I am really enjoying getting more and more into the new async ctp. Something that stumped me up to now, was how do I run a void method asynchronously.
For instance, suppose I have the following workflow that I want to run.
private void DoWorkFlowSync()
{
txtStatus.Text = "Step 1";
Step1Workflow();
txtStatus.Text = "Step 2";
Step2Workflow();
txtStatus.Text = "Step 3";
Step3Workflow();
txtStatus.Text = "Done";
}
private void Step1Workflow()
{
Thread.Sleep(1000);
}
private void Step2Workflow()
{
Thread.Sleep(1000);
}
private void Step3Workflow()
{
Thread.Sleep(1000);
}
This is it in its synchronous state, if I try and run it asynchronously my initial attempts would be to code the DoWorkFlowSync as follows.
private async void DoWorkFlowAsync()
{
txtStatus.Text = "Step 1";
await Step1Workflow();
txtStatus.Text = "Step 2";
await Step2Workflow();
txtStatus.Text = "Step 3";
await Step3Workflow();
txtStatus.Text = "Done";
} To which the compiler would respond with a compile time error with the following…
Error 1 Cannot await ‘void’
So, a bit of a dilemma. I don’t want to have to rewrite each individual method (i.e. Step1Wroflow) to be of type Task. It would be doable if this was a small project but I want to be able to refactor large projects with appropriate asynchronous calls without going to deep into the project. Eventually I made a mind shift and found the following to work.
private async void DoWorkFlowAsync()
{
txtStatus.Text = "Step 1";
await TaskEx.Run(() => Step1Workflow());
txtStatus.Text = "Step 2";
await TaskEx.Run(() => Step2Workflow());
txtStatus.Text = "Step 3";
await TaskEx.Run(() => Step3Workflow());
txtStatus.Text = "Done";
} This worked perfectly, the UI was responsive and I have a workflow that is easy to read.
For those that are interested in learning more about the new async ctp go to the forum
