Introductionto asp net-ppt
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This document provides an overview of ASP.NET development. It discusses key ASP.NET features such as Web Forms, Web Services, and the .NET Framework. It also covers ASP.NET concepts like the programming model with server-side controls and events, page lifecycle, view state, and maintaining state across postbacks. Common ASP.NET tasks like adding server code, using server controls, and handling page events are also explained at a high level.
Introductionto asp net-ppt
- 2. ASP.NET Overview Key Features Web Forms Web Services Built on .NET Framework Simple programming model Maintains page state Multibrowser support XCOPY deployment XML configuration Complete object model Session management Caching Debugging Extensibility Separation of code and UI Security ASPX, ASP side by side Simplified form validation Cookieless sessions
- 3. Common Language Specification Common Language Runtime VB C++ C# ASP.NET: Web Services and Web Forms JScript … Windows Forms Base Classes ADO.NET: Data and XML VisualStudio.NET ASP.NET Overview Architecture
- 6. Asp.NET ? Simply Server side language Simplified page development model Modular, well-factored, extensible architecture Superior debugging and tracing support Compiled, not interpreted Rich caching support Web farm scalable session state Automatically detects and recovers from errors
- 8. ASP.NET Execution Model First call to particular page
- 9. General Things to know Client Side Scripting Server Side Scripting HTML JavaScript CSS Jquery Ajax XML
- 10. Background ASP Successes Simple procedural programming model Access to COM components ActiveX Data Objects (ADO) File System Object Custom components Script-based: no compiling, just edit, save & run VBScript, JScript – leverages existing skills Support for multiple scripting languages ASP has been very popular
- 14. Programming Model Controls and Events Button List Text Browser ASP.NET Button code ... List code ... Text code ... Event handlers
- 15. Web Forms in .NET Separate Code & Design Rich Web Forms Drag & Drop Design Like WinForms
- 16. Understand the Web Form Page Directive Server side code Form Normal HTML Structure Server Controls
- 17. Example: Inline Code Method 17 <html> <asp:Button id="btn" runat="server"/> ... </html> <script Language="c#" runat="server"> private void btn_Click(object sender, System.EventArgs e) { ... } </script>
- 18. Background Demo: HelloWorld.asp <html> <head><title>HelloWorld.asp</title></head> <body> <form method=“post"> <input type="submit" id=button1 name=button1 value="Push Me" /> <% if (Request.Form("button1") <> "") then Response.Write("<p>Hello, the time is " & Now()) end if %> </form> </body> </html>
- 19. You must Know Post Back communicates back to the server View State state stored in a hidden field on the page transported to the client and back to the server, Is not stored on the server
- 20. ASP.NET States Session State allows the state of objects (serializable) to be stored for a single session (lifetime of the user’s browser or specific timeout) Application State allows the state of objects (serializable) to be stored for the application across different sessions.
- 21. Master Page Template to Other pages
- 22. Agenda Background ASP.NET Overview Programming Model Programming Basics Server Controls Data Binding Conclusion
- 23. Programming Model Controls and Events Server-side programming model Based on controls and events Just like Visual Basic Not “data in, HTML out” Higher level of abstraction than ASP Requires less code More modular, readable, and maintainable
- 24. Programming Model Controls and Events Button List Text Browser ASP.NET Button code ... List code ... Text code ... Event handlers
- 25. Page Life Cycle PreInit Init Init Complete Preload Load Control events Load Complete Pre Render Save State Complete Render Unload
- 26. Programming Model ASP.NET Object Model User code executes on the web server in page or control event handlers Controls are objects, available in server-side code Derived from System.Web.UI.Control The web page is an object too Derived from System.Web.UI.Page which is a descendant of System.Web.UI.Control A page can have methods, properties, etc.
