PowerBuilder

Async Methods Returning an Object

See more Async Examples

Demonstrates how to call an asynchronous method that returns an object. This example reads email from a POP3 server using the Async versions of the Chilkat methods. PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Mailman
oleobject loo_Task
integer li_MaxWaitMs
integer li_NumMessages
oleobject loo_Email
integer i

li_Success = 0

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

li_Success = 0

loo_Mailman = create oleobject
li_rc = loo_Mailman.ConnectToNewObject("Chilkat.MailMan")
if li_rc < 0 then
    destroy loo_Mailman
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// Set the POP3 server's hostname
loo_Mailman.MailHost = "pop.example.com"

// Set the POP3 login/password and any other requirements..
loo_Mailman.PopUsername = "myLogin"
loo_Mailman.PopPassword = "myPassword"
loo_Mailman.PopSsl = 1
loo_Mailman.MailPort = 995

// Connect to the POP3 server:
loo_Task = loo_Mailman.Pop3BeginSessionAsync()
if loo_Mailman.LastMethodSuccess = 0 then
    Write-Debug loo_Mailman.LastErrorText
    destroy loo_Mailman
    return
end if

// Start the background task.
li_Success = loo_Task.Run()
if not li_Success then
    Write-Debug loo_Task.LastErrorText
    destroy loo_Task
    destroy loo_Mailman
    return
end if

// Wait for the POP3 connect task to finish.
// The 1/0 returned by Wait applies to the Wait method call, not the task.
li_MaxWaitMs = 30000
li_Success = loo_Task.Wait(li_MaxWaitMs)
if not li_Success OR (loo_Task.StatusInt <> 7) OR (loo_Task.TaskSuccess <> 1) then
    if not li_Success then
        // The task.LastErrorText applies to the Wait method call.
        Write-Debug loo_Task.LastErrorText
    else
        // The ResultErrorText applies to the underlying task method call (i.e. the Pop3BeginSession)
        Write-Debug loo_Task.Status
        Write-Debug loo_Task.ResultErrorText
    end if

    destroy loo_Task
    destroy loo_Mailman
    return
end if

destroy loo_Task

// Get the number of messages in the mailbox.
loo_Task = loo_Mailman.GetMailboxCountAsync()

// To keep the example short, we'll skip handling failures.
// The failures would be handled in the same way as shown above.

li_Success = loo_Task.Run()
li_Success = loo_Task.Wait(li_MaxWaitMs)
li_NumMessages = loo_Task.GetResultInt()
destroy loo_Task
if li_NumMessages = 0 then
    destroy loo_Mailman
    return
end if

loo_Email = create oleobject
li_rc = loo_Email.ConnectToNewObject("Chilkat.Email")

for i = 1 to li_NumMessages

    loo_Task = loo_Mailman.FetchByMsgnumAsync(i)
    if loo_Mailman.LastMethodSuccess = 0 then
        Write-Debug loo_Mailman.LastErrorText
        destroy loo_Mailman
        destroy loo_Email
        return
    end if

    li_Success = loo_Task.Run()
    li_Success = loo_Task.Wait(li_MaxWaitMs)
    if not li_Success OR (loo_Task.StatusInt <> 7) OR (loo_Task.TaskSuccess <> 1) then
        if not li_Success then
            // The task.LastErrorText applies to the Wait method call.
            Write-Debug loo_Task.LastErrorText
        else
            // The ResultErrorText applies to the underlying task method call (i.e. the FetchByMsgnum)
            Write-Debug loo_Task.Status
            Write-Debug loo_Task.ResultErrorText
        end if

        destroy loo_Task
        destroy loo_Mailman
        destroy loo_Email
        return
    end if

    // Each Chilkat object that can be a return value of an asynchronous task will
    // have a method named LoadTaskResult.  The object returned in the underlying
    // asynchronous method call is retrieved by calling LoadTaskResult. 

    // To say it another way: The application will provide a pre-existing object of
    // the desired return type (in this case it is an email object).  This object is
    // loaded by calling LoadTaskResult.  

    li_Success = loo_Email.LoadTaskResult(loo_Task)
    destroy loo_Task

    if not li_Success then
        Write-Debug loo_Email.LastErrorText
        destroy loo_Mailman
        destroy loo_Email
        return
    else
        Write-Debug loo_Email.From + ": " + loo_Email.Subject + "~n"
    end if

next


destroy loo_Mailman
destroy loo_Email