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Web-Based Applications

15. Web-Based Applications. C# Programming: From Problem Analysis to Program Design 3 rd Edition. Part II. Events. By default, only a few events trigger postback to the server Buttons click, events do

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Web-Based Applications

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  1. 15 Web-Based Applications C# Programming: From Problem Analysis to Program Design 3rd Edition C# Programming: From Problem Analysis to Program Design

  2. Part II C# Programming: From Problem Analysis to Program Design

  3. Events • By default, only a few events trigger postback to the server • Buttons click, events do • Changes in selections to ListBox, RadioButton, RadioButtonList, CheckBox, CheckBoxList, and DropDownList do not • AutoPostBack property can be set to true to automatically trigger a postback to the server • Be judicious with changes to AutoPostBack property C# Programming: From Problem Analysis to Program Design

  4. Adding Common Form-Type Controls Figure 15-19 Web site after adding server controls C# Programming: From Problem Analysis to Program Design

  5. Wiring Event-Handler Methods All three radio buttons wired to the same event-handler method Figure 15-20 Wiring the same event to three RadioButton objects C# Programming: From Problem Analysis to Program Design

  6. RadioButton Event-Handler Method privatevoid radioButton_CheckedChanged(object sender, System.EventArgs e) { if (this.radBtnFresSop.Checked) { this.lblClassif.Text = "Freshmen & Sophomores "; } elseif (this.radBtnJrSr.Checked) { // More statements C# Programming: From Problem Analysis to Program Design

  7. Button Event-Handler Method (continued) privatevoid btnSubmit_Click(object sender, System.EventArgs e) { this.lblSubmit.Text = "Thanks " + this.txtBxFname.Text + "! You will be contacted... "; if (lstBxInterests.SelectedIndex > -1) { this.lblSubmit.Text += " to discuss joining" + " the \"" + this.lstBxInterests.SelectedItem.Text + "\" team."; } } Retrieve from TextBox and selections from ListBox Retrieve values from TextBox and selections from ListBox C# Programming: From Problem Analysis to Program Design

  8. Validation, Custom, and Composite Controls C# Programming: From Problem Analysis to Program Design

  9. Validation Control Properties • Treat validation control objects like any other control • Properties • ControlToValidate • Tie the validation control to a specific form control object • ErrorMessage • Set to the message you want displayed when the input control does not pass the validation C# Programming: From Problem Analysis to Program Design

  10. Validation Controls (continued) RequiredField Validator control is placed beside the object it is validating Figure 15-21 Adding a RequiredFieldValidator control C# Programming: From Problem Analysis to Program Design

  11. Page Validation • Every control field on the page that has an associated validation control is checked when the page is posted • CausesValidation property of Button(s) can be set to false • By default, every Button object's CausesValidation property is set to true C# Programming: From Problem Analysis to Program Design

  12. Calendar Control • Display calendar months on a Web page • Calendar is live • Can view and select dates • Properties • SelectedDate • Used to pick the month, day, and year for display • Initially set to the current date; date can be set programmatically • Customize with gridlines, borders; change font, background, foreground colors; set cell padding and spacing C# Programming: From Problem Analysis to Program Design

  13. Calendar Control (continued) Click here to view “code behind” file Current selection (.aspx file) Use Page_Load( ) event-handler method to set the date with program statements Click here to view HTML tags Current design view Figure 15-23 Switching between .aspx and .aspx.cs files C# Programming: From Problem Analysis to Program Design

  14. Calendar Control (continued) Figure 15-24 Using the Properties window to set the SelectedDate property C# Programming: From Problem Analysis to Program Design

  15. DateTime Class C# Programming: From Problem Analysis to Program Design

  16. Using a Calendar Control in Applications privatevoid btnShowCalendar_Click(object sender, System.EventArgs e) { Calendar1.SelectedDates.Clear( ); meetingDate = new DateTime (DateTime.Today.Year, DateTime.Today.Month, DateTime.Today.Day, 8,0,0); meetingDate = meetingDate.AddDays(7); if (meetingDate.DayOfWeek.ToString() == "Sunday") { meetingDate = meetingDate.AddDays(1); } C# Programming: From Problem Analysis to Program Design

