Workflow：添加工作流存储功能

数据库准备：

1. 创建database（这里我们用的是MSSQL。Workflow支持其它数据库，但是MSSQL是配置最方便，不要问我为什么！）。

2. 运行位于[%WINDIR%Microsoft.NETFrameworkv4.xxxSQLEN]的的脚本文件SqlWorkflowInstanceStoreSchema.sql和SqlWorkflowInstanceStoreLogic.sql。这时数据库中表应该类似于下图：

 

开工:

1. 在上一个项目的基础上，引入System.Activites.DurableInstancing和System.Runtime.DurableInstancing。如下图所示：

2. 修改Console Project的program.cs如下：

        static void Main(string[] args)
        {
            // Workflow Store of SQL Server
            SqlWorkflowInstanceStore store =
                new SqlWorkflowInstanceStore("Data Source=192.168.3.26;Initial Catalog=workflow_hour3;Persist Security Info=True;User ID=sa;Password=M@nager");

            AutoResetEvent syncEvent = new AutoResetEvent(false);

            Activity wf = new WorkflowsProject.Activity1();

            // Create the WorkflowApplication using the desired
            // workflow definition.
            WorkflowApplication wfApp = new WorkflowApplication(wf);

            // Assign workflow store to the current workflow
            wfApp.InstanceStore = store;

            wfApp.PersistableIdle = delegate(WorkflowApplicationIdleEventArgs e)
            {
                Console.WriteLine("Workflow {0} persisted at {1}",
                    e.InstanceId, System.DateTime.Now.ToLongTimeString());
                return PersistableIdleAction.Persist;
            };

            wfApp.Idle = delegate(WorkflowApplicationIdleEventArgs e)
            {
                Console.WriteLine("Workflow {0} idled at {1}",
                    e.InstanceId, System.DateTime.Now.ToLongTimeString());
                syncEvent.Set();
            };

            // Handle the desired lifecycle events.
            wfApp.Completed = delegate(WorkflowApplicationCompletedEventArgs e)
            {
                Console.WriteLine("Workflow {0} completed.", e.InstanceId.ToString());
                syncEvent.Set();
            };

            wfApp.Aborted = delegate(WorkflowApplicationAbortedEventArgs e)
            {
                Console.WriteLine("Workflow {0} terminated because {1}", e.InstanceId, e.Reason.Message);
                syncEvent.Set();
            };
            
            // Start the workflow.
            wfApp.Run();

            // Wait for Completed to arrive and signal that
            // the workflow is complete.
            syncEvent.WaitOne();

            // Keep the console screen alive when workflow comnpletes
            Console.WriteLine("Press enter to continue");
            Console.Read();
        }

3. 修改Delay的Duration为30秒，方便我们观察数据库的数据变化：

4. 运行。结果如下：

5. 在workflow persisted阶段，还没有到completed的时候，如果查看数据库中的[System.Activities.DurableInstancing].[InstancesTable]表，我们就会发现诸如如下的记录：

 

而当workflow运行到completed的时候，在查询这张表，就会发现这条记录已经不存在了。说明工作流的数据存储运行正确。