- Microsoft Windows Workflow Foundation 4.0 Cookbook
- Andrew Zhu
- 274字
- 2021-04-13 17:00:35
We can use Variable temporarily to store a value when a WF program is running. In this task, we will create a WF program that prints five numbers to the console in a loop. We will use the NumberCounter variable as a number counter.
- Create a workflow project:
Create a new Workflow Console Application under the
Chapter01solution and name the project asUseVariable. - Author a workflow:
Add a
Sequenceactivity, click the Sequence activity, create anInt32NumberCountervariable, and set its Scope to Sequence. Then, author the workflow as shown in the following screenshot. In the second Assign activity type NumberCounter=NumberCounter+1.
- Run it:
Set
UseVariableas Startup project. Press Ctrl+F5 to build and run the workflow without debugging. The application should run in a console window and print the following message:
To make the workflow logic easy to understand, translate the workflow into C# code. It will look like:
int NumberCounter = 0;
do
{
Console.WriteLine(NumberCounter);
NumberCounter++;
}while (NumberCounter <= 5);
While we can use arguments to flow data into and out of a workflow, we use Variable to store data in a workflow. Every variable has its scope, and can be accessed by activities within its scope. Variable in WF4 is pretty much like variables in imperative language such as C#.