- 27. Programming Model Postbacks A postback occurs when a page generates an HTML form whose values are posted back to the same page A common technique for handling form data In ASP and other server-side technologies the state of the page is lost upon postback... Unless you explicitly write code to maintain state This is tedious, bulky and error-prone
- 28. Programming Model Postbacks Maintain State By default, ASP.NET maintains the state of all server-side controls during a postback Can use method="post" or method="get" Server-side control objects are automatically populated during postback No state stored on server Works with all browsers
- 29. Programming Model Server-side Controls Multiple sources of controls Built-in 3rd party User-defined Controls range in complexity and power: button, text, drop down, calendar, data grid, ad rotator, validation Can be populated via data binding
- 30. Programming Model Automatic Browser Compatibility Controls can provide automatic browser compatibility Can target UpLevel or DownLevel browsers UpLevel browsers support additional functionality, such as JavaScript and DHTML DownLevel browsers support HTML 3.2
- 31. Programming Model Automatic Browser Compatibility Button code ... Menu code ... Text code ... Event handlers Button Menu Text IE 4 Button Menu Text Netscape Button Menu Text IE 5.5 Button Menu Text IE 6 ASP.NET Button Control Menu Control Text Control ...
- 32. Programming Model Code-behind pages Two styles of creating ASP.NET pages Controls and code in .aspx file Controls in .aspx file, code in code-behind page Supported in Visual Studio.NET Code-behind pages allow you to separate the user interface design from the code Allows programmers and designers to work independently <%@ Codebehind=“WebForm1.bas” Inherits=WebApplication1.WebForm1” %>
- 33. Programming Model Automatic Compilation Just edit the code and hit the page ASP.NET will automatically compile the code into an assembly Compiled code is cached in the CLR Assembly Cache Subsequent page hits use compiled assembly If the text of the page changes then the code is recompiled Works just like ASP: edit, save and run
- 34. Agenda Background ASP.NET Overview Programming Model Programming Basics Server Controls Data Binding Conclusion
- 35. Programming Basics Page Syntax The most basic page is just static text Any HTML page can be renamed .aspx Pages may contain: Directives: <%@ Page Language=“VB” %> Server controls: <asp:Button runat=“server”> Code blocks: <script runat=“server”>…</script> Data bind expressions: <%# %> Server side comments: <%-- --%> Render code: <%= %> and <% %> Use is discouraged; use <script runat=server> with code in event handlers instead
- 36. Programming Basics The Page Directive Lets you specify page-specific attributes, e.g. AspCompat: Compatibility with ASP Buffer: Controls page output buffering Codepage: Code page for this .aspx page Content Type: MIME type of the response ErrorPage: URL if unhandled error occurs Inherits: Base class of Page object Language: Programming language Trace: Enables tracing for this page Transaction: COM+ transaction setting Only one page directive per .aspx file
- 37. Programming Basics Server Control Syntax Controls are declared as HTML tags with runat=“server” attribute Tag identifies which type of control to create Control is implemented as an ASP.NET class The id attribute provides programmatic identifier It names the instance available during post back Just like Dynamic HTML <input type=text id=text2 runat=“server” /> <asp:calendar id=myCal runat=“server” />
- 38. Programming Basics Server Control Properties Tag attributes map to control properties c1.Text = “Foo” c2.Rows = 5 <asp:button id=“c1" Text="Foo" runat=“server”> <asp:ListBox id=“c2" Rows="5" runat=“server”> Tags and attributes are case-insensitive Control properties can be set programmatically
- 39. Programming Basics Maintaining State By default. controls maintain their state across multiple post back requests Implemented using a hidden HTML field: __VIEWSTATE Works for controls with input data (e.g. Textbox, Checkbox), non-input controls (e.g. Label, Data Grid), and hybrids (e.g. Dropdown List, ListBox) Can be disabled per control or entire page Set EnableViewState=“false” Lets you minimize size of __VIEWSTATE