  17. Using a Calendar Control in Applications (continued) Calendar1.SelectedDate = meetingDate; this.lblMsg.Text = ("Meeting " + "next week: " +meetingDate.DayOfWeek + ", " + meetingDate.Month + "/" + meetingDate.Day + " at " + meetingDate.Hour + " P.M."); } // end of btnShowCalendar_Click ( ) method C# Programming: From Problem Analysis to Program Design

  18. Calendar Control (continued) Displayed date Figure 15-25 Calendar showing different dates selected C# Programming: From Problem Analysis to Program Design

  19. DataGrid and GridView Controls • Display data in a tabular format • Can bind data to a data source, such as a database • Common data source classes used to bind DataGrid objects to the actual data • DataReader • DataSet C# Programming: From Problem Analysis to Program Design

  20. GridView Control • GridView is a little more sophisticated than DataGrid • GridView features • Automatic data binding • Auto generation of buttons for selecting, editing, and deleting • Automatic sorting • Automatic paging C# Programming: From Problem Analysis to Program Design

  21. Using a DataGrid Control in Applications • Use OleDB Data Provider for Access database • Connection string identifies the provider as an Access database and specifies the name of the database • Follow same guidelines/steps used to connect to database using Windows application • Minor change needed for Web application • DataBind( ) method call is different for Web applications C# Programming: From Problem Analysis to Program Design

  22. WebControls Application– Database Access privatevoid btnShowMembers_Click(object sender, System.EventArgs e) { lblMembers.Visible = true; try { string sConnection = "Provider= Microsoft.ACE.OLEDB.12.0;" + "Data Source=" + "C:\\CSharpProjects\\WebControls\\member.accdb"; OleDbConnection dbConn = new OleDbConnection(sConnection); string sql = "Select FirstName, LastName From memberTable " + " Order By LastName Asc, FirstName Asc;"; C# Programming: From Problem Analysis to Program Design

  23. OleDbCommand dbCmd = new OleDbCommand( ); dbCmd.CommandText = sql; dbCmd.Connection = dbConn; OleDbDataAdapter memberDataAdap = new OleDbDataAdapter( ); memberDataAdap.SelectCommand = dbCmd; memberDS = new DataSet( ); // DataSet declared as protected class member memberDataAdap.Fill(memberDS, "memberTable"); // Binding is only change needed from the Windows app this.dataGrid1.DataBind( ); } // Catch clause goes here C# Programming: From Problem Analysis to Program Design

  24. AccessDataSource • Can use the data visual configuration tools and have these statements automatically generated for you • Instead of writing the program statements • AccessDataSource and SqlDataSource • These classes reduce the need for accessing individual Data Provider classes • All providers (SQL Server, Oracle, ODBC, and OLEDB) can use SqlDataSource. C# Programming: From Problem Analysis to Program Design

  25. AccessDataSource (continued) • AccessDataSource inherits from the SqlDataSource • Use SQL queries to perform data retrieval • Includes large number of properties and methods • Do not have to set the Connection String property • Just identify the location of the Access .mdb file using the DataFile property • Can provide relative path to the data base • Use visual configuration tools to connect C# Programming: From Problem Analysis to Program Design

  26. Using Visual Tools to Connect GridView object dragged to form New Data Source Smart tag Figure 15-26 Binding data source to the GridView C# Programming: From Problem Analysis to Program Design

  27. Use Visual Tools to Connect (continued) Figure 15-27 Connecting to Access database C# Programming: From Problem Analysis to Program Design

  28. Use Visual Tools to Connect (continued) Place database in the reserved App_Data directory Figure 15-28 Relative address for the Access database C# Programming: From Problem Analysis to Program Design

  29. Use Visual Tools to Connect (continued) Figure 15-29 AccessDataSource Object C# Programming: From Problem Analysis to Program Design

  30. Use Visual Tools to Connect (continued) Figure 15-30 Identify what data to retrieve C# Programming: From Problem Analysis to Program Design

  31. Modifying the Data • By default, DataGrid control displays data in read-only format • To allow users to edit data, use Advanced tab from the Data Source Configuration tool to configure the select statement • This generates the additional Insert, Delete, and Update SQL statements • All primary key values must be retrieved as part of the select statement • Key columns can be removed using the smart tag once the configuration is complete C# Programming: From Problem Analysis to Program Design

  32. Use Visual Tools to Connect (continued) Figure 15-31 GridView tasks C# Programming: From Problem Analysis to Program Design

