Serialize a Bitmap in C#/.NET to XML

Question

I want to XML-Serialize a complex type (class), that has a property of type System.Drawing.Bitmap among others.

    /// <         


        

Answer 1

The BitMap class has not been designed to be easily XML Serialized. So, no, there's not simple way to correct a design decision.

Answer 2

You can also to implement ISerializable and to use SerializationInfo to deal manually with your bitmap content.

EDIT: João is right: Correct way to deal with XML serialization is to implement IXmlSerializable, not ISerializable:

public class MyImage : IXmlSerializable
{
    public string Name  { get; set; }
    public Bitmap Image { get; set; }

    public System.Xml.Schema.XmlSchema GetSchema()
    {
        throw new NotImplementedException();
    }

    public void ReadXml(System.Xml.XmlReader reader)
    {
        throw new NotImplementedException();
    }

    public void WriteXml(System.Xml.XmlWriter writer)
    {
        writer.WriteStartElement("Name");
        writer.WriteString(this.Name);
        writer.WriteEndElement();

        using(MemoryStream ms = new MemoryStream())
        {
            this.Image.Save(ms, ImageFormat.Bmp );
            byte[] bitmapData = ms.ToArray();
            writer.WriteStartElement("Image");
            writer.WriteBase64(bitmapData, 0, bitmapData.Length);
            writer.WriteEndElement();
        }
    }
}

Answer 3

Implement IXmlSerializable and then handle all the serialization details yourself.

Since you say it's a large type and you only have a problem with the bitmap consider doing something like this:

public class BitmapContainer : IXmlSerializable
{
    public BitmapContainer() { }

    public Bitmap Data { get; set; }

    public XmlSchema GetSchema()
    {
        throw new NotImplementedException();
    }

    public void ReadXml(XmlReader reader)
    {
        throw new NotImplementedException();
    }

    public void WriteXml(XmlWriter writer)
    {
        throw new NotImplementedException();
    }
}

public class TypeWithBitmap
{
    public BitmapContainer MyImage { get; set; }

    public string Name { get; set; }
}

Answer 4

I would do something like:

[XmlIgnore]
public Bitmap LargeIcon { get; set; }

[Browsable(false),EditorBrowsable(EditorBrowsableState.Never)]
[XmlElement("LargeIcon")]
public byte[] LargeIconSerialized
{
    get { // serialize
        if (LargeIcon == null) return null;
        using (MemoryStream ms = new MemoryStream()) {
            LargeIcon.Save(ms, ImageFormat.Bmp);
            return ms.ToArray();
        }
    }
    set { // deserialize
        if (value == null) {
            LargeIcon = null;
        } else {
            using (MemoryStream ms = new MemoryStream(value)) {
                LargeIcon = new Bitmap(ms);
            }
        }
    }
}