Pablo,

>I've tried with WriteXml() but I can't make it work property, can you tell me a code example?<

Well, what problem are you having making it work? This should do the trick (this is untested code):

// Assume MyDataSet contains the Table that your Grid is bound to
// Also, I'm assuming that you want this in a string, rather than a File
StringWriter sw = new StringWriter();
MyDataSet.WriteXML(sw, XmlWriteMode.DiffGram);
string MyDiffGram = sw.ToString();

HTH,
~~Bonnie