asp.net

Contents of an ASP.NET Page (.aspx)

1. HTML Tags
2. Server Side Tags or ASP.NET Controls
1. Special tags provided from .NET Framework which are internally classes
2. They starts with asp:, mobile: etc.
3. All such controls have runat=”server” attribute
3. Directives
1. Provides instructions to the compiler
2. Use <%@ and %> delimiters

                                                              i.      Page directive

1.      <%@ Page Language=”C#” %>

                                                            ii.      Import directive

1.      <%@ Import Namespace=”System.Data” %>

4. Scriplet
1. Merging code of a .NET language into ASP.NET page
2. Use <% and %> delimiters

Example

 

       <%

           for (int i = 1; i <= 100; i++)

               Response.Write(i+"<br>");

          

  %>

5. Expessions
1. Use <%= and %> delimiters to show the values of the variables and some expressions

Example

<% int n = 5; %>

<h1>Square of <%=n %> is <%=n*n %></h1>

6. Intrinsic Objects or Built-in Objects
1. Ready made objects provided by ASP.NET

                                                              i.      Request

                                                            ii.      Response

                                                          iii.      Session

                                                          iv.      Server

                                                            v.      Application

                                                          vi.      ViewState

7. Client Side Scripts
1. Used for client/side dynamicity

                                                              i.      Java Script

                                                            ii.      VBScript

                                                          iii.      JScript

Example

    <script type="text/javascript">

        function square()

        {

            var num=parseInt(document.f.txtNum.value);

            alert("Square is "+num*num);

        }

    </script>

<form name="f" id="f">

    <div>

   

    Number

        <input id="txtNum" name="txtNum" type="text" /><input id="Button1"

            type="button" value="Square" onclick="square()" /></div>

    </form>

Working with ASP.NET Controls

Label control

-          Text

TextBox control

-          Text

-          AccessKey

-          TextMode

-          MaxLength

-          ReadOnly

Button control

-          to create a push button

o   Text

ImageButton control

-          To use an image as button

o   ImageUrl

LinkButton control

-          To use a hyperlink kind of button

o   Text

Image control

-          To place an image

o   ImageUrl

Hyperlink Control

-          to make the hyperlink as Text or Image

o   Text

o   ImageUrl

o   NavigateUrl

o   Target

o   ToolTip

Moving a control to fix position

à Select the control à Format à Position à Absolute

à Now use drag and drop

Adding images into a project

-          Select Viewà Solution Explorer à Project Properties à Add à New Folder à Give some name to the folder like images

-          Now select the folder and add existing images

Note: Use Panel control to make the container and group to controls.

Sample Program 1

Write a web form to create two label Number and Result. Now create two text boxes, one to input a number and other to output a number (readonly). Now create three different buttons as simple button, image button and link button to show Square, SquareRoot and CubeRoot of give number.

Use Hotkeys on controls (AccessKey)

Creating a GIF file

-          Use GIF Animator tool to animate the image and make the GIF file

Note: The pages create for web applications are called as Web Forms. A web form is a class inherited from Page class of System.Web.UI namespace.

DropDownList control

-          Allows to select only one item from many items

-          Use Items collection to add the items

-          Each item is an object of ListItem class

o   ListItem(string text, string value)

-          SelectedItem

o   Text

o   Value

Note: Use Page.IsPostBack property to check the post backs

Example

protected void Page_Load(object sender, EventArgs e)

        {

            if (!IsPostBack)

            {

                for (int i = 1950; i <= DateTime.Now.Year; i++)

                    DropDownList1.Items.Add(new ListItem(i.ToString()));

            }

        }