Question

I’m new to ASP.NET, and I’m trying to create a class that will call in aspx called AddNode.aspx, I have a few questions

1. How do I simply print a text in constructor/method, similar to php echo / java system.out.print()
2. How do I call the class in AddNode.aspx
3. How do I define a function (GetNode()) to return database result?

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


public class category
{
    public category()
    {
        //
        // TODO: Add constructor logic here
        //
        Response.Write("abc");
    }

    public static Array[] GetNode() {

    }
}

Answer 1

There are indeed great differences between PHP and ASP .NET Web Forms (the differences are less in the case of ASP .NET MVC but they are still much) so I understand the source of confusion.

1-Are you using Web Forms? If so, you can add a Label control to the Form and then set it’s Text property to some value you like. label1.Text = “Hello ASP .NET”;

In the ASPX markup:
<asp:label ID="label1" runat="server" text="Label">

In the code behind file (associated with ASPX, right click on the designer and then choose View Code):

    protected void Page_Load(object sender, EventArgs e)
    {
        label1.Text = "Hello ASP .NET";
    }

You can also use Response.Write(“Hello ASP .NET“); But with this you have less control on where this text appears. Notice you can write HTML tags.

2-You have to distinguish between the class that represents the Web Form (exists in the code-behind file, note the ASP .NET term “code-behind”) and other classes such as the one you made: “category” (in .NET it’s a matter of convention that class names are capitalized: Category).

Call a class? If you mean create an instance of a class for some purpose, just write category
instance = new category();. You can refer to static functionality in the class by writing category.StaticMemberName(); if it’s a method.

3-That’s a multifaceted question. Read about Data access in .NET…

You need to do lots of reading before asking questions like these! Good luck.