I have used the SOQL to get the salesforce record.
sforce.SforceService SFDCSer;
qr = SFDCSer.query('select id,name from account');
sforce.sObject[] queryresutls = qr.records;
List<sforce.sObject> recordList = queryresutls.OfType<sforce.sObject>().ToList();
I don't know how to use the SOSL in C#. I cant find the Search.Query keyword.