- 40. Programming Basics Maintaining State Demo: MaintainingState.asp, MaintainingState.aspx
- 41. Programming Basics Server Code Blocks Server code lives in a script block marked runat=“server” Script blocks can contain Variables, methods, event handlers, properties They become members of a custom Page object <script language="C#" runat=server> <script language="VB" runat=server> <script language="JScript" runat=server>
- 42. Programming Basics Page Events Pages are structured using events Enables clean code organization Avoids the “Monster IF” statement Less complex than ASP pages Code can respond to page events e.g. Page_Load, Page_Unload Code can respond to control events Button1_Click Textbox1_Changed
- 43. Programming Basics Page Event Lifecycle Page_Load Page_Unload Textbox1_Changed Button1_Click Initialize Restore Control State Save Control State Render 1. Change Events 2. Action Events Page_Init Control Events Load Page Unload Page
- 44. Programming Basics Page Loading Page_Load fires at beginning of request after controls are initialized Input control values already populated protected sub Page Load(s as Object, e as EventArgs) Message.Text = "Howdy, World!" End sub
- 45. Programming Basics Page Loading Page Load fires on every request Use Page.IsPostBack to execute conditional logic If a Page/Control is maintaining state then need only initialize it when IsPostBack is falseprotected sub Page Load(s as Object, e as EventArgs) if (Page.IsPostBack) then else ' Executes only on initial page load Message.Text = "initial value" ' Rest of procedure executes on every request end sub
- 46. Programming Basics Server Control Events Change Events By default, these execute only on next action event E.g. OnTextChanged, OnCheckedChanged Change events fire in random order Action Events Cause an immediate postback to server E.g. OnClick Works with any browser No client script required, no applets, no ActiveX® Controls!
- 47. Programming Basics Wiring Up Control Events Control event handlers are identified on the tag Event handler code protected sub btn1_Click(s as Object, e as EventArgs) Message.Text = “Button1 clicked” end sub <asp:button onclick="btn1_click“ runat=server> <asp:textbox onchanged="text1_changed“ runat=server>
- 48. Programming Basics Event Arguments Events pass two arguments: The sender, declared as type object Usually the object representing the control that generated the event Allows you to use the same event handler for multiple controls Arguments, declared as type EventArgs Provides additional data specific to the event EventArgs itself contains no data; a class derived from EventArgs will be passed
- 49. Programming Basics Page Unloading Page_Unload fires after the page is rendered Don’t try to add to output Useful for logging and clean up protected sub Page Unload(s as Object, e as EventArgs) MyApp.LogPageComplete() end sub
- 50. Programming Basics Import Directive Adds code namespace reference to page Avoids having to fully qualify .NET types and class names Equivalent to the VB imports directive <%@ Import Namespace="System.Data" %> <%@ Import Namespace="System.Net" %> <%@ Import Namespace="System.IO" %>
- 51. Programming Basics Page Class The Page object is always available when handling server-side events Provides a large set of useful properties and methods, including: Application, Cache, Controls, EnableViewState, EnableViewStateMac, ErrorPage, IsPostBack, IsValid, Request, Response, Server, Session, Trace, User, Validators DataBind(), LoadControl(), MapPath(), Validate()
- 52. Agenda Background ASP.NET Overview Programming Model Programming Basics Server Controls Data Binding Conclusion
- 53. Server Controls ASP.NET ships with ~50 built-in controls Organized into logical families HTML controls Controls / properties map 1:1 with HTML Web controls Richer functionality More consistent object model
- 54. Server Controls HTML Controls Work well with existing HTML designers Properties map 1:1 with HTML table.bgcolor ="red" Can specify client-side event handlers Good when quickly converting existing pages Derived from System.Web.UI.HtmlControls.HtmlControl Supported controls have custom class, others derive from HtmlGenericControl
- 55. Server Controls HTML Controls Supported controls <a> <img> <form> <table> <tr> <td> <th> <select> <textarea> <button> <input type=text> <input type=file> <input type=submit> <input type=button> <input type=reset> <input type=hidden>
