get data from resources

[SOS]

Hi guys , i have a resource file in my project (Res.resx)
i use of this code to read data from this file :

ResourceManager rs = new ResourceManager
("Res",System.Reflection.Assembly.GetExecutingAssembly());
Response.Write(rs.GetString("Test"));

but i get this error :
Could not find any resources appropriate for the specified culture (or the
neutral culture) in the given assembly ...