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.

Answer 2

do you have TargetFramework = "3.5" for the project ? Check out this post.

Answer 3

public string id { get; set;}

This line is the issue, and the question has been answered above, but I am adding an aswer with code to illustrate how to put in backing fields for those who are new to C#. This an example of what the backing fields would look like, for public string id { get; set; }:

    private string p_id="";
    public string id {
        get {
            return p_id;
        }
        set {
            p_id = value;
        }
    }

Note the initialized private string p_id that holds the actual value for the public string id. Also note that value is defined by the compiler, and is cast as a string in this instance. If the property id was an int instead, value would be cast as an int (integer) instead of a string.