Vb.net session 10

  • 310 views
Uploaded on

 

More in: Technology
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
310
On Slideshare
0
From Embeds
0
Number of Embeds
1

Actions

Shares
Downloads
0
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Introducing User Controls And ManagingComponentsPre-Assessment Questions • Consider the following statements: • Statement A: Timer is an in-built component. • Statement B: ServiceController is an in-built components. Which of the following is correct with respect to the above statements? d. Both, Statement A and Statement B, are False. e. Both, Statement A and Statement B, are True. f. Statement A is True and Statement B is False. g. Statement A is False and Statement B is True. ©NIIT Creating and Managing components Lesson 1B / Slide 1 of 27
  • 2. Introducing User Controls And ManagingComponentsPre-Assessment Questions (Contd.) • Consider the following statements: • Statement A. The wrapper that allows interaction between COM and .NET is called RCW. • Statement B. Implementation of component is called ActiveX. Which of the following is correct with respect to the above statements? d. Both, Statement A and Statement B, are False. e. Both, Statement A and Statement B, are True. f. Statement A is True and Statement B is False. g. Statement A is False and Statement B is True ©NIIT Creating and Managing components Lesson 1B / Slide 2 of 27
  • 3. Introducing User Controls And ManagingComponentsPre-Assessment Questions (Contd.) 1. The assemblies that are required during the execution of an assembly are called: • Metadata • Portable executable • Manifest • Dependencies 3. Using COM+, the business logic can be placed in: • First tier • Middle tier • Third tier • Any tier ©NIIT Creating and Managing components Lesson 1B / Slide 3 of 27
  • 4. Introducing User Controls And ManagingComponentsPre-Assessment Questions (Contd.) • Consider the following statements: • Statement A. Friend constructor can be used if you want to use a component inside an assembly but not outside it. • Statement B. Private constructor can be used in a component if you want to use it outside the component class. Which of the following is correct with respect to the above statements? d. Both, Statement A and Statement B, are False. e. Both, Statement A and Statement B, are True. f. Statement A is True and Statement B is False. g. Statement A is False and Statement B is True. ©NIIT Creating and Managing components Lesson 1B / Slide 4 of 27
  • 5. Introducing User Controls And ManagingComponentsSolutions to Pre-AssessmentQuestions 1. b. 2. b. 3. d. Dependencies 4. d. Any tier 5. c. ©NIIT Creating and Managing components Lesson 1B / Slide 5 of 27
  • 6. Introducing User Controls And ManagingComponentsObjectives In this lesson, you will learn to: • Create customized user controls • Add existing components and controls to a user control • Declare and raise events in a user control • Create a user control • Identify the need for Web services • Identify the enabling technologies in Web services • Add and remove Web references ©NIIT Creating and Managing components Lesson 1B / Slide 6 of 27
  • 7. Introducing User Controls And ManagingComponentsUnderstanding User Controls • In Visual Basic .NET, you use controls such as list boxes, text boxes, menus, check boxes, and buttons to add user interaction capability to the graphical applications. • These controls are visual components that can be used across applications. ©NIIT Creating and Managing components Lesson 1B / Slide 7 of 27
  • 8. Introducing User Controls And ManagingComponentsUser Controls • You can create composite reusable controls and selectively expose the properties of these controls. • The UserControl class can be used to combine the functionality of different controls into one unit that can be reused. • The UserControl class can contain multiple child controls. • The UserControl class presents a single and unified interface. ©NIIT Creating and Managing components Lesson 1B / Slide 8 of 27
  • 9. Introducing User Controls And ManagingComponentsCustomized User Controls • While creating a user control the class inherits from the UserControl class by default. • To inherit the user control from another existing control, the Inherits System.Windows.Forms. UserControl statement needs to be changed to the class from which you want to inherit the control. ©NIIT Creating and Managing components Lesson 1B / Slide 9 of 27
  • 10. Introducing User Controls And ManagingComponentsAdding Properties And Functions • To add functionalities to a control, code has to be added for the property by viewing the code for the control. • The code will consist of the get and set methods of the property. ©NIIT Creating and Managing components Lesson 1B / Slide 10 of 27
  • 11. Introducing User Controls And ManagingComponentsTesting a Control • A control is always used in a container. • To test a control, you must host it in a Windows Form. ©NIIT Creating and Managing components Lesson 1B / Slide 11 of 27
  • 12. Introducing User Controls And ManagingComponentsCreating Custom Controls from theControl Class • To build a control from scratch, you can inherit from the Control class. • The Control class defines input from the mouse and the keyboard. • The Control class also defines the bounds and size of controls. ©NIIT Creating and Managing components Lesson 1B / Slide 12 of 27
  • 13. Introducing User Controls And ManagingComponentsInheriting from a User Control • User control can be used to build other controls. • Parent methods of the base class can be overridden to provide extended functionality in the inherited control. ©NIIT Creating and Managing components Lesson 1B / Slide 13 of 27
  • 14. Introducing User Controls And ManagingComponentsRendering Graphical Interface ofCustom Controls • To provide a graphical interface to your custom controls you need to override the OnPaint() method of the control class. • The OnPaint() method is executed when a control is first drawn and when a control is resized. ©NIIT Creating and Managing components Lesson 1B / Slide 14 of 27
