orktane

const string RESOURCE_PATH = "/{0};component/{1}";   // the format is ==> /AssemblyName;component/ResourceFilePathName

public UIElement LoadXaml(string assemblyFullyQualifiedName, string xamlPathFileName, bool xClassType)
{

    // and we try and load thew resource
    var _uri = new Uri(
        string.Format(RESOURCE_PATH, GetAssemblyName(assemblyFullyQualifiedName), xamlPathFileName), UriKind.Relative);
    var _streamResourceInfo = Application.GetResourceStream(_uri);

    using (var _stream = _streamResourceInfo.Stream)
    {

        return (xClassType ? XamlXClassLoader(_stream, assemblyFullyQualifiedName) : XamlLoader(_stream)) as UIElement;

    }

}

Object XamlLoader(Stream stream)
{
    using (var _reader = new StreamReader(stream))
    {
        return XamlReader.Load(_reader.ReadToEnd());
    }
}
    
Object XamlXClassLoader(Stream stream, string assemblyName)
{

    // we load the content as xml
    using (var _xmlReader = XmlReader.Create(stream))
    {
        // the control should be the root element
        if (_xmlReader.Read())
        {

            // we get the x:Class attribute's value
            var _classTypeName = _xmlReader.GetAttribute("Class", "http://schemas.microsoft.com/winfx/2006/xaml");

            // assembly name is required, else we take the assumption it is the application's assembly
            var _assemblyName = !string.IsNullOrEmpty(assemblyName)
                ? assemblyName : Application.Current.GetType().Assembly.FullName;

            // we load the class type defined in the x:Class attribute
            var _type = Type.GetType(_classTypeName + "," + _assemblyName, false, true);

            // we load the type
            if (_type != null)
            {
                var _xamlControl = Activator.CreateInstance(_type);     // note, the assumption of no args

                // and we return
                return _xamlControl;
            }

        }
    }

    // else
    return null;

}

string GetAssemblyName(string assemblyFullyQualifiedName)
{
    return assemblyFullyQualifiedName.Substring(0, assemblyFullyQualifiedName.IndexOf(','));
}