ClickOnce Deployment In .NET Framework 2.0

It is very common among the developers of previous generations to choose web applications over rich Windows UIs because of the deployment challenges associated with deploying a Smart Client Windows Forms application. However with the release of Visual Studio 2005, Microsoft has released a new technology named ClickOnce that is designed to solve the deployment issues for a windows forms application. This new technology not only provides an easy application installation mechanism but also enables easy deployment of upgrades to existing applications.

Since the introduction of the powerful server side web technologies such as ASP, JSP, ASP.NET, developers have shown more interest in building web applications rather than in windows applications. The factors that attracted the developers toward web applications can be summarized as follows:

• A web application is ubiquitous, making it accessible in all the places where an internet connection is available.

• The second and most important factor is the deployment. With web applications, there is no need to deploy any software on the client side. All the client application needs is just the browser. This makes it possible for the developers to easily deploy updates to the existing web application without impacting the client machines.

If you talk to the developers, you will find that the main reason for preference for web applications over windows applications is the second point in the above list. Even though this is true with traditional applications, Microsoft is making every attempt to ensuring that windows applications can be deployed and updated with the same ease as the web applications.

You can see proofs of this in the initial release of .NET Framework when Microsoft introduced the deployment of windows forms application through HTTP. Using this approach, you could simply use HREF HTML element to point to a managed executable (.exe). Then when you click on the HREF link, Internet Explorer can automatically download and install the executable on the client machine. Even though this approach sounds very promising, it also presents some interesting challenges.

One of the most important challenges is the downloading of the updated code through the HTTP. Since this process was not transacted, it was possible for the application to be left in an inconsistent state.

Moreover there was no way for you to specify if the application could work in offline mode apart from the traditional online mode. Combined with the operational mode issue, this approach also did not provide the ability to create shortcuts that can be used to launch the application. Even though this approach presented itself with a lot of issues, it could still be used in controlled environments.

However for complex multi-assembly dependant windows forms applications, you needed a transacted and easily updateable way of deployment. This is exactly what the ClickOnce technology introduced with .NET Framework 2.0 provides.

2D Graphics Techniques

2D graphics models may combine geometric models (also called vector graphics), digital images (also called raster graphics), text to be typeset (defined by content, font style and size, color, position, and orientation), mathematical functions and equations, and more. These components can be modified and manipulated by two-dimensional geometric transformations such as translation, rotation, scaling.

In object-oriented graphics, the image is described indirectly by an object endowed with a self-rendering method—a procedure which assigns colors to the image pixels by an arbitrary algorithm. Complex models can be built by combining simpler objects, in the paradigms of object-oriented programming.

Direct painting

A convenient way to create a complex image is to start with a blank "canvas" raster map (an array of pixels, also known as a bitmap) filled with some uniform background color and then "draw", "paint" or "paste" simple patches of color onto it, in an appropriate order. In particular, the canvas may be the frame buffer for a computer display.
Some programs will set the pixel colors directly, but most will rely on some 2D graphics library and/or the machine's graphics card, which usually implement the following operations

• paste a given image at a specified offset onto the canvas;


• write a string of characters with a specified font, at a given position and angle;


• paint a simple geometric shape, such as a triangle defined by three corners or ,a circle with given center and radius;


• draw a line segment, arc, or simple curve with a virtual pen of given width.

Extended color models

Text, shapes and lines are rendered with a client-specified color. Many libraries and cards provide color gradients, which are handy for the generation of smoothly-varying backgrounds, shadow effects, etc.. (See also Gouraud shading). The pixel colors can also be taken from a texture, e.g. a digital image (thus emulating rub-on screentones and the fabled "checker paint" which used to be available only in cartoons).

Painting a pixel with a given color usually replaces its previous color. However, many systems support painting with transparent and translucent colors, which only modify the previous pixel values. The two colors may also be combined in fancier ways, e.g. by computing their bitwise exclusive or. This technique is known as inverting color or color inversion, and is often used in graphical user interfaces for highlighting, rubber-band drawing, and other volatile painting—since re-painting the same shapes with the same color will restore the original pixel values.

