Creating a New Component or Control
by Mike Snell, Lars Powers
Microsoft Visual Studio 2015 Unleashed, Third Edition
- About This eBook
- Title Page
- Copyright Page
- Contents at a Glance
- Table of Contents
- About the Authors
- Dedication
- Acknowledgments
- We Want to Hear from You!
- Reader Services
- Introduction
- Part I: Introducing Visual Studio 2015
- Chapter 1. A Quick Tour of Visual Studio 2015
- Chapter 2. The Visual Studio IDE
- Chapter 3. The .NET Languages
- What’s New in C# 6.0 and VB 14
- Language Primer
- Language Features
- Infer a Variable’s Data Type Based on Assignment
- Create an Object and Initialize Its Values (Object Initializers)
- Define a Collection and Initialize Its Values
- Creating an Instance of a Nonexistent Class
- Add Methods to Existing Classes (Extension Methods)
- Add Business Logic to Generated Code (Partial Methods)
- Access and Query Data Using the .NET Languages
- Write Simple Unnamed Functions Within Your Code (Lambda Expressions)
- Splitting an Assembly Across Multiple Files
- Working with XML Directly Within Your Code (VB Only)
- Removing Unused Arguments from Event Handlers (VB Only)
- Creating an Automatically Implemented Property
- Dropping the Underscore in VB for Line Continuation
- Working with Dynamic Languages/Objects
- Covariance and Contravariance
- Asynchronous Programming
- The .NET Framework
- Summary
- Part II: An In-Depth Look at the IDE
- Chapter 4. Solutions and Projects
- Chapter 5. Browsers and Explorers
- Chapter 6. Introducing the Editors and Designers
- Part III: Working with the Visual Studio Tools
- Chapter 7. Working with Visual Studio’s Productivity Aids
- Chapter 8. Testing Code
- Chapter 9. Refactoring Code
- Chapter 10. Debugging Code
- Chapter 11. Deploying Code
- Chapter 12. Developing Applications in the Cloud with Windows Azure
- Chapter 13. Working with Databases
- Part IV: Extending Visual Studio
- Part V: Building Web Applications
- Chapter 17. Building Modern Websites with ASP.NET 5
- Chapter 18. Using JavaScript and Client-Side Frameworks
- Chapter 19. Building and Consuming Services with Web API and WCF
- Part VI: Building Windows Client Apps
- Chapter 20. Building Windows Forms Applications
- Chapter 21. Building WPF Applications
- Chapter 22. Developing Office Business Applications
- Part VII: Creating Mobile Apps
- Chapter 23. Developing Windows Store Applications
- Chapter 24. Creating Windows Phone Applications
- Chapter 25. Writing Cross-Platform Mobile Applications with Apache Cordova
- Index
- Code Snippets
Creating a New Component or Control
Starting from an existing WinForms project, you kick off the process of authoring a component by using the Add New Item dialog box (from the Project menu). Selecting Component Class in this dialog box adds the stub code file to your current project and launches the component designer. To start control development, you use the Add New User Control dialog box.
Note
Two different “types” of WinForms controls can be authored within Visual Studio: custom controls and user controls. Custom controls inherit directly from the System.Windows.Forms.Control class; they are typically code intensive because you, the developer, are responsible for writing all the code necessary to render the control’s visual portion. User controls (sometimes called composite controls) inherit from the System.Windows.Forms.UserControl class. User controls are advantageous because you can build them quickly by compositing other controls together that are already available in the Toolbox. These controls already have their user interface portion coded for you.
Both the control and the component designers work on the same principles as the Windows Forms Designer: The designers allow you to drag an object from the Toolbox onto the design surface.
Assume that you need a component that sends a signal across a serial port every x minutes. Because Visual Studio already provides a timer and a serial port component, which are accessible from the Toolbox, you can use the component designer to add these objects to your own custom component and then leverage and access their intrinsic properties and methods (essentially, using them as building blocks to get your desired functionality).
Figure 6.50 shows the component designer for this fictional custom component. Two objects have been added: a process component and a timer component.
A similar scenario can be envisioned with a user control. You can take the example of a login “form,” consisting of two text boxes, two labels, and two buttons, and actually make that a control (one that can be easily included in the Toolbox and dropped onto a Windows form or web form).
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