© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved. 1 Outline 5.1 Test-Driving the Inventory Application 5.2 Introduction to C# Code 5.3 Inserting an Event Handler 5.4 Performing a Calculation and Displaying the Result 5.5 Using the Debugger: Syntax Errors 5.6 Wrap-Up Tutorial 5 – Completing the Inventory Application Introducing Programming

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved. 2 Objectives In this tutorial, you will learn to: –Add an event handler for a Button control. –Insert code into an event handler. –Access a property’s value by using C# code. –Use the assignment and multiplication operators.

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Test-Driving the Inventory Application

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Test-Driving the Inventory Application Input data into application –Enter 3 in the Cartons per shipment: TextBox –Enter 15 in the Items per carton: TextBox Figure 5.1 Inventory application with quantities entered.

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Test-Driving the Inventory Application Click the Calculate Total Button –Observe result of calculation in the descriptive Label Figure 5.2 Result of clicking the Calculate Total Button in the Inventory application. Result of calculation

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code The Options dialog –Setting option for Visual Studio.NET environment

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Figure 5.3 Options dialog. Text Editor folder icon

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Adding line numbers –Select the Text Editor folder icon Select the General item –Place a check in the CheckBox next to Line Numbers

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Figure 5.4 General settings page for C# text editor. C# folder General item Line Numbers CheckBox (checked)

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Setting the tab –Change the Indenting option –Change the Tabs settings –Insert spaces for each tab

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Figure 5.5 Setting the Tabs options. Smart Indenting (selected) Tabs item Insert spaces (selected)

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Fonts and colors –Change color used to display code –Use Defaults Button resets values

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Figure 5.6 Examining the Fonts and Colors page. Fonts and Colors item Use Defaults Button

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Renaming the Form –Set Form ’s Name property to FrmInventory

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code The code editor –Code view using directive –Allows access to classes within specified namespace Class declaration –class keyword –Identifier –Braces around class body –Case sensitivity C# keywords and identifiers are case sensitive –Main method

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Figure 5.7 IDE showing the uppermost portion of the code for the Inventory application. Inventory.cs tabbed window Class declaration Class is declared in the Inventory namespace Using FCL namespaces

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Figure 5.8 IDE showing the lowermost portion of the code for the Inventory application. Main method

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Generated code –Expanding the code –Outlined code

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Figure 5.9 Windows Form Designer generated code, when expanded. Expanded code

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Figure 5.10 Ellipses indicating outlined code. Outlined code

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Generated code for a control –Default properties –The result of changes from design view

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Introduction to C# Code Figure 5.11 Code generated by the IDE for lblCartons (with the code setting the Text property highlighted). Click tab for design view Property values for lblCartons

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler Renaming the Form in code –In comments above class declaration –In Main method

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler Figure 5.12 Renaming the Form above the class declaration.

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler Figure 5.13 Renaming the Form in method Main and adding spacing.

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler Event handling –Visual Studio.NET automatically inserts event handler when controls are double clicked –Event handler naming convention

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler Figure 5.14 Event handler btnCalculate_Click before you add your code. Asterisks indicate unsaved changes to application Empty event handler

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler Examine the application –Closing an application using the close box Figure 5.15 Running application without functionality. Close box

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler Adding code to an event handler –Comments in code Comments appear in green Use double slash characters –Executable C# statement Ends with semicolon Accessing properties –Member access operator (. )

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler Figure 5.16 Adding code to the Calculate Total Button ’s event handler. Event handler Type this code

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler IntelliSense –Display entire class’ members and their purposes Assignment operator –Two operands –Right to left

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler Figure 5.17 IntelliSense activating while entering code. Selected member Intellisense Description of selected member

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Inserting an Event Handler Run the application –Enter input and examine the result Figure 5.18 Running the application with an event handler. Result of clicking Calculate Total Button

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Performing a Calculation and Displaying the Result Changing the event handler –Add comments –Break header over multiple lines –Multiplication operator Int32.Parse method –Call a method –Return a value Convert.ToString method

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Performing a Calculation and Displaying the Result Figure 5.19 Using multiplication in the Inventory application. Modified Inventory application code

Outline © Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved. 36 Inventory.cs (1 of 4) Renaming the Form

Outline © Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved. 37 Inventory.cs (2 of 4)

Outline © Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved. 38 Inventory.cs (3 of 4) Renaming the Form Adding a comment to your code Adding an event handler to your code Adding a comment to your code

Outline © Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved. 39 Inventory.cs (4 of 4) Adding a comment to your code

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Using the Debugger: Syntax Errors Output window –Shows result of compilation Figure 5.21 Results of successful build in the Output window.

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Using the Debugger: Syntax Errors The Task List –Displays the build error Description of the error Line number corresponding to the error Figure 5.22 Task List lists syntax errors.

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Using the Debugger: Syntax Errors Identifying syntax error –Real-time error checking –Errors are underlined by a red jagged line –Task List will display the errors

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Using the Debugger: Syntax Errors Figure 5.23 IDE with syntax errors. Jagged red underline indicates syntax error

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Using the Debugger: Syntax Errors Figure 5.24 Task List displaying the syntax error recognized in real time.

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Using the Debugger: Syntax Errors Matching the syntax error in the code –Double click an error in the Task List to highlight the code with the syntax error

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Using the Debugger: Syntax Errors Figure 5.25 Highlighting the portion of code where a syntax error occurs. Highlighted syntax error

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Using the Debugger: Syntax Errors Identifying second syntax error –Build > Build Solution compiles code Syntax error not found in real time

© Copyright by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved Using the Debugger: Syntax Errors Figure 5.26 IDE with second syntax error. Jagged blue underline indicates compilation error Compilation error shown in task list