Layers

The models used in 2D computer graphics usually do not provide for three-dimensional shapes, or three-dimensional optical phenomena such as lighting, shadows, reflection, refraction, etc.. However, they usually can model multiple layers (conceptually of ink, paper, or film; opaque, translucent, or transparent—stacked in a specific order. The ordering is usually defined by a single number (the layer's depth, or distance from the viewer).

Layered models are sometimes called 2 1/2-D computer graphics. They make it possible to mimic traditional drafting and printing techniques based on film and paper, such as cutting and pasting; and allow the user to edit any layer without affecting the others. For these reasons, they are used in most graphics editors. Layered models also allow better anti-aliasing of complex drawings and provide a sound model for certain techniques such as mitered joints and the even-odd rule.

Layered models are also used to allow the user to suppress unwanted information when viewing or printing a document, e.g. roads and/or railways from a map, certain process layers from an integrated circuit diagram, or hand annotations from a business letter.

In a layer-based model, the target image is produced by "painting" or "pasting" each layer, in order of decreasing depth, on the virtual canvas. Conceptually, each layer is first rendered on its own, yielding a digital image with the desired resolution which is then painted over the canvas, pixel by pixel. Fully transparent parts of a layer need not be rendered, of course. The rendering and painting may be done in parallel, i.e. each layer pixel may be painted on the canvas as soon as it is produced by the rendering procedure.

Layers that consist of complex geometric objects (such as text or polylines) may be broken down into simpler elements (characters or line segments, respectively), which are then painted as separate layers, in some order. However, this solution may create undesirable aliasing artifacts wherever two elements overlap the same pixel.

2D Computer Graphics

2D computer graphics is the computer-based generation of digital images—mostly from two-dimensional models (such as 2D geometric models, text, and digital images) and by techniques specific to them. The word may stand for the branch of computer science that comprises such techniques, or for the models themselves.


Raster graphic sprites and masks 2D computer graphics are mainly used in applications that were originally developed upon traditional printing and drawing technologies, such as typography, cartography, technical drawing, advertising, etc.. In those applications, the two-dimensional image is not just a representation of a real-world object, but an independent artifact with added semantic value; two-dimensional models are therefore preferred, because they give more direct control of the image than 3D computer graphics (whose approach is more akin to photography than to typography).


In many domains, such as desktop publishing, engineering, and business, a description of a document based on 2D computer graphics techniques can be much smaller than the corresponding digital image—often by a factor of 1/1000 or more. This representation is also more flexible since it can be rendered at different resolutions to suit different output devices. For these reasons, documents and illustrations are often stored or transmitted as 2D graphic files.


2D computer graphics started in the 1950s, based on vector graphics devices. These were largely supplanted by raster-based devices in the following decades. The PostScript language and the X Window System protocol were landmark developments in the field.

Subfields Of Computer Graphics

Geometry

Geometry studies the representation of three-dimensional objects in a discrete digital setting. Because the appearance of an object depends largely on the exterior of the object, boundary representations are most common in computer graphics. Two dimensional surfaces are a good analogy for the objects most often used in graphics, though quite often these objects are non-manifold. Since surfaces are not finite, a discrete digital approximation is required: polygonal meshes (and to a lesser extent subdivision surfaces) are by far the most common representation, although point-based representations have been gaining some popularity in recent years. These representations are Lagrangian, meaning the spatial locations of the samples are independent. In recent years, however, Eulerian surface descriptions (i.e., where spatial samples are fixed) such as level sets have been developed into a useful representation for deforming surfaces which undergo many topological changes (with fluids being the most notable example).

Subfields Of Geometry

• Constructive solid geometry - Process by which complicated objects are modelled with implicit geometric objects and boolean operations.

• Discrete differential geometry - a nascent field which defines geometric quantities for the discrete surfaces used in computer graphics.

