Windows Workflow Foundation (WF) lần đầu tiên được giới thiệu vào năm 2006 với NET Nó có lẽ là công bằng để nói rằng WF không nhận được chấp nhận phổ biến Microsoft đã hy vọng. Điều này thiếu sự hấp thu được có thể là do một số yếu tố | CHAPTER 6 Windows Workflow Foundation 4 Availability Framework Windows Workflow Foundation WF was first introduced in 2006 with .NET . It is probably fair to say that WF didn t receive the widespread adoption Microsoft was hoping for. This lack of uptake was probably due to a number of factors Although the WF designer offers a natural way of working it is a very different way of developing applications and contains a new API to master. Slow performance. Writing your own work flow activities was not as easy as it could be. Handling and passing data between activities was cumbersome Limited support for messaging scenarios and integration with WCF. Some developers were confused by the hosting model. A clunky designer interface made you want to poke your own eyes out OK it wasn t that bad but it wasn t that good either . Microsoft has aimed to address these issues and also to integrate WCF and WF closer than ever before. Why Use WF Before we look at how to use Microsoft WF you may be wondering why should I bother WF can greatly simplify the development of applications that deal with complex and long-running Processes as traditional coding methods are not ideal for solving this type of problem. To understand why they are not let s take the example of a visa approval system loosely based on my experience of the UK Australian emigration process as shown in the flowchart in Figure 6-1. 127 CHAPTER 6 WINDOWS WORKFLOW FOUNDATION 4 Figure 6-1. Visa processing system workflow 128 CHAPTER 6 WINDOWS WORKFLOW FOUNDATION 4 Even if you have no experience of the Australian emigration process you can probably gain an understanding from Figure 6-1. Windows Workflow enables you to design and develop your application in a similar visual manner. Consider how an application to handle such a process would be coded it would probably be difficult to gain an understanding at a glance. Figure 6-2 shows a possible WF implementation of the process. As you can see it s not so different .
