XML De/serialization

The code that de/serializes AAS models from and to XML documents lives in the static class Xmlization.

Serialize

You serialize a model using the static class Xmlization.Serialize by calling its To method on an Environment. The To method writes to a System.Xml.XmlWriter.

Here is an example snippet:

using System.Collections.Generic;

using Aas = AasCore.Aas3_0;
using AasXmlization = AasCore.Aas3_0.Xmlization;

public class Program
{
    public static void Main()
    {
        // Prepare the environment
        var someProperty = new Aas.Property(
            Aas.DataTypeDefXsd.Boolean)
        {
            IdShort = "someProperty",
        };

        var submodel = new Aas.Submodel(
            "some-unique-global-identifier")
        {
            SubmodelElements = new List<Aas.ISubmodelElement>()
            {
                someProperty
            }
        };

        var environment = new Aas.Environment()
        {
            Submodels = new List<Aas.ISubmodel>()
            {
                submodel
            }
        };

        // Serialize to an XML writer
        var outputBuilder = new System.Text.StringBuilder();

        using var writer = System.Xml.XmlWriter.Create(
            outputBuilder,
            new System.Xml.XmlWriterSettings()
            {
                Encoding = System.Text.Encoding.UTF8
            }
        );

        AasXmlization.Serialize.To(
            environment,
            writer
        );
        
        writer.Flush();

        // Print the output
        System.Console.WriteLine(
            outputBuilder.ToString()
        );

        // Outputs (all on a single line):
        // <?xml version="1.0" encoding="utf-16"?>
        // <environment xmlns="https://admin-shell.io/aas/3/0">
        // <submodels><submodel>
        // <id>some-unique-global-identifier</id>
        // <submodelElements><property><idShort>someProperty</idShort>
        // <valueType>xs:boolean</valueType></property></submodelElements>
        // </submodel></submodels></environment>
    }
}

De-serialize

The de-serialization is encapsulated in Xmlization.Deserialize static class. The crucial method is EnvironmentFrom which reads from an System.Xml.XmlReader and re-creates back an instance of Environment.

The methods *From from Xmlization.Deserialize expect the reader to already point to the XML element of the instance. If you have non-content fields, such as an XML declaration, you have to invoke System.Xml.XmlReader.MoveToContent first.

Here is a snippet which parses XML as text and then de-serializes it into an instance of Environment:

using System.Collections.Generic;

using Aas = AasCore.Aas3_0;
using AasXmlization = AasCore.Aas3_0.Xmlization;

public class Program
{
    public static void Main()
    {
        var text = (
            "<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
            "<environment xmlns=\"https://admin-shell.io/aas/3/0\">" +
            "<submodels><submodel>" +
            "<id>some-unique-global-identifier</id>" +
            "<submodelElements><property><idShort>someProperty</idShort>" +
            "<valueType>xs:boolean</valueType></property></submodelElements>" +
            "</submodel></submodels></environment>"
        );

        using var stringReader = new System.IO.StringReader(
            text);

        using var xmlReader = System.Xml.XmlReader.Create(
            stringReader);

        // This step is necessary to skip the non-content. Otherwise,
        // the deserialization would have thrown an exception.
        xmlReader.MoveToContent();

        var environment = AasXmlization.Deserialize.EnvironmentFrom(
            xmlReader);

        // Print the types of the model elements contained
        // in the environment
        foreach (var something in environment.Descend())
        {
            System.Console.WriteLine(something.GetType());
        }

        // Outputs:
        // AasCore.Aas3_0.Submodel
        // AasCore.Aas3_0.Property
    }
}

Errors

If the XML document from System.Xml.XmlReader comes in an unexpected form, our SDK throws a Xmlization.Exception. This can happen, for example, if unexpected XML elements or XML attributes are encountered, or an expected XML element is missing.