- 56. Server Controls HTML Controls Demo 1: HTMLControls1.aspx Basic page lifecycle with HTML Controls Demo 2: HTMLControls2.aspx More HTML Controls
- 57. Server Controls HTML Controls Can use controls two ways: Handle everything in action events (e.g. button click) Event code will read the values of other controls (e.g. text, check boxes, radio buttons, select lists) Handle change events as well as action events
- 58. Server Controls Web Controls Consistent object model Label1.BackColor = Color.Red Table.BackColor = Color.Blue Richer functionality E.g. AutoPostBack, additional methods Automatic uplevel/downlevel support E.g. validation controls Strongly-typed; no generic control Enables better compiler type checking
- 59. Server Controls Web Controls Web controls appear in HTML markup as namespaced tags Web controls have an asp: prefix <asp:button onclick="button1_click“ runat=server> <asp:textbox onchanged="text1_changed“ runat=server> Defined in the System.Web.UI.WebControls namespace This namespace is automatically mapped to the asp: prefix
- 60. Server Controls Web Controls Web Controls provide extensive properties to control display and format, e.g. Font BackColor, ForeColor BorderColor, BorderStyle, BorderWidth Style, CssClass Height, Width Visible, Enabled
- 61. Server Controls Web Controls Four types of Web Controls Intrinsic controls List controls Rich controls Validation controls
- 62. Server Controls Intrinsic Controls Correspond to HTML controls Supported controls <asp:button> <asp:imagebutton> <asp:linkbutton> <asp:hyperlink> <asp:textbox> <asp:checkbox> <asp:radiobutton> <asp:image> <asp:label> <asp:panel> <asp:table>
- 63. Server Controls Intrinisic Controls TextBox, ListControl, CheckBox and their subclasses don’t automatically do a postback when their controls are changed Specify AutoPostBack=true to make change events cause a postback
- 64. Server Controls List Controls Controls that handle repetition Supported controls <asp:dropdownlist> <asp:listbox> <asp:radiobuttonlist> <asp:checkboxlist> <asp:repeater> <asp:datalist> <asp:datagrid>
- 65. Server Controls List Controls Repeater, DataList and DataGrid controls Powerful, customizable list controls Expose templates for customization Can contain other controls Provide event bubbling through their OnItemCommand event More about these controls and templates later
- 66. Server Controls Checkbox List & RadioButtonList Provides a collection of check box or radio button controls Can be populated via data binding <asp:CheckBoxList id=Check1 runat="server"> <asp:ListItem>Item 1</asp:ListItem> <asp:ListItem>Item 2</asp:ListItem> <asp:ListItem>Item 3</asp:ListItem> <asp:ListItem>Item 4</asp:ListItem> <asp:ListItem>Item 5</asp:ListItem> </asp:CheckBoxList>
- 67. Server Controls Intrinisic & Simple List Controls Demo 1: WebControls1.aspx Assorted intrinsic and list controls Demo 2: WebControls2.aspx Same controls with AutoPostBack
- 68. Server Controls Rich Controls Custom controls with rich functionality Supported Controls <asp:calendar> <asp:adrotator> More will be added 3rd party controls are coming Demo: RichControls1.aspx
- 69. Server Controls Validation Controls Rich, declarative validation Validation declared separately from input control Extensible validation framework Supports validation on client and server Automatically detects uplevel clients Avoids roundtrips for uplevel clients Server-side validation is always done Prevents users from spoofing Web Forms
- 70. Server Controls Validation Controls <asp:RequiredFieldValidator> Ensures that a value is entered <asp:RangeValidator> Checks if value is within minimum and maximum values <asp:CompareValidator> Compares value against constant, another control or data type <asp:RegularExpressionValidator> Tests if value matches a predefined pattern <asp:CustomValidator> Lets you create custom client- or server-side validation function <asp:ValidationSummary> Displays list of validation errors in one place
- 71. Server Controls Validation Controls Validation controls are derived from System.Web.UI.WebControls.BaseValidator, which is derived from the Label control Validation controls contain text which is displayed only if validation fails Text property is displayed at control location ErrorMessage is displayed in summary