• Digital geometry processing - surface reconstruction, simplification, fairing, mesh repair, parameterization, remeshing, mesh generation, surface compression, and surface editing all fall under this heading.

• Point-based graphics - a recent field which focuses on points as the fundamental representation of surfaces.

• Subdivision surfaces Out-of-core mesh processing - another recent field which focuses on mesh datasets that do not fit in main memory.

Animation

Animation studies descriptions for surfaces (and other phenomena) that move or deform over time. Historically most interest in this area has been focused on parametric and data-driven models, but in recent years physical simulation has experienced a renaissance due to the growing computational capacity of modern machines.

Subfields Of Animation

• Performance capture
• Character animation
• Physical simulation (e.g. cloth modeling, animation of fluid dynamics, etc.)

Rendering

Rendering converts a model into an image either by simulating light transport to get physically-based photorealistic images, or by applying some kind of style as in non-photorealistic rendering. The two basic operations in realistic rendering are:

• Transport (how much light gets from one place to another) and
• Scattering (how surfaces interact with light).

Transport

Transport describes how illumination in a scene gets from one place to another. Visibility is a major component of light transport.

Scattering

Models of scattering and shading are used to describe the appearance of a surface. Although these issues may seem like problems all on their own, they are studied almost exclusively within the context of rendering.
Shading can be broken down into two orthogonal issues, which are often studied independently:

• Scattering : How light interacts with the surface at a given point.
• Shading : How material properties vary across the surface.

The former problem refers to scattering, i.e., the relationship between incoming and outgoing illumination at a given point. Descriptions of scattering are usually given in terms of a bidirectional scattering distribution function or BSDF. The latter issue addresses how different types of scattering are distributed across the surface (i.e., which scattering function applies where). Descriptions of this kind are typically expressed with a program called a shader. (Note that there is some confusion since the word "shader" is sometimes used for programs that describe local geometric variation.)

Other subfields

• Physically-based rendering - concerned with generating images according to the laws of geometric optics.
• Real time rendering - focuses on rendering for interactive applications, typically using specialized hardware like GPUs.
• Non-photorealistic rendering
• Relighting - recent area concerned with quickly re-rendering scenes.

Computer Graphics

Computer graphics is a sub-field of computer science and is concerned with digitally synthesizing and manipulating visual content. Although the term often refers to three-dimensional computer graphics, it also encompasses two-dimensional graphics and
image processing.


Definition

Computer graphics broadly studies the manipulation of visual and geometric information using computational techniques. Computer graphics as an academic discipline focuses on the mathematical and computational foundations of image generation and processing rather than purely aesthetic issues.

Major subfields in computer graphics might be:

1. Geometry: studies ways to represent and process surfaces.
2. Animation: studies with ways to represent and manipulate motion.
3. Rendering: studies algorithms to reproduce light transport.
4. Imaging: studies image acquisition or image editing.

Types Of Operating System

Generally,there are four Types of Operating System:

Real-time Operating System:

A real-time operating system (RTOS) is an operating system that guarantees a certain capability within a specified time constraint. For example, an operating system might be designed to ensure that a certain object was available for a robot on an assembly line. In what is usually called a "hard" real-time operating system, if the calculation could not be performed for making the object available at the designated time, the operating system would terminate with a failure. In a "soft" real-time operating system, the assembly line would continue to function but the production output might be lower as objects failed to appear at their designated time, causing the robot to be temporarily unproductive.

In general, real-time operating systems are said to require:

• Multitasking
• Process threads that can be prioritized.
• A sufficient number of interrupt levels.

Real-time operating systems are often required in small embedded operating systems that are packaged as part of microdevices. Some kernels can be considered to meet the requirements of a real-time operating system. However, since other components, such as device drivers, are also usually needed for a particular solution, a real-time operating system is usually larger than just the kernel.

Single-user, single-tasking operating system:

As the name implies, this operating system is designed to manage the computer so that one user can effectively do one thing at a time. The Palm O.S. for Palm handheld computers is a good example of a modern single-user, single-task operating system.

