How to output hex numbers via XML Serialization in c#?

I've got a few classes and structures that I use XML serialization to save 开发者_运维百科and recall data, but a feature that I'd like to have is to output integers in hex representation. Is there any attribute that I can hang on these structure to make that happen?

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There's a bit of code smell, but the following will work:

public class ViewAsHex
{
    [XmlIgnore]
    public int Value { get; set; }

    [XmlElement(ElementName="Value")]
    public string HexValue
    {
        get
        {
            // convert int to hex representation
            return Value.ToString("x");
        }
        set
        {
            // convert hex representation back to int
            Value = int.Parse(value, 
                System.Globalization.NumberStyles.HexNumber);
        }
    }
}

Test the class in a console program:

public class Program
{
    static void Main(string[] args)
    {
        var o = new ViewAsHex();
        o.Value = 258986522;

        var xs = new XmlSerializer(typeof(ViewAsHex));

        var output = Console.OpenStandardOutput();
        xs.Serialize(output, o);

        Console.WriteLine();
        Console.WriteLine("Press enter to exit.");
        Console.ReadLine();
    }
}

The result:

<?xml version="1.0"?>
<ViewAsHex xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Value>f6fd21a</Value>
</ViewAsHex>

---

I know, last answer was more than two years ago, but I was looking for have a solution and found this thread. But wasn't satisfied by proposed solutions so I tried to find my own solution:

public struct HInt32 : IXmlSerializable
{
    private int _Value;

    public HInt32(int v) { _Value = v; }

    XmlSchema IXmlSerializable.GetSchema() { return null; }

    void IXmlSerializable.ReadXml(XmlReader reader) { _Value = Int32.Parse(reader.ReadContentAsString().TrimStart('0', 'x'), NumberStyles.HexNumber); }

    void IXmlSerializable.WriteXml(XmlWriter writer) { writer.WriteValue("0x" + _Value.ToString("X2").PadLeft(8, '0')); }

    public static implicit operator int(HInt32 v) { return v._Value; }

    public static implicit operator HInt32(int v) { return new HInt32(v); }
}

Now you can use this type instead of Int32 in your serialized class :

public TestClass
{
    public HInt32 HexaValue { get; set; }
}

public void SerializeClass()
{
    TestClass t = new TestClass();
    t.HexaValue = 6574768; // Transparent int assigment

    XmlSerializer xser = new XmlSerializer(typeof(TestClass));
    StringBuilder sb = new StringBuilder();
    using(StringWriter sw = new StringWriter(sb))
    {
        xser.Serialize(sw, t);
    }
    Console.WriteLine(sb.ToString());
}

The result is :

<?xml version="1.0" encoding="utf-16"?>
<TestClass xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <HexaValue>0x006452B0</HexaValue>
</TestClass>

You can adapt the solution to get the exact format you want and complete the HInt32 struct to be more "Int32 complient". Warning : This solution can't be use to serialize a property as an attribute.

---

You can implement fully custom serialization, but that's probably a bit much for this. How about exposing a property MyIntegerAsHex, that returns the integer as a string, formatted as a hexadecimal number: MyInteger.ToString("X"); The property will need a setter, even though it's a calculated field, so that the string from the serialized object can be fed into a new instance on deserialization.

You can then implement a deserialization callback, or just put code in the setter, that will parse the hex number to a decimal integer when the object is deserialized: MyInteger = int.Parse(IntegerAsHex, NumberStyles.AllowHexNumber);

So, in summary, your property would look something like this:

public string MyIntegerAsHex
{
   get { return MyInteger.ToString("X"); }
   set { MyInteger = int.Parse(value, NumberStyles.AllowHexNumber); }
}

Then, if you didn't want to see the number as a decimal integer in the XML file, just tag it with [XmlIgnore].

---

I came up with a slightly improved variant of the workaround from KeithS and code4life.

using System;
using System.Linq;

public class Data
{
    [XmlIgnore()]
    public uint Value { get; set; }
    [XmlAttribute("Value", DataType = "hexBinary")]
    public byte[] ValueBinary
    {
        get
        {
            return BitConverter.GetBytes(Value).Reverse().ToArray();
        }
        set
        {
            Value = BitConverter.ToUInt32(value.Reverse().ToArray(), 0);
        }
    }
}

The benefit of this is that the xsd.exe tool will set the type attribute to xs:hexBinary instead of xs:string...

<?xml version="1.0" encoding="utf-8"?>
<xs:schema elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="Data" nillable="true" type="Data" />
  <xs:complexType name="Data">
    <xs:attribute name="Value" type="xs:hexBinary" />
  </xs:complexType>
</xs:schema>