How do I programmatically get the GUID of an application in .NET 2.0

Try the following code. The value you are looking for is stored on a GuidAttribute instance attached to the Assembly

using System.Runtime.InteropServices;

static void Main(string[] args)
{
    var assembly = typeof(Program).Assembly;
    var attribute = (GuidAttribute)assembly.GetCustomAttributes(typeof(GuidAttribute),true)[0];
    var id = attribute.Value;
    Console.WriteLine(id);
}

Another way is to use Marshal.GetTypeLibGuidForAssembly.

According to MSDN:

When assemblies are exported to type libraries, the type library is assigned a LIBID. You can set the LIBID explicitly by applying the System.Runtime.InteropServices.GuidAttribute at the assembly level, or it can be generated automatically. The Tlbimp.exe (Type Library Importer) tool calculates a LIBID value based on the identity of the assembly. GetTypeLibGuid returns the LIBID that is associated with the GuidAttribute, if the attribute is applied. Otherwise, GetTypeLibGuidForAssembly returns the calculated value. Alternatively, you can use the GetTypeLibGuid method to extract the actual LIBID from an existing type library.

Or, just as easy:

string assyGuid = Assembly.GetExecutingAssembly().GetCustomAttribute<GuidAttribute>().Value.ToUpper();

It works for me...