How to call an asynchronous method from a view?

Question

I have an async method in a controller that has an id parameter. In my view, I want to have a button that when clicked it passes a @document.SubmissionId variable to the function and execute it. How can I achieve that? Here is what I have so far:

Controller

private async Task<ActionResult> onPostSaveImage(string id){}

View

<input type="button" value="Send Images" class="btn btn-xs btn-outline-primary" onclick="location.href='@Url.Action("onPostSaveImage", "ICRDocumentPending")?id=' + @document.SubmissionId" />

Answer 1

Not enough just sign a method with async to be able work asynchronously when called from a view. It is necessary to derive your controller class from System.Web.Mvc.AsyncController, which implements IAsyncController interface. And code will become like below:

public class ICRDocumentPendingController : AsyncController
{
    public async Task<ActionResult> onPostSaveImage(string id)
    {           
        return await Task<ActionResult>.Factory.StartNew(() =>
        {
            /*  some code */
            //...

            return View("ViewName", (object)id); 
         });
     }
     //...
}

View code:

<input type="button" value="Send Images" 
       class="btn btn-xs btn-outline-primary"
       onclick="location.href='@Url.Action("onPostSaveImage", "ICRDocumentPending", new { id = document.SubmissionId }))'" />