must declare a body because it is not marked abstract or extern? C#/ASP.NET

Question

I have a normal web form with code behind, in this code behind I can instantiate a couple of classes I have in the root folder, such as:

public partial class _De         


        

Answer 1

public string id { get; set; }

is an automatic property and these were added in C# v3.0 / .Net v3.5, so ensure you are targetting this version or higher in your project settings. If you wish to target an earlier version you'll need to use properties with a backing field.