_dialog_choice_option>
                    <error_dialog_choice_option>
                        <error_dialog_choice_option_id>2</error_dialog_choice_option_id>
                        <error_dialog_choice_option_title>Mobile</error_dialog_choice_option_title>
                    </error_dialog_choice_option>
                    <error_dialog_choice_option>
                        <error_dialog_choice_option_id>3</error_dialog_choice_option_id>
                        <error_dialog_choice_option_title>Work</error_dialog_choice_option_title>
                    </error_dialog_choice_option>
                </error_dialog_choice_option_list>
            </error_dialog_choice>
            <error_dialog_choice>
                <error_dialog_id>1303</error_dialog_id>
                <error_dialog_message>You have changed the account email address.  Would you like this to be the new default email?</error_dialog_message>
                <error_dialog_title>Email Address Changed</error_dialog_title>
                <error_dialog_is_set>false</error_dialog_is_set>
                <error_dialog_choice_option_list>
                    <error_dialog_choice_option>
                        <error_dialog_choice_option_id>1</error_dialog_choice_option_id>
                        <error_dialog_choice_option_title>No</error_dialog_choice_option_title>
                    </error_dialog_choice_option>
                    <error_dialog_choice_option>
                        <error_dialog_choice_option_id>2</error_dialog_choice_option_id>
                        <error_dialog_choice_option_title>Yes</error_dialog_choice_option_title>
                    </error_dialog_choice_option>
                </error_dialog_choice_option_list>
            </error_dialog_choice>
        </error_dialog_list>
    </response_error_dialogs>
</response>

And here’s the classes used:

public class ErrorDialog
{
    XElement self;

    public ErrorDialog() { }

    public ErrorDialog(XElement errorDialog)
    {
        self = errorDialog;
    }

    public int errorDialogId
    {
        get { return (int)(self.Element("error_dialog_id")); }
    }
    public string errorDialogMessage
    {
        get { return (string)(self.Element("error_dialog_message")); }
    }
    public string errorDialogTitle
    {
        get { return (string)(self.Element("error_dialog_title")); }
    }
    public bool errorDialogIsSet
    {
        get { return (bool)(self.Element("error_dialog_is_set")); }
    }
    public List<ErrorDialogChoice> errorDialogChoice
    {
        get { return (List<ErrorDialogChoice>)(errorDialogChoice); }
    }
    public int errorDialogSelectedOption
    {
        get { return (int)(self.Element("error_dialog_selected_option")); }
    }
}

class ErrorDialogChoice
{
    XElement self;

    public ErrorDialogChoice() { }

    public ErrorDialogChoice(XElement errorDialogChoice)
    {
        self = errorDialogChoice;
    }

    public int errorDialogChoiceOptionId
    {
        get { return (int)(self.Element("error_dialog_choice_option_id")); }
    }
    public string errorDialogChoiceOptionTitle
    {
        get { return (string)(self.Element("error_dialog_choice_option_title")); }
    }
}

And here’s how I’m parsing it:

XElement response = XElement.Parse(data);  

ErrorDialog[] dialogs = response
    .Element("response_error_dialogs")
    .Element("error_dialog_list")
    .Elements("error_dialog_choice")
    .Select(e => new ErrorDialog(e))
    .ToArray();

ErrorDialogChoice[] edChoices = response
    .Element("response_error_dialogs")
    .Element("error_dialog_list")
    .Element("error_dialog_choice")
    .Element("error_dialog_choice_option_list")
    .Elements("error_dialog_choice_option")
    .Select(e => new ErrorDialogChoice(e))
    .ToArray();

So with this example, the first error_dialog_choice object will have a List containing 3 error_dialog_choice_option objects, the second has the two error_dialog_choice_option objects, and any more that may come back. Any help is appreciated. Thanks.

Answer 1

You can use XML serialization to achieve this much easier:

var reader = new StringReader(xmlString);
var ser = new XmlSerializer(typeof(Response));
var result = (Response) ser.Deserialize(reader);

Using these class definitions.

[XmlType("response")]
public class Response
{
    [XmlElement("response_error_dialogs")]
    public ErrorDialog ErrorDialog;
}

[XmlType("response_error_dialogs")]
public class ErrorDialog
{
    [XmlArray("error_dialog_list")]
    public List<ChoiceErrorDialog> ChoiceList;
}

[XmlType("error_dialog_choice")]
public class ChoiceErrorDialog
{
    [XmlElement("error_dialog_id")]
    public int Id;

    [XmlElement("error_dialog_message")]
    public string Message;

    [XmlElement("error_dialog_title")]
    public string Title;

    [XmlElement("error_dialog_is_set")]
    public bool IsSet;

    [XmlArray("error_dialog_choice_option_list")]
    public List<Option> OptionList;
}

[XmlType("error_dialog_choice_option")]
public class Option
{
    [XmlElement("error_dialog_choice_option_id")]
    public int Id;

    [XmlElement("error_dialog_choice_option_title")]
    public string Title;
}

I am guessing there can be more types of error dialogs, and <error_dialog_choice> is just one of the possible types. In this case you could use subclassing, and list the subclasses with XmlArrayItem attributes.

---

You could also generate the class definitions with xsd.exe or svcutil.exe, from an .xsd or .wsdl file. xsd.exe can even infer the schema from a sample .xml file.

xsd.exe /?
svcutil.exe /?