try{} cacth{} ,make it useful!

Microsoft CRM Platform will only throw SoapException whose message property is always "Server was unable to process request.". So we definitely need it in our catch{} try{} .
Plus, if we want to catch SqlException, we need catch it as well. Or to use a common Exception to catch everything!

catch (System.Web.Services.Protocols.SoapException ex)
{ 
    TextWriter log = TextWriter.Synchronized(File.AppendText(@"C:\CRM_Debug\error.txt"));
    log.WriteLine("SoapException: " + DateTime.Now.ToString());
    log.WriteLine("Error Message: " + ex.Detail.InnerText);
    XmlDocument error = new XmlDocument();
    error.LoadXml(ex.Detail.InnerXml);
    log.WriteLine("Error Code: " + error.SelectSingleNode("/error/code").InnerText);
    log.WriteLine("Error Description: " + error.SelectSingleNode("/error/description").InnerText);
    log.WriteLine("Error Type: " + error.SelectSingleNode("/error/type").InnerText);
    log.WriteLine();
    log.Close();
}
catch (SqlException ex) 
{
    //
}
catch (Exception ex) 
{
    //
}