It is very easy to convert a string to stream and vice versa in .Net.
Converting String to Stream:
MemoryStream stream = new MemoryStream();
StreamWriter writer = new StreamWriter(stream);
writer.Write(myString);
writer.Flush();
if you already know the encoding of your string, you can also use
byte[] tempByteArray = Encoding.ASCII.GetBytes(myString);
MemoryStream stream = new MemoryStream(tempByteArray);
Converting Stream to String:
StreamReader reader = new StreamReader(stream);
stream.Position = 0;
string [...]