The simple way to parse strings to GUIDs in C# or VB.NET

While the religious debate rages between whether we should be using GUIDs as primary keys rages, you can use the Parse method of the System.SqlTypes.SQLGuid class to parse query strings to GUIDs. Here's an example:

return System.Data.SqlTypes.SqlGuid.Parse(Request.QueryString["ParticipantGuid"]).Value;