Getting my class to work in asp.net C#

Question

I have created C# classes before in non-web application projects. Normally, All you have to do is add a class file to the project and you can add an instance on the forms, no namespacing or using required. But I noticed in ASP.NET, when you create a class and try to create a instance, i'm getting errors saying the directive or assembly reference missing. I don't understand why? Okay, so most likely I have to take the hard way, and create a class library and use namespacing or add a reference yet STILL the same errors. I'm confused here why I can't seem to get this simple empty class working.

I currently have a class called Class1.cs in my App_code folder. I have an web form called About.aspx.

my class called Class1.cs

 using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Web;
using VideoWebsite;

   namespace VideoWebsite1
  {
       public class Class1
    {

    public Class1()
    {
    }
    public string tag { get; set; }
   }
 }

my web form About.aspx

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
 using System.Web.UI;
 using System.Web.UI.WebControls;
 using System.Data;
 using System.Data.SqlClient;
 using System.Web.Configuration;
 using VideoWebsite1;


  public partial class WebForm4 : System.Web.UI.Page
 {

      protected void Page_Load(object sender, EventArgs e)
      {
           Class1 p = new Class1();
           lbltag.text =(string) p.Tag;
      }
  }

update: Changing Build Action to compile to my class file fixed it. Thank you.

Answer 1

Your problem is here:

using VideoWebsite;

The compiler can't locate it so it's asking for a new reference to an assembly containing that namespace.

If that is a typo and you actually meant VideoWebsite1, you can remove it all together, since that is also the namespace of Class1.

Answer 2

If your Class1 is inside same project then yes you can refer it directly like the way you are intending to do but if you have created the class in a different project then include/add that project reference in your web project referenced dll list.

Then most probably the Build Action of the class is not set to compile . To check the same do below

Right click on the Class1.cs file under App_Code folder and check its Build Action property. If not set then set it accordingly.