- 72. Server Controls Validation Controls Validation controls are associated with their target control using the ControlToValidate property Can create multiple validation controls with the same target control <asp:TextBox id=TextBox1 runat=server /> <asp:RequiredFieldValidator id="Req1" ControlToValidate="TextBox1" Text="Required Field" runat=server />
- 73. Server Controls Validation Controls Page.IsValid indicates if all validation controls on the page succeed void Submit_click(s as object, e as EventArgs) if (Page.IsValid) then Message.Text = "Page is valid!" end if end sub
- 74. Server Controls Validation Controls Display property controls layout Static: fixed layout, display won’t change if invalid Dynamic: dynamic layout None: no display; can still use Validation Summary and Page.IsValid Type property specifies expected data type: Currency, Date, Double, Integer, String
- 75. Server Controls Validation Controls Can force down-level option Only server-side validation <% @ Page Language="c#" ClientTarget="DownLevel" %>
- 76. Server Controls Validation Controls Demo: ValidationControls1.aspx Demonstrates each type of validation control
- 77. Agenda Background ASP.NET Overview Programming Model Programming Basics Server Controls Data Binding Conclusion
- 78. Data Binding How to Populate Server Controls? Specify the data in the control’s tags Not dynamic: can’t get data from a database Write code that uses the control’s object model This is okay if you need to populate a simple value or list, but quickly gets too complicated for populating sophisticated displays Data binding Create an object that holds the data (Dataset, Array, string, int, etc.) Associate that object with the control
- 79. Data Binding What Is It? Provides a single simple yet powerful way to populate Web Form controls with data Enables clean separation of code from UI Supports binding to any data source Properties, expressions, method calls Collections (Array, Hashtable, etc.) DataSet, DataTable, DataView, DataReader XML One way snapshot model Requires code to reapply to data model
- 80. Data Binding What Is It? Allows you to specify an expression When the DataBind method of the control is called, the expression is evaluated and bound DataBind for a single control (and sub controls) Page.DataBind binds all controls on a page Works for scalars, e.g. Label control Works for lists, e.g. DropDown control, ListBox control, etc. Enables the use of templates
- 81. Data Binding Scalar Expressions Data binding expression: <%# expression %> Expression is evaluated when DataBind() is called <asp: Label id=label1 Text=<%# “The result is “ & (1 + 2) & “, the time is “ & DateTime.Now.ToLongTimeString() %> runat="server" /> public sub Page Load(s as object, e as EventArgs) if (Page.IsPostBack) then else Page.DataBind() end if end sub
- 82. Data Binding Scalar Expressions Demo: DataBinding1.aspx Data binding to simple, scalar expressions
- 83. Data Binding Simple Lists Data binding a list creates a user interface element for each item in the list Each item contains text (displayed to user) and an optional value (not displayed) The simple list controls: <asp:ListBox> Single or multiple select <asp:DropDownList> <asp:RadioButtonList> <asp:CheckBoxList>
- 84. Data Binding Simple Lists Steps to data bind a list control Declare the list control Optionally set DataValueField and DataTextField Set its Data Source Call DataBind() method
- 85. Data Binding Simple Lists Demo: DataBinding2.aspx Data binding to simple lists
- 86. Resources General Sites http://msdn.microsoft.com/net/aspnet/default.asp http://www.asp.net/ http://www.fmexpense.com/quickstart/aspplus/defau lt.htm http://www.asptoday.com/ http://www.aspng.com/aspng/index.aspx http://www.4guysfromrolla.com/ http://www.aspfree.com/ http://www.devx.com/dotnet/ http://www.ibuyspy.com/
- 87. Starting ASP.NET Development Web Site Don’t use this, here for compatibility only Each page is dynamically loaded into memory Slow on first load after deployment No need to recompile for code change
- 88. Starting ASP.NET Development .. Web Application Recommended Compiles all pages into one DLL Faster on first load after deployment Must recompile whole site for code change
- 89. Web Project in Asp.net
- 90. Thank You!