  33. Use Visual Tools to Connect (continued) • When application runs, columns display Edit and Delete • Clicking the Edit button causes the row of data to be displayed in an editable format Figure 15-32 Modifying data table C# Programming: From Problem Analysis to Program Design

  34. Other Controls • Navigation • Can now add site navigation by defining a site map • TreeView and SiteMapPath controls • Data • DetailsView and FormView controls • Display and edit data from different data sources • Automatically retrieve data when page runs C# Programming: From Problem Analysis to Program Design

  35. Other Controls (continued) • Login • Security control that enables you to authenticate users • PasswordRecovery control helps users change or remember passwords • LoginStatus control lets you present a Login or Logout button C# Programming: From Problem Analysis to Program Design

  36. C# Programming: From Problem Analysis to Program Design

  37. C# Programming: From Problem Analysis to Program Design

  38. Web Services • Enable exchange of data from one computer to another,over the Internet or an intranet • Applications that return data • Do not involve presentation layer • Uses standard protocols • Hypertext Transfer Protocol (HTTP) • Extensible Markup Language (XML) • Simple Object Access Protocol (SOAP) • Web Services Description Language (WSDL) C# Programming: From Problem Analysis to Program Design

  39. Web Services (continued) • Messages are sent as XML from one method to another • Data is physically returned as part of an XML message • XML uses tags to provide format for describing data like HTML • HTML tags tell browser how to display data in different formats • XML is readable • XML uses tags to describe the data being exchanged C# Programming: From Problem Analysis to Program Design

  40. Windows Communication Foundation (WCF) • Used to build connected service-oriented applications Figure 15-34 WCF service application C# Programming: From Problem Analysis to Program Design

  41. Smart Device Applications (Optional) • Mobile application development involves writing apps for handheld devices • Many different platforms • Windows Mobile OS – compact Microsoft OS • Silverlight for Windows Phone • Windows Phone Developer Tools-CTP must be installed • Applications can be created without a PDA • Emulator that simulates device is included C# Programming: From Problem Analysis to Program Design

  42. Silverlight • Template for developing applications for smart devices targets Silverlight • Web application framework that enables you to integrate multimedia-like graphics, sounds, and animations into applications • Uses a subset of the framework • Graphical user interfaces are less sophisticated • Fewer controls and events C# Programming: From Problem Analysis to Program Design

  43. Silverlight (continued) • User interfaces that are declared in Extensible Application Markup Language (XAML) • XAML file contains a Canvas object, which acts asplaceholder for other elements C# Programming: From Problem Analysis to Program Design

  44. Creating a Smart Device Application • Select File, New, Project, Visual C#, Silverlight for Windows Phone • Select Windows Phone Application • Blank miniature phone is displayed with a left arrow, Windows logo, and a search tool • ContentGridis placed on the phone • Using the WYSIWYG approach, drag and drop controls to the form C# Programming: From Problem Analysis to Program Design

  45. Creating a Smart Device Application (continued) Figure 15-35 Adding controls to the smart device application C# Programming: From Problem Analysis to Program Design

  46. Create Smart Device Application (continued) Figure 15-36 Adding controls to the smart device application C# Programming: From Problem Analysis to Program Design

  47. Drag controls onto phone Set properties Use Format alignment tools Double-click on text to register event-handler methods Create Smart Device Application (continued) Figure 15-37 Metric/English Converter final design C# Programming: From Problem Analysis to Program Design

  48. Creating a Smart Device Application (continued) • Only programming statements added were those included in the event-handler methods privatevoid btnCompute_Click (object sender, System.EventArgs e) { this.lblResult.Text = (double.Parse(this.txtBxV1.Text)* double.Parse(this.txtBxV2.Text)).ToString( ); } private void menuExit_Click (object sender, System.EventArgs e) { this.Close( ); } C# Programming: From Problem Analysis to Program Design

  49. Click Start Without Debugging on the Debug Takes a couple minutes to load emulator Smart device app complete with Web browser Building and Running the Smart Device Application Figure 15-38 Phone emulator C# Programming: From Problem Analysis to Program Design

  50. Creating a Smart Device Application (continued) Figure 15-39 WinPhone App running Figure 15-40 Smart device application output C# Programming: From Problem Analysis to Program Design

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