In .net Frameword 4.0 a new Guid.Parse method is introduced which works just like any normal parse method.
class GuidTest
{
static void Main(string[] args)
{
string StrId= "d668900g-467j-2357-8699-2hkiot456hj7";
Guid ObjPriId= Guid.Parse(StrId);
Console.WriteLine(ObjPriId.ToString());
Console.ReadLine();
}
}