Single-user, multi-tasking operating system:

This is the type of operating system most people use on there desktop and laptop computers today. Windows 98 and the Mac O.S. are both examples of an operating system that will let a single user has several programs in operation at the same time. For example, it's entirely possible for a Windows user to be writing a note in a word processor while downloading a file from the Internet while printing the text of an e-mail message.

Multi-user operating systems:

A multi-user operating system allows many different users to take advantage of the computer's resources simultaneously. The operating system must make sure that the requirements of the various users are balanced, and that each of the programs they are using has sufficient and separate resources so that a problem with one user doesn't affect the entire community of users. Unix, VMS, and mainframe operating systems, such as MVS, are examples of multi-user operating systems. It's important to differentiate here between multi-user operating systems and single-user operating systems that support networking. Windows 2000 and Novell Netware can each support hundreds or thousands of networked users, but the operating systems themselves aren't true multi-user operating systems. The system administrator is the only user for Windows 2000 or Netware. The network support and the entire remote user logins the network enables are, in the overall plan of the operating system, a program being run by the administrative user.

Functions of Operating System

In any computer, The Operating System will perform the following funtions:

• Controls the backing store and peripherals such as disk drives and printers.

• Controls the loading and running of programs.

• Organises the use of memory between programs.

• Organises processing time between programs and users.

• Organises priorities between program and users.

• Maintains security and access rights of users.

• Deals with errors and user instructions.

On a personal computer the operating system will:

• Deal with the transfer of programs in and out of memory.

• Allow the user to save files to a backing store.

• Control the transfer of data to peripherals such as printers.

• Provide the interface between user and computer - for example, Windows XP and OSX.

In a larger computer such as a main frame the operating system works on the same principles.

Technical Approach for Migrating VB 6.0 Application to VB .NET

If you upgrade a Visual Basic 6.0 project group or an n-tier application to Visual Basic .NET, you must upgrade one project or tier at a time.

If your three-tier application includes a client component, a business component, and a data access component, you should upgrade the application in the following order:

1. Client component, Business component, Data access component
2. Business component, Data access component
3. Data access component

In an n-tier application, always upgrade the client tier first, and then upgrade other tiers on the dependency tree. You should follow this order for two reasons:

• This approach allows you to keep the application working. When you upgrade the client, you break and work with only one component of the application. All of the other components continue to work the same way that they did previously. With this approach, you isolate the work area. Alternately, if you upgrade the data tier first, suddenly you break the data tier and the components that depend on the data tier.

• Visual Basic 6.0 locks type libraries (TypeLibs). This creates a problem if you need to rebuild the TypeLib or recompile the underlying dynamic-link library (DLL). If you upgrade the business tier first and then upgrade the client, you must continually stop and restart Visual Basic 6.0 every time you change the middle tier. Consider the following workflow:

1. Upgrade the middle tier. Change the Visual Basic 6.0 client to access the middle tier. Run the middle tier.
2. Change the Visual Basic 6.0 client to access the middle tier. Run the middle tier.
3. Run the middle tier.

If you want to change the .NET DLL, you must then close Visual Basic 6.0, recompile in .NET, restart Visual Basic 6.0, and so on. You can avoid this problem if you upgrade the client first and then upgrade the middle tier.

To upgrade each Visual Basic 6.0 application, use the Upgrade tool that is included with Visual Basic .NET. The Upgrade tool is started when you use Visual Basic .NET to open a Visual Basic 6.0 project. When you use the Upgrade tool, the Visual Basic 6.0 project is not changed, and a new Visual Basic .NET project is created. Before you upgrade a Visual Basic 6.0 project, it is best to prepare it for upgrade.

Migration Strategy for Upgrading VB 6.0 Application to VB .NET

When we start developing any new software solution, certain steps are taken. We begin with a plan, identify processes, gather requirements, and eventually build the architecture of the solution. Once things start taking shape, we start with development. Why do we choose this path? We all know that the path for doing the analysis and design up front has been proven to save a lot of time and cost for software development. In order to migrate projects from any prior version of Visual Basic, the path for analysis and design up front yields the best results.

