1. 21
ASP.NET 2.0, Web Forms and
Web Controls

2. A fair question should be followed by a deed in silence.
If any man will draw up his case, and put his name at the foot of the first page, I will give him an immediate reply. Where he compels me to turn over the sheet, he must wait my leisure.
Lord Sandwich
Rule One: Our client is always right Rule Two: If you think our client is wrong, see Rule One.
Anonymous
A fair question should be followed by a deed in silence.
Dante Alighieri

3. You will come here and get books that will open your eyes, and your ears, and your curiosity, and turn you inside out or outside in.
Ralph Waldo Emerson

4. OBJECTIVES In this chapter you will learn:
Web application development using ASP.NET.
To create Web Forms.
To create ASP.NET applications consisting of multiple Web Forms.
To maintain state information about a user with session tracking and cookies.
To use the Web Site Administration Tool to modify Web application configuration settings.
To control user access to Web applications using forms authentication and ASP.NET login controls.
To use databases in ASP.NET applications.
To design a master page and content pages to create a uniform look-and-feel for a Web site.

5. 21.1 Introduction
21.2 Simple HTTP Transactions
21.3 Multitier Application Architecture
21.4 Creating and Running a Simple Web-Form Example
Examining an ASPX File
Examining a Code-Behind File
Relationship Between an ASPX File and a Code- Behind File
How the Code in an ASP.NET Web Page Executes
Examining the XHTML Generated by an ASP.NET Application
Building an ASP.NET Web Application
21.5 Web Controls
Text and Graphics Controls
AdRotator Control
Validation Controls

6. 21.6 Session Tracking
Cookies
Session Tracking with HttpSessionState
21.7 Case Study: Connecting to a Database in ASP.NET
Building a Web Form That Displays Data from a Database
Modifying the Code-Behind File for the Guestbook Application
21.8 Case Study: Secure Books Database Application
Examining the Completed Secure Books Database Application
Creating the Secure Books Database Application
21.9 Wrap-Up
21.10 Web Resources

7. Fig. 21. 1 | Client interacting with Web server
Fig | Client interacting with Web server. Step 1: The GET request.

8. Fig. 21. 2 | Client interacting with Web server
Fig | Client interacting with Web server. Step 2: The HTTP response.

9. Fig. 21.3 | Three-tier architecture.

10. Outline
WebTime.aspx

11. Portability Tip 21.1
The same Web control can map to different XHTML elements, depending on the client browser and the Web control’s property settings.

12. Outline
WebTime.aspx.cs
(1 of 2)

13. Outline
WebTime.aspx.cs
(2 of 2)

14. Performance Tip 21.1
Once an instance of the Web page has been created, multiple clients can use it to access the page—no recompilation is necessary. The project will be recompiled only when you modify the application; changes are detected by the runtime environment, and the project is recompiled to reflect the altered content.

15. Outline
WebTime.html

16. Fig. 21.7 | Creating an ASP.NET Web Site in Visual Web Developer.

17. Fig. 21.8 | Solution Explorer window for project WebTime.
Code-behind file
Properties
Refresh
Nest Related Files
View Code
View Designer
Copy Web Site
ASP.NET Configuration
ASPX file
Fig | Solution Explorer window for project WebTime.

18. Fig. 21.9 | Toolbox in Visual Web Developer.

19. Fig. 21.10 | Source mode of the Web Forms Designer.
Design mode button
Source mode button
Fig | Source mode of the Web Forms Designer.

20. Fig. 21.11 | Design mode of the Web Forms Designer.
Cursor
Cursor’s current location
Fig | Design mode of the Web Forms Designer.

21. Fig. 21. 12 | Code-behind file for Default
Fig | Code-behind file for Default.aspx generated by Visual Web Developer.

22. Portability Tip 21.2
Absolute positioning is discouraged, because pages designed in this manner may not render correctly on computers with different screen resolutions and font sizes. This could cause absolutely positioned elements to overlap each other or display off-screen, requiring the client to scroll to see the full page content.

23. Fig. 21.13 | WebTime.aspx after inserting text and a new paragraph.
Cursor position after inserting text and a new paragraph by pressing Enter
Block Format drop-down list
Fig | WebTime.aspx after inserting text and a new paragraph.