  • 15. Introducing User Controls And ManagingComponentsRaising Events • To use event handling, you should be able to: • Declare events. • Raise events. • handle the events raised by your control. ©NIIT Creating and Managing components Lesson 1B / Slide 15 of 27
  • 16. Introducing User Controls And ManagingComponentsDeclaring Events • You can declare events within: • Classes. • Structures. • Interfaces. • To declare an event, you need to use the Event keyword. • In Visual Basic .NET, you need to use the RaiseEvent keyword to raise an event. • Any object capable of raising an event is an event sender. • Event handlers are special types of procedures that are called when an event occurs. ©NIIT Creating and Managing components Lesson 1B / Slide 16 of 27
  • 17. Introducing User Controls And ManagingComponentsDelegates • In Visual Basic .NET, you use delegates to call event procedures. • Delegates are objects that you use to call the methods of other objects. • Delegates in Visual Basic .NET can reference both shared and instance methods. ©NIIT Creating and Managing components Lesson 1B / Slide 17 of 27
  • 18. Introducing User Controls And ManagingComponentsDelegates and AddressOf Operator • The AddressOf operator implicitly creates an instance of a delegate. • Event handlers can be removed dynamically by using the RemoveHandler keyword. ©NIIT Creating and Managing components Lesson 1B / Slide 18 of 27
  • 19. Introducing User Controls And ManagingComponents Demo Creating a User Control ©NIIT Creating and Managing components Lesson 1B / Slide 19 of 27
  • 20. Introducing User Controls And ManagingComponentsProblem Statement • Build a user Control named ‘MyClock’ that will display the current time and will also perform the function of an alarm. Test this user control in a VB.NET application. ©NIIT Creating and Managing components Lesson 1B / Slide 20 of 27
  • 21. Introducing User Controls And ManagingComponentsSolution • To build and use the ‘MyClock’ user control in an application, you need to perform the following steps: 1. Create the User Control. 2. Add Windows Controls to the User Controls. 3. Create the Inherited Control. 4. Add Properties to the User Control. 5. Test the User Control. ©NIIT Creating and Managing components Lesson 1B / Slide 21 of 27
  • 22. Introducing User Controls And ManagingComponentsUnderstanding Web Services • The evolution of the Internet has resulted in a gradual shift from desktop to distributed applications. • The development of distributed applications involves ensuring that components hosted in heterogeneous environments are interoperable. • To address these issues, Web Services have been introduced. ©NIIT Creating and Managing components Lesson 1B / Slide 22 of 27
  • 23. Introducing User Controls And ManagingComponentsIntroduction to Web Services • A Web service exposes a number of methods that provide functionality that can be used by one or more applications, regardless of the programming languages, operating systems, and hardware platforms used to develop them. • The methods that provide such functionality are called Web methods. • An application that uses a Web service is called a Web service client. ©NIIT Creating and Managing components Lesson 1B / Slide 23 of 27
  • 24. Introducing User Controls And ManagingComponentsEnabling Technologies used in WebServices • Enabling technologies used in Web Services are: • XML • XML is a plain-text format that can be understood by any platform. • SOAP • SOAP is a standard communication protocol for interchanging information in a structured format in a distributed environment. • WSDL • WSDL is a markup language that describes a Web service. • UDDI • UDDI provides a standard mechanism to register and discover a Web service. ©NIIT Creating and Managing components Lesson 1B / Slide 24 of 27
  • 25. Introducing User Controls And ManagingComponentsAdding and Removing Web referencesfrom a Project • A Web Reference can be added and removed by using Solution Explorer. • A Web Service can be called programmatically. ©NIIT Creating and Managing components Lesson 1B / Slide 25 of 27
  • 26. Introducing User Controls And ManagingComponentsSummary In this lesson, you learned that: • User controls are visual components. • You can create a reusable unit of controls and selectively expose their properties by inheriting from the UserControl class. • You can create a customized user control by inheriting from an existing control. • You can override the OnPaint() method to customize the drawing of a control. • You can declare, raise, and handle events. • Delegates are objects that you use to call the methods of other objects. ©NIIT Creating and Managing components Lesson 1B / Slide 26 of 27
  • 27. Introducing User Controls And ManagingComponentsSummary (Contd.) • A Web service exposes functionality that can be used by one or more applications, regardless of the programming languages, operating systems, and hardware platforms used to develop them. • The functionality exposed by a Web service can be accessed by applications by using Internet standards, such as HyperText Transfer Protocol (HTTP) and eXtensible Markup Language (XML). • To be able to communicate with each other, a Web service and a client application must agree upon a common protocol. SOAP is a standard communications protocol for interchanging information in a structured format in a distributed environment. • To be able to use a Web service, the developers of a client application need to know the methods exposed by the Web service and the parameters to be passed to these methods. Web Services Description Language (WSDL) is a markup language, which is used to describe a Web service. • The Universal Description Discovery and Integration (UDDI) initiative is used to allow client applications to discover the Web services provided by various Web service providers. ©NIIT Creating and Managing components Lesson 1B / Slide 27 of 27