What is ASP.NET Web Forms?
ASP.NET Web Forms is a programming model supported by Microsoft’s ASP.NET technology for creating dynamic web applications and websites.
It is built on the Microsoft .NET Framework, which provides all its benefits, including a managed environment, type safety, and inheritance. It is also flexible because you can add user-created and third-party controls to it.
There are three programming models you can use to create ASP.NET web applications. The other two, besides ASP.NET Web Forms, are ASP.NET MVC (Model, View, Controller) and ASP.NET Web Pages.
ASP.NET Web Forms applications execute on the server and generate output to the browser. They are written in a programming language that supports the .NET Common Language Runtime (CLR), such as C# or Visual Basic.
ASP.NET Web Forms server controls
The main building blocks of ASP .NET Web Forms pages are server controls. These are reusable components responsible for rendering HTML markup and responding to events. There are three kinds of server controls:
HTML server controls
Web server controls
Validation server controls
HTML server controls
HTML server controls are standard HTML controls, converted into a server control by adding the attribute runat=“server” and adding an id to make them available for server-side processing. The use of the id is to manipulate the HTML server control at runtime. For example, consider the HTML standard input control:
<input type = "text" size = "50">
It can be converted to a server control by adding the runat and id attributes:
<input type = "text" id = "servertext" size = "50" runat = "server">
Web server controls
Web server controls are a unique set of ASP.NET tags understood by the server. They are created on the server and require a runat=“server” attribute to work. However, Web server controls do not necessarily reflect HTML syntax.
Web server controls include form controls, such as radio buttons, text boxes, and checkboxes, as well as special-purpose controls, such as menus and calendars.
Using textbox control as an example, we can create a Web server control with the following syntax:
<asp : textbox text = "Edpresso Competition" id = "some_id" runat = "server"/>
Validation server controls
Validation server controls perform client-side validation, server-side validation, or both, depending on the browser capabilities that display the page.
The validation server control validates the values entered by users into other controls of the page. The user gets an error message whenever the user input does not pass validation.
The syntax for creating a validation server control is as follows:
<asp : control_name id = "some_id" runat = "server"/>
Components of ASP.NET Web Forms
ASP.NET Web Forms consist of three components.
The first is the ASP.NET framework, which consists of the Web Forms and the .NET Programming Language used to write the code behind the Web Forms.
The second is the server, which executes the Web Forms and generates the HTML markup that the browser can render.
The third is the browser, which displays the web page when requested by a user.
The diagram above is of IIS (Internet Information Server), one of the most popular Web servers created by Microsoft. It is used in hosting ASP Web applications and provides Internet-based services.