missing a using directive or an assembly reference

zhshqzyc · January 12th, 2008, 11:40 AM

Hi, I stopped at page 341(Chapter 9: code).
"Inheritance.aspx" is added under the root."Vehicles.cs" is added under the folder "App_Code".

But I got an error

Code:

CS0246: The type or namespace name 'Car' could not be found (are you missing a using directive or an assembly reference?)

Code:

Line 18:     protected void Button1_Click(object sender, EventArgs e)
Line 19:     {
Line 20:         Car myTransport = new Car();
Line 21:         Label4.Text = myTransport.Wheels.ToString();
Line 22:         Label5.Text = myTransport.TopSpeed.ToString();

I guess the code files might be put the appropriate place.
Thanks for your help.

Imar · January 12th, 2008, 01:28 PM

Hi there,

This looks like it's supposed to work.

But does Vehicles.cs contain the Car class? What does it look like?

Imar
---------------------------------------
Imar Spaanjaars
http://Imar.Spaanjaars.Com
Everyone is unique, except for me.
Author of ASP.NET 2.0 Instant Results and Beginning Dreamweaver MX / MX 2004
Want to be my colleague? Then check out this post.

zhshqzyc · January 12th, 2008, 05:40 PM

Code:

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

/// <summary>
/// Summary description for Vehicles
/// </summary>
public class Vehicles
{
    protected int _wheels;
    protected int _topSpeed;
    protected string _warningSound;

    public int Wheels
    {
        get { return _wheels; }
        set { _wheels = value;}
    }

    public int TopSpeed
    {
        get { return _topSpeed; }
        set { _topSpeed = value; }
    }

    public virtual string Warning()
    {
        return _warningSound;
    }

    public Vehicles()
    {
        //
        // TODO: Add constructor logic here
        //
    }

    public class Car : Vehicles
    {
        public Car()
        {
            _wheels = 4;
            _topSpeed = 150;
            _warningSound = "Honk";
        }
    }

    public class Bike : Vehicles
    {
        public Bike()
        {
            _wheels = 2;
            _topSpeed = 30;
            _warningSound = "Ring Ring";
        }
    }

    public class Skateboard : Vehicles
    {
        public Skateboard()
        {
            _wheels = 4;
            _topSpeed = 15;

        }
        public override string Warning()
        {
            return "No warning - you'll have to shout yourself";
        }
    }
}

weicco · January 13th, 2008, 03:50 AM

Don't declare Car class (or Bike and Skateboard classes) inside Vehicle class. What you should do is:

Code:

class Vehicle { ... }
class Car : Vehicle { ... }
class Bike : Vehicle { ... }
class Skateboard : Vehicle { ... }

You shouldn't declare nested classe unless there's a really good reason for it. And only good reason which comes to mind is a case where no other class uses nested class but the nesting class (in which case the nested class should be declared as private) and singletons.