The analysis part is slightly different in this case. We begin by studying the current application, and try to identify code blocks that require changes. In order to migrate your VB applications, it is not recommended that you directly convert your existing applications to .NET and fix the converted code in .NET. It is always better to take the existing application to the "Migration Ready" stage.

Here are the steps for migrating applications from VB 6.0 to VB .NET:

1. Evaluate the project and create a migration strategy.
2. Make the changes in VB 6.0 project and create a "Migration Strategy."
3. Migrate using the Visual Basic .NET Migration tool.
4. If the changes are not at par, make more changes and use the Migration tool (repeat Steps 2 and 3 as necessary).
5. Get developers at speed and make changes in .NET.
6. Build the .NET solution.

Migrating Applications from VB 6.0 to VB .NET

Introduction

Microsoft Visual Basic has had many evolutions since its original release, Visual Basic 1.0. The release of Visual Basic .NET is the biggest evolution yet. The language has been redesigned to take advantage of the .NET Framework. By leveraging the features that the .NET Framework provides, Visual Basic supports language features such as code inheritance, visual forms inheritance, and multi-threading. The object model is more extensive than earlier versions, and Visual Basic .NET totally integrates with the .NET Framework. Therefore, interaction between components written in other .NET languages is very efficient.

Benefits Reaped:

• Visual Basic .NET is the next version of Visual Basic. Rather than simply adding some new features to Visual Basic 6.0, Microsoft has reengineered the product to make it easier than ever before to write distributed applications such as Web and enterprise n-tier systems. Visual Basic .NET has two new forms packages (Windows Forms and Web Forms); a new version of ADO for accessing disconnected data sources; and streamlined language, removing legacy keywords, improving type safety, and exposing low-level constructs that advanced developers require.

• These new features open new doors for the Visual Basic developer: With Web Forms and ADO .NET, you now can rapidly develop scalable Web sites; with inheritance, the language now truly supports object-oriented programming; Windows Forms natively supports accessibility and visual inheritance; and deploying your applications is now as simple as copying your executables and components from directory to directory.

• Visual Basic .NET is now fully integrated with the other Microsoft Visual Studio .NET languages. Not only can you develop application components in different programming languages, your classes also can now inherit from classes written in other languages using cross-language inheritance. With the unified debugger, you can now debug multiple language applications, irrespective of whether they are running locally or on remote computers. Finally, whatever language you use, the Microsoft .NET Framework provides a rich set of APIs for Microsoft Windows® and the Internet.

• There were two options to consider when designing Visual Basic .NET—retrofit the existing code base to run on top of the .NET Framework, or build from the ground up, taking full advantage of the platform. To deliver the features most requested by customers (for example, inheritance and threading), to provide full and uninhibited access to the platform, and to ensure that Visual Basic moves forward into the next generation of Web applications, the right decision was to build from the ground up on the new platform. For example, many of the new features found in Windows Forms could have been added to the existing code base as new controls or more properties. However, this would have been at the cost of all the other great features inherent to Windows Forms, such as security and visual inheritance.

• One of Microsoft's major goals was to ensure Visual Basic code could fully interoperate with code written in other languages, such as Microsoft Visual C# or Microsoft Visual C++, and enable the Visual Basic developer to harness the power of the .NET Framework simply, without resorting to the programming workarounds traditionally required to make Windows APIs work. Visual Basic now has the same variable types, arrays, user-defined types, classes, and interfaces as Visual C++ and any other language that targets the Common Language Runtime; however, we had to remove some features, such as fixed-length strings and non-zero based arrays from the language.

• Visual Basic is now a true object-oriented language; some unintuitive and inconsistent features such as GoSub/Return and DefInt have been removed from the language.

• The result is a re-energized Visual Basic, which will continue to be the most productive tool for creating Windows-based applications, and is now positioned to be the best tool for creating the next-generation Web sites.