(VB.NET) Async Methods Returning an String

Demonstrates how to call an asynchronous method that returns a string. This example sends an HTTPS GET request to a URL and gets the HTML response.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim http As New Chilkat.Http

Dim task As Chilkat.Task = http.QuickGetStrAsync("https://www.chilkatsoft.com/helloWorld.html")
If (http.LastMethodSuccess = False) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If

' Start the background task.
Dim success As Boolean = task.Run()
If (Not success) Then
    Debug.WriteLine(task.LastErrorText)

    Exit Sub
End If


' The application is now free to do anything else
' while the email is being sent.

' For this example, we'll simply sleep and periodically
' check to see if the HTTPS GET if finished.
While task.Finished <> True
    ' Sleep 100 ms.
    task.SleepMs(100)
End While

' A finished task could be one that was canceled, aborted, or truly finished.  

' If the task was "canceled", it was canceled prior to actually starting.  This could
' happen if the task was canceled while waiting in a thread pool queue to be scheduled by Chilkat's
' background thread pool scheduler.  

' If the task was "aborted", it indicates that it was canceled while running in a background thread.  
' The ResultErrorText will likely indicate that the task was aborted.

' If the task "completed", then it ran to completion, but the actual success/failure of the method
' is determined by the result obtained via a GetResult* method.  (A "completed" task will
' have a StatusInt equal to 7.   If the task finished, but was not completed, then it must've
' been aborted or canceled:
If (task.StatusInt <> 7) Then
    Debug.WriteLine("Task did not complete.")
    Debug.WriteLine("task status: " & task.Status)

    Exit Sub
End If


' The QuickGetStr method returns a string.  Therefore, after the task is finished,
' we can get the string result by calling GetResultString.  This is the return value had
' we called QuickGetStr synchronously.
Dim html As String = task.GetResultString()

Debug.WriteLine(html)