How can you clone a WPF object?

Question

The simplest way that I've done it is to use a XamlWriter to save the WPF object as a string. The Save method will serialize the object and all of its children in the logical tree. Now you can create a new object and load it with a XamlReader.

ex: Write the object to xaml (let's say the object was a Grid control):

string gridXaml = XamlWriter.Save(myGrid);

Load it into a new object:

StringReader stringReader = new StringReader(gridXaml);
XmlReader xmlReader = XmlReader.Create(stringReader);
Grid newGrid = (Grid)XamlReader.Load(xmlReader);

In .NET 4.0, the new xaml serialization stack makes this MUCH easier.

var sb = new StringBuilder();
var writer = XmlWriter.Create(sb, new XmlWriterSettings
{
    Indent = true,
    ConformanceLevel = ConformanceLevel.Fragment,
    OmitXmlDeclaration = true,
    NamespaceHandling = NamespaceHandling.OmitDuplicates, 
});
var mgr = new XamlDesignerSerializationManager(writer);

// HERE BE MAGIC!!!
mgr.XamlWriterMode = XamlWriterMode.Expression;
// THERE WERE MAGIC!!!

System.Windows.Markup.XamlWriter.Save(this, mgr);
return sb.ToString();

There are some great answers here. Very helpful. I had tried various approaches for copying Binding information, including the approach outlined in http://pjlcon.wordpress.com/2011/01/14/change-a-wpf-binding-from-sync-to-async-programatically/ but the information here is the best on the Internet!

I created a re-usable extension method for dealing with InvalidOperationException “Binding cannot be changed after it has been used.” In my scenario, I was maintaining some code somebody wrote, and after a major DevExpress DXGrid framework upgrade, it no longer worked. The following solved my problem perfectly. The part of the code where I return the object could be nicer, and I will re-factor that later.

/// <summary>
/// Extension methods for the WPF Binding class.
/// </summary>
public static class BindingExtensions
{
    public static BindingBase CloneViaXamlSerialization(this BindingBase binding)
    {
        var sb = new StringBuilder();
        var writer = XmlWriter.Create(sb, new XmlWriterSettings
        {
            Indent = true,
            ConformanceLevel = ConformanceLevel.Fragment,
            OmitXmlDeclaration = true,
            NamespaceHandling = NamespaceHandling.OmitDuplicates,
        });
        var mgr = new XamlDesignerSerializationManager(writer);

        // HERE BE MAGIC!!!
        mgr.XamlWriterMode = XamlWriterMode.Expression;
        // THERE WERE MAGIC!!!

        System.Windows.Markup.XamlWriter.Save(binding, mgr);
        StringReader stringReader = new StringReader(sb.ToString());
        XmlReader xmlReader = XmlReader.Create(stringReader);
        object newBinding = (object)XamlReader.Load(xmlReader);
        if (newBinding == null)
        {
            throw new ArgumentNullException("Binding could not be cloned via Xaml Serialization Stack.");
        }

        if (newBinding is Binding)
        {
            return (Binding)newBinding;
        }
        else if (newBinding is MultiBinding)
        {
            return (MultiBinding)newBinding;
        }
        else if (newBinding is PriorityBinding)
        {
            return (PriorityBinding)newBinding;
        }
        else
        {
            throw new InvalidOperationException("Binding could not be cast.");
        }
    }
}