ParsingCSDL.cs

IEdmModel model;
Func<Uri, XmlReader> getReferencedSchemaFunc = uri =>
{
  if (uri.AbsoluteUri.EndsWith("ReferencedModel.csdl"))
  {
    return XmlReader.Create(File.Open("ReferencedModel.csdl", FileMode.Open));
  }
  else
  {
    return null;
  }
};

using (Stream csdlStream = File.Open("MainModel.csdl", FileMode.Open))
{
  bool parseResult;
  IEnumerable<EdmError> errors;
  parseResult = EdmxReader.TryParse(XmlReader.Create(csdlStream), getReferencedSchemaFunc, out model, out errors);
  if (!parseResult)
  {
    throw new InvalidOperationException("Failed to load model : " + string.Join(Environment.NewLine, errors.Select(e => e.ErrorMessage)));
  }
}