Dynamic Xaml

XamlUtils.cs

using Sys = System;
using SysIO = System.IO;
using SysWinMarkup = System.Windows.Markup;
using SysXml = System.Xml;
using SysXmlLinq = System.Xml.Linq;

public static class XamlUtils {
    public static object GetXamlObject(string source) {
        SysXml.XmlDocument _xmlDocument = new SysXml.XmlDocument();
        _xmlDocument.LoadXml(source);

        return Xaml.GetXamlObject(_xmlDocument);
    }

    public static object GetXamlObject(SysXml.XmlDocument xmlDocument) {
        const string xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation";
        const string xmlns_x = "http://schemas.microsoft.com/winfx/2006/xaml";

        if(string.IsNullOrEmpty(xmlDocument.DocumentElement.GetAttribute("xmlns"))) {
            xmlDocument.DocumentElement.SetAttribute("xmlns", xmlns);
        }

        if(string.IsNullOrEmpty(xmlDocument.DocumentElement.GetAttribute("xmlns:x"))) {
            xmlDocument.DocumentElement.SetAttribute("xmlns:x", xmlns_x);
        }

        SysIO.TextReader _stringReader = new SysIO.StringReader(xmlDocument.OuterXml);
        SysXml.XmlReader _xmlReader = new SysXml.XmlTextReader(_stringReader);
        return SysWinMarkup.XamlReader.Load(_xmlReader);
    }
}

XamlUtilsSample.cs

System.Windows.Controls.Grid _gridObject = XamlUtils.GetXamlObject("<grid><textblock>ok</textblock></grid>") as System.Windows.Controls.Grid;
this.Content = _gridObject;