Question

I’m working on a RESTful web-service with the WCF Web API. Another party provided the XSD files. I generated the C# classes with xsd.exe. However the schema contains one complex type that I’m having an issue with:

<xs:complexType name="SearchableField">
    <xs:choice>
        <xs:element name="NumericValue" type="xs:float" minOccurs="1" maxOccurs="1"/>
        <xs:element name="BooleanValue" type="xs:boolean" minOccurs="1" maxOccurs="1"/>
    </xs:choice>
    <xs:attribute name="type" type="SearchableFieldType" use="required"/>
</xs:complexType>

This is the generated code for the complex type:

[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.1")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
public partial class SearchableField {

    private object itemField;

    private string typeField;

    /// <remarks/>
    [System.Xml.Serialization.XmlElementAttribute("BooleanValue", typeof(bool), Form=System.Xml.Schema.XmlSchemaForm.Unqualified)]
    [System.Xml.Serialization.XmlElementAttribute("NumericValue", typeof(float), Form=System.Xml.Schema.XmlSchemaForm.Unqualified)]
    public object Item {
        get {
            return this.itemField;
        }
        set {
            this.itemField = value;
        }
    }

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

Question: How to initialize type Item property – which is a plain object – so that it can be serialized according to the schema.

Constraint: The schema is already specified so I may not change the XSD file.

Here’s an example of the XML element how it is expected to look like:

<SearchableFields>
    <SearchableField type="MEGAPIXELS">
        <NumericValue>12</NumericValue>
    </SearchableField>
    <SearchableField type="WEATHER_RESISTANT">
        <BooleanValue>true</BooleanValue>
    </SearchableField>
    <SearchableField type="WATER_RESISTANT">
        <BooleanValue>false</BooleanValue>
    </SearchableField>
</SearchableFields>

Answer 1

(comments)

When I try it like this, it can not be serialized:

var field = new SearchableField { type = "monitor_size", Item = 5 };

Indeed – NumericValue is declared as float in the xml / C#, and using an int is going to introduce an invalid cast; this works, however:

var field = new SearchableField { type = "monitor_size", Item = 5F };

with output:

<SearchableField type="monitor_size">
  <NumericValue>5</NumericValue>
</SearchableField>