Windows programming architecture with sample program

Some common services include the Spooler service which controls printing, the Server service which supports file, print and named-pipe sharing over the network and the DHCP client service which registers and updates IP addresses and DNS records. Now, let's take a look at Programs, Processes and Threads. One of our Escalation Engineers uses a very simple analogy for explaining the difference between these three terms:. Think of a process as a room and a thread as a person in the room.

A program is a set of instructions for the person in the room to carry out. For the purpose I need some guidance regarding how to create architecture for the application and which pattern to use. Also I heard MVVM is the best approach for windows application so how to encorporate that in windows application?

Also we are planning not to use wpf for the 1st release, so how to make it flexible enough to accommodate the further changes if we plan to use wpf? I am completely new to windows application development so a sample may do a worth. Wednesday, July 13, PM. Also you may use 3 tier architecture. These layers are described below.

Application layer or Business layer. The main characteristic of a Host Architecture is that the application and databases reside on the same host computer and the user interacts with the host using an unfriendly and dump terminal. This architecture does not support distributed computing the host applications are not able to connect a database of a strategically allied partner. Some managers found that developing a host application take too long and it is expensive.

Consequently led these disadvantages to Client-Server architecture. Client-Server architecture is 2-Tier architecture because the client does not distinguish between Presentation layer and business layer. The Client-Server Architecture is also a burden to network traffic and resources.

Let us assume that about five hundred clients are working on a data server then we will have five hundred ODBC connections and several ruffian record sets, which must be transported from the server to the clients because the Business layer is stayed in the client side.

Figure 1: A simple Windows programming model. Window Procedure. A window procedure is a function that receives and processes all messages sent to the window. Every window class has a window procedure, and every window created with that class uses that same window procedure to respond to messages. The system sends a message to a window procedure by passing the message data as arguments to the procedure.

The window procedure then performs an appropriate action for the message; it checks the message identifier ID and, while processing the message, uses the information specified by the message parameters. A window procedure does not usually ignore a message. If it does not process a message, it must send the message back to the system for default processing. The window procedure does this by calling the DefWindowProc function, which performs a default action and returns a message result.

The window procedure must then return this value as its own message result. Most window procedures process just a few messages and pass the others on to the system by calling DefWindowProc. Because a window procedure is shared by all windows belonging to the same class, it can process messages for several different windows.

To identify the specific window affected by the message, a window procedure can examine the window handle passed with a message. The window procedure typically calls other functions to help process the messages it receives. It can call functions local to the application, or it can call API functions provided by Windows. The Win32 API includes hundreds of functions that an application can call to perform various tasks such as creating a window, drawing a line, and performing file input and output.

In C, the window procedure is typically implemented as a monolithic function containing a large switch statement with cases for individual messages. The code provided to process a particular message is known as a message handler. Windows defines hundreds of different message types.

These messages can be classified in various ways, but for the moment classification is not nearly as important as realizing the critical role messages play in the operation of an application. The following table shows 10 of the most common messages. One way to characterize a Windows program is to think of it as a collection of message handlers. To a large extent, it is a program's unique way of responding to messages that gives it its personality.

Common Windows Messages. Sent When. A character is input from the keyboard. The user selects an item from a menu, or a control sends a notification to its parent. A window is created. A window is destroyed.

The left mouse button is pressed. The left mouse button is released. The mouse pointer is moved. A window needs repainting. The application is about to terminate. A window is resized. Table 1: Windows messages example. A message manifests itself in the form of a call to a window's window procedure. Bundled with the call are four input parameters:. The handle of the window to which the message is directed,.

A message ID, and. Two bit parameters known as wParam and lParam. The window handle is a bit value that uniquely identifies a window. Internally, the value references a data structure in which Windows stores relevant information about the window such as its size, style, and location on the screen. A large portion of programming for the Windows environment involves message handling.

Each time an event such as a keystroke or mouse click occurs, a message is sent to the application, which must then handle the event. The Microsoft Foundation Class Library offers a programming model optimized for message-based programming.

In this model, " message maps " are used to designate which functions will handle various messages for a particular class. In all cases, the design programming fits within a larger context of planning efforts which can also be programmed.

For design programming for a building, we propose a six-step process as follows:. This step is necessary if the programmer is working on a project type for the first time. The programmer should become familiar with some of the following relevant information:. Working with the committee, the programmer solicits and suggests broad goal statements that will guide the remainder of the programming process. Each of the following categories of goals should be addressed:.

Based upon the goals, the categories of relevant information can be determined and researched. Typical categories include:. Programmatic strategies suggest a way to accomplish the goals given what one now knows about the opportunities and constraints. A familiar example of a programmatic strategy is the relationship or "bubble" diagram. These diagrams indicate what functions should be near each other in order for the project to function smoothly. Relationship diagrams can also indicate the desired circulation connections between spaces, what spaces require security or audio privacy, or other aspects of special relationships.

Other types of strategies recur in programs for many different types of projects. Some examples of common categories of programmatic strategies include:. Ideally, each of the goals and objectives identified in Step 2 will have some sort of strategy for addressing that goal.

Otherwise, either the goal is not very important, or more discussion is required to address how to achieve that goal or objective. Cost, schedule, and affordable area are interdependent. Costs are affected by inflation through time. Affordable area is determined by available budgets. In this step, one must reconcile the available budget with the amount of improvements desired within the project time frame. First, a list of spaces is developed to accommodate all of the activities desired see Exhibit A.

The space criteria researched in Step 3 are the basis of this list of space requirements. The space requirements are listed as net assignable square feet NASF , referring to the space assigned to an activity, not including circulation to that space. A percentage for "tare" space is added to the total NASF. Tare space is the area needed for circulation, walls, mechanical, electrical and telephone equipment, wall thickness, and public toilets.