FIRST WORKFLOW in Visual C#.NET

Drawing ECC200 in Visual C#.NET FIRST WORKFLOW

control the name Step2 and the description Step 2 in process. Add a handler like you did with the Step1 Code activity. Within the ExecuteCode handler for the Step2 Code activity, add a message box with a prompt of Step2 : Private Sub Step2_ExecuteCode(ByVal sender As System.Object, ByVal e As System.EventArgs) MsgBox("Step2") End Sub Finally, run the application. The Step1 message box appears first. If you don t click OK, the workflow will pause and wait until the message box is clicked. After the message box is clicked, the Step2 message box will appear. This shows that the workflow is sequential. No other external action was necessary to move the workflow from step one to step two. The best way to see what s happening is to step through the code line by line using the debugger. Set a breakpoint on the line of code creating the specific workflow activities within the Sub Main of the Module1.vb file: workflowInstance = workflowRuntime.CreateWorkflow(GetType(Workflow1)) Also, set a breakpoint on the second message box within the Workflow1 class. When you step through the code, you ll see the first code to be executed is the constructor (Sub New) of the Workflow1 class. While in the constructor, the Sub InitializeComponent is called. This sub creates all the necessary class instances to support the workflow. Although you created the workflow within the designer and you drew it out, this sub actually creates the instances and uses them. Once again, this shows that you can use the workflow namespaces and classes without the designers, but the designers build all this code for you. This sub also adds the necessary handlers that the designer automatically generated earlier. When the code execution comes back to the Sub Main, the workflow is started, then the workflow waits. Once the workflow begins to wait, the first activity within the workflow begins, because this is a Sequential workflow. That workflow fires the execute code handler because the activity was a Code activity. The first message box appears. Then, when you click OK, the breakpoint within the Step2_ExecuteCode sub in the Workflow1 class is executed, and the breakpoint at the second message box is hit. Finally, after you click OK on the message box, the End Sub of the Sub Main back in Module1 is encountered. The flow of control is as follows: 1. Sub Main begins. 2. Handlers are added. 3. An instance of the Workflowinstance class is created. 4. The specific workflow is assigned to the Workflowinstance (sequential in this case): a. The Workflow1 class constructor is executed. b. All properties of all activities within Workflow1 are set. 5. Workflowinstance is started. 6. Sub Main waits for the activities within the workflow to finish.

7. Each activity within the workflow is processed in this case, the ExecuteCode handler of each Code activity. 8. Sub Main completes.

One of the many workflows that needs to be implemented might need to have values passed into it. This might include needing to know the user name of a user, or to know a document name that is to be approved or not approved. The workflow can accept input parameters, which are defined within the workflow file as public write-only properties, or the workflow can provide back output parameters that are defined within the workflow file as read-only properties. The first step is to define the parameters that you want passed to the workflow as public write-only properties. Add two private integer variables to the Workflow1 class, one called InputValue1, and one called InputValue2. Define two public write-only properties, one called Input1 and the other called Input2. Then define the output parameter by defining a private integer called OutputResult, and a public read-only property called OutputValue. Here s the resulting code: Private InputValue1 As Integer Private InputValue2 As Integer Private OutputResult As Integer Public WriteOnly Property Input1() As Integer Set(ByVal value As Integer) InputValue1 = value End Set End Property Public WriteOnly Property Input2() As Integer Set(ByVal value As Integer) InputValue2 = value End Set End Property Public ReadOnly Property OutputValue() As Integer Get Return OutputResult End Get End Property Next, add OutputResult = InputValue1 + InputValue2 to the Step1_ExecuteCode sub before the message box: Private Sub Step1_ExecuteCode(ByVal sender As System.Object, ByVal e As System.EventArgs) OutputResult = InputValue1 + InputValue2 MsgBox("Step1") End Sub This line of code adds the local variables for the input parameters together and assigns the result to the local variable for the output parameter. Open the Module1.vb file and add a new