24. Label
Fig | WebTime.aspx after adding a Label and setting its properties.

25. Fig. 21.15 | Commonly used Web controls.

26. Outline
WebControls.aspx
(1 of 6)

27. Outline
WebControls.aspx
(2 of 6)

28. Outline
WebControls.aspx
(3 of 6)

29. Outline
WebControls.aspx
(4 of 6)

30. Outline
WebControls.aspx
(5 of 6)

31. Outline (6 of 6) WebControls.aspx Image control TextBox control
DropDownList control
HyperLink control
RadioButtonList control
Button control
WebControls.aspx
(6 of 6)

32. Fig. 21.17 | DropDownList Tasks smart tag menu.

33. Outline
FlagRotator.aspx
(1 of 2)

34. Outline (2 of 2) FlagRotator.aspx (a) (b) AdRotator image
AlternativeText displayed in a tooltip
(b)
(c)
FlagRotator.aspx
(2 of 2)

35. Outline
AdRotator Information.xml
(1 of 4)

36. Outline
AdRotator Information.xml
(2 of 4)

37. Outline
AdRotator Information.xml
(3 of 4)

38. Outline
AdRotator Information.xml
(4 of 4)

39. Outline
Validation.aspx
(1 of 6)

40. Outline
Validation.aspx
(2 of 6)

41. Outline
Validation.aspx
(3 of 6)

42. Outline
Validation.aspx
(4 of 6)

43. Outline
(a)
(b)
Validation.aspx
(5 of 6)

44. Outline
(c)
(d)
Validation.aspx
(6 of 6)

45. Outline
Validation.aspx.cs
(1 of 2)

46. Outline
Validation.aspx.cs
(2 of 2)

47. Performance Tip 21.2
Setting EnableViewState to False reduces the amount of data passed to the Web server with each request.

48. Outline
Validation.html
(1 of 9)

49. Outline
Validation.html
(2 of 9)

50. Outline
Validation.html
(3 of 9)

51. Outline
Validation.html
(4 of 9)

52. Outline
Validation.html
(5 of 9)

53. Outline
Validation.html
(6 of 9)

54. Outline
Validation.html
(7 of 9)

55. Outline
Validation.html
(8 of 9)

56. Outline
Validation.html
(9 of 9)

57. Portability Tip 21.3
Clients may disable cookies in their Web browsers to ensure that their privacy is protected. Such clients will experience difficulty using Web applications that depend on cookies to maintain state information.

58. Outline
Options.aspx
(1 of 4)

59. Outline
Options.aspx
(2 of 4)

60. Outline
(a)
Options.aspx
(3 of 4)
(b)

61. Outline
(c)
Options.aspx
(4 of 4)
(d)

62. Outline
Options.aspx.cs
(1 of 3)

63. Outline
Options.aspx.cs
(2 of 3)

64. Outline
Options.aspx.cs
(3 of 3)

65. Outline
Recommendations .aspx
(1 of 2)

66. Outline
Recommendations .aspx
(2 of 2)

67. Outline
Recommendations .aspx.cs
(1 of 2)

68. Outline
Recommendations .aspx.cs
(2 of 2)

69. Fig. 21.27 | HttpCookie properties.

70. Outline
Options.aspx
(1 of 4)

71. Outline
Options.aspx
(2 of 4)

72. Outline
(a)
Options.aspx
(3 of 4)
(b)

73. Outline
(c)
Options.aspx
(4 of 4)
(d)

74. Software Engineering Observation 21.1
A Web Form should not use instance variables to maintain client state information, because each new request or postback, is handled by a new instance of the page. Web Forms should maintain client state information in HttpSessionState objects, because such objects are specific to each client.

75. Outline
Options.aspx.cs
(1 of 3)

76. Outline
Options.aspx.cs
(2 of 3)

77. Outline
Options.aspx.cs
(3 of 3)

78. Software Engineering Observation 21.2
One of the primary benefits of using HttpSessionState objects (rather than cookies) is that HttpSessionState objects can store any type of object (not just Strings) as attribute values. This provides you with increased flexibility in determining the type of state information to maintain for clients.

