This way, the server becomes aware of the overall application state and operates in a two-tiered connected way. NET component model provides various building blocks of ASP. Basically it is an object model, which describes: All ASP. These lists can be loaded either by code or by the List Item Collection editor.
NET controls are implemented as classes, and they have events which are fired when a user performs a certain action on them. Basic syntax of list box control: The List Item Collection object is a collection of List Item objects.
NET server controls allow calling client side code written using Java Script or VBScript. NET server controls use client side scripting to provide response to the users without posting back to the server. Apart from these scripts, the Button control has a property On Client Click, which allows executing client-side script, when the button is clicked.
The browser submits a web form to the web server and the server returns a full markup page or HTML page in response. The label shows page load, page initialization and, the page pre-render events. The methods and properties of the Http Server Utility class are exposed through the intrinsic Server object provided by ASP. The following table provides a list of the properties: The request object is an instance of the System. The information presented by this object is wrapped by the higher level abstractions (the web control model). However, the Http Response object still provides some important functionalities, like the cookie feature and the Redirect() method. Redirect() method allows transferring the user to another page, inside as well as outside the application. The following table provides some noteworthy properties of the Response object: The following simple example has a text box control where the user can enter name, a button to send the information to the server, and a label control to display the URL of the client computer. A Tree view control comes under navigation controls. task allows you to format the tree view as shown: Add a label control and a text box control on the page and name them lblmessage and txtmessage respectively. To create a group of radio buttons, you specify the same name for the Group Name attribute of each radio button in the group.
It consists of a large number of controls such as text boxes, buttons, and labels for assembling, configuring, and manipulating code to create HTML pages. NET web forms extend the event-driven model of interaction to the web applications. The Http Server Utility class provides numerous properties and methods to perform various jobs. It represents the values and properties of the HTTP request that makes the page loading into the browser. NET, the response object does not play any vital role in sending HTML text to the client, because the server-side controls have nested, object oriented methods for rendering themselves. The following table shows the inherited properties, common to all server controls: Let us look at a particular server control - a tree view control. Edit each of the nodes using the Tree view node editor as shown: Once you have created the nodes, it looks like the following in design view: The Auto Format... A check box displays a single option that the user can either check or uncheck and radio buttons present a group of options from which the user can select just one option.
Only HTTP cannot keep track of all the information coming from various pages. NET session state and server side infrastructure keeps track of the information collected globally over a session. NET runtime carries the page state to and from the server across page requests while generating ASP. NET server controls with a visual aspect are derived from the Web Control class and inherit all the properties, events, and methods of this class. Basic syntax of check box: These control let a user choose from one or more items from the list.
NET runtime codes, and incorporates the state of the server side components in hidden fields. The Web Control class itself and some other server controls that are not visually rendered are derived from the System. List boxes and drop-down lists contain one or more list items.
When the button is clicked, the Button_Click event is raised and that also sends a message to be displayed on the label. These settings describe how the web forms (.aspx) or user controls (.ascx) pages are processed by the . The syntax for declaring a directive is: In this section, we will just introduce the ASP.
Create a new website and drag a label control and a button control on it from the control tool box. Set the Text property of the Button control as 'Click'. NET directives and we will use most of these directives throughout the tutorials. The basic syntax of Application directive is: The Assembly directive links an assembly to the page or the application at parse time.
The default event handler could be created in Visual Studio, just by double clicking the control in design view. A check box list presents a list of independent options.
The following table shows some of the default events for common controls: This example includes a simple page with a label control and a button control on it. These controls contain a collection of List Item objects that could be referred to through the Items property of the control.
This clause names the control and event that the procedure handles. Some events are not posted back to the server immediately, these are called non-postback events. The nonpostback events could be made to post back immediately by setting their Auto Post Back property to true. The List Item Collection Editor is used to add item to a drop-down list or list box. To display the collection editor, select edit item from the smart tag menu, or select the control and then click the ellipsis button from the Item property in the properties window.
The ASP tag for a button control: Some events cause the form to be posted back to the server immediately, these are called the postback events. For example, the change events or selection events such as Text Box. The default event for the Page object is Load event. For example, default event for the button control is the Click event. Common properties of List Item Collection: A radio button list presents a list of mutually exclusive options.
Consider the simple page: tags contain the hidden fields which store the view state and validation information. NET provides three types of button control: Text box controls are typically used to accept input from the user.