tailieunhanh - windows vista for developers delivery guide phần 7

Các thông tin trong một ràng buộc có thể phức tạp, và một số cài đặt có thể không tương thích với những người khác. Vì lý do này, WCF bao gồm một tập hợp các cam kết ràng buộc được xác định trước. Những cam kết ràng buộc (còn được gọi là ràng buộc tiêu chuẩn) được thiết kế để bao gồm hầu hết các yêu cầu ứng dụng. Nếu không có các ràng buộc tiêu chuẩn có sự kết hợp của tính năng mà một ứng dụng dịch vụ yêu cầu, bạn có thể tạo ra ràng. | Session 2 Introduction to Microsoft .NET Framework Technologies 47 Demonstration 6 Creating a Sequential Workflow -Ji . 11 5 Creating a Sequential Workflow In this demonstration you will see how you can create an application that uses a sequential workflow. Key Point The key point of this demonstration is You can add activities to a Windows Workflow application and configure the workflow to process the activities sequentially. Microsoft I Learning 48 Session 2 Introduction to Microsoft .NET Framework Technologies Using Activities in Workflows An activity represents an action in a workflow and can be Simple or composite Sequential Event driven Windows Workflow Foundation framework includes a default set of activities Activities are the fundamental building blocks of workflows. A workflow is a set of activities organized hierarchically in a tree structure. Once all of the activities in a given flow path are finished running the workflow instance completes. An activity represents an action in a workflow. It can be a simple action such as a delay or it can be a composite activity that consists of several child activities. An activity like a workflow can be sequential which means that the order of its actions is specified at design time. Or the activity can be event-driven which means that the order of its actions is determined at run time in response to external events. The Windows Workflow Foundation framework includes a default set of activities that provide functionality for control flow conditions event handling state management and communicating with applications and services. When designing workflows you can use the activities provided by Windows Workflow Foundation and you can create your own activities. Session 2 Introduction to Microsoft .NET Framework Technologies 49 The following table lists a sample of the activities in the Windows Workflow Foundation framework activity set. Activity Description InvokeWebService Makes a call out to a Web service