Proper way to use a repository class in an webforms aspx.cs file ASP.NET Web forms

Question

What's the proper way to instantiate an instance of a repository class in a code behind file in ASP.NET Web forms aspx.cs file. I've tried doing it the same way that you'd do it in a MVC Controller but it seems like I'm missing out on something. This is what I've tried so far with no luck.

public partial class Ajax : System.Web.UI.Page
{
    private Repository _repo;

    public Ajax()
    {
        _repo = new Repository();
    }

    protected void Page_Load(object sender, EventArgs e)
    {
    }

    [System.Web.Services.WebMethod]
    [ScriptMethod(ResponseFormat = ResponseFormat.Json)]
    public static string CreateForm(object data)
    {
        _repo.Insert(data);
    }
}

public class Repository()
{
    public void Insert(object data)
    {
         //do something.
    }
}

The problem is that visual studio gives me the following error when I try to build it: "An object reference is required for the non-static field, method, or property Ajax._repo" What's the proper way to give static webmethod access to an instance of the Repository class?

EDIT: To Clarify, What's the best way to use an instance of a repository inside static methods?

Answer 1

Web methods must be static. They can't access instance members. You can just grab the repository within your static method.

[System.Web.Services.WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
public static string CreateForm(object data)
{
    Repository repo = new Repository();
    repo.Insert(data);
}

Or better yet, abandon WebMethod and instead start making use of Web API in your project, utilize Dependency Injection.