79. Fig. 21.30 | HttpSessionState properties.

80. Outline
Recommendations .aspx
(1 of 2)

81. Outline
Recommendations .aspx
(2 of 2)

82. Outline
Recommendations .aspx.cs
(1 of 2)

83. Outline
Recommendations .aspx.cs
(2 of 2)

84. Fig. 21.33 | Guestbook application GUI in Design mode.
GridView control
Fig | Guestbook application GUI in Design mode.

85. Fig. 21.34 | Change Data Source dialog in Visual Web Developer.

86. Fig. 21.35 | Configuring the SELECT statement used by the SqlDataSource to retrieve data.

87. Fig. 21.36 | Previewing the data retrieved by the SqlDataSource.

88. SqlDataSource control
Fig | Design mode displaying SqlDataSource control for a GridView.

89. Fig. 21.38 | Removing the MessageID column from the GridView.

90. Fig. 21.39 | Setting up INSERT parameters based on control values.

91. Outline
Guestbook.aspx
(1 of 7)

92. Outline
Guestbook.aspx
(2 of 7)

93. Outline
Guestbook.aspx
(3 of 7)

94. Outline
Guestbook.aspx
(4 of 7)

95. Outline
Guestbook.aspx
(5 of 7)

96. Outline
(a)
Guestbook.aspx
(6 of 7)

97. Outline
(b)
Guestbook.aspx
(7 of 7)

98. Outline
Guestbook.aspx.cs
(1 of 2)

99. Outline
Guestbook.aspx.cs
(2 of 2)

100. Fig. 21.42 | Login.aspx page of the secure books database application.

101. Fig. 21.43 | CreateNewUser.aspx page of the secure book database application.

102. Fig. 21.44 | Message displayed to indicate that a user account was created successfully.

103. Fig. 21.45 | Books.aspx displaying books by Harvey Deitel (by default).

104. Fig. 21.46 | Books.aspx displaying books by Andrew Goldberg.

105. Fig. 21.47 | Logging in using the Login control.

106. Fig. 21.48 | Error message displayed for an unsuccessful login attempt using the Login control.

107. Fig. 21.49 | Web Site Administration Tool for configuring a Web application.

108. Fig. 21.50 | Security page of the Web Site Administration Tool.

109. Fig. 21. 51 | Choosing the type of authentication used by an ASP
Fig | Choosing the type of authentication used by an ASP.NET Web application.

110. Fig. 21.52 | Main page of the Web Site Administration Tool after enabling forms authentication.

111. Fig. 21.53 | Add New Access Rule page used to configure directory access.

112. Fig. 21.54 | Master page in Source mode.

113. Fig. 21.55 | Master page in Design mode.

114. Outline
Bug2Bug.master
(1 of 2)

115. Outline
Bug2Bug.master
(2 of 2)

116. Fig. 21.57 | Content page CreateNewUser.aspx in Source mode.

117. Fig. 21.58 | Content page CreateNewUser.aspx in Design mode.

118. Outline
CreateNewUser.aspx
(1 of 3)

119. Outline
CreateNewUser.aspx
(2 of 3)
(a)
(b)

120. Outline
(c)
CreateNewUser.aspx
(3 of 3)

121. Outline
Login.aspx
(1 of 2)

122. Outline
(a)
(b)
Login.aspx
(2 of 2)

123. Fig. 21.61 | Authors DataTable in the Dataset Designer.

124. Fig. 21.62 | Query Builder for designing a query that selects books written by a particular author.

125. Fig. 21.63 | Dataset Designer after adding the TitlesTableAdapter.

126. Fig. 21.64 | Choosing a business object for an ObjectDataSource.

127. Fig. 21.65 | Choosing a data method of a business object for use with an ObjectDataSource.

128. Fig. 21.66 | Choosing a data source for a DropDownList.

129. Fig. 21.67 | Choosing the data source for a parameter in a business object’s data method.

130. Fig. 21.68 | Completed Books.aspx in Design mode.

131. Outline
Books.aspx
(1 of 5)

132. Outline
Books.aspx
(2 of 5)

133. Outline
(a)
Books.aspx
(3 of 5)

134. Outline
(b)
Books.aspx
(4 of 5)

135. Outline
(c)
Books.aspx
(5 of 5)