Question

我有一个分配了异步执行任务的组件。完成后，它将触发两个事件中的一个来表示成功或失败。我需要将所有这些转换为同步调用：

Public Function AssignTask(o As Object) as Boolean
    Dim component As New X.Y.Z.Component()
    component.DoSomethingWith(o)
    AddHandler component.OnSuccess, AddressOf OnSuccess
    AddHandler component.OnError, AddressOf OnError

    Return True 'Need to return success or not.
End Sub

Private Sub OnSuccess(sender As Object, e As System.EventArgs)
    'Success! :)
End Sub

Private Sub OnError(sender As Object, e As System.EventArgs)
    'Error! :(
End Sub

我很困惑，至于如何让事件触发主方法成功或失败。

谢谢！

Answer 1

你可以做这样的事情（这不是线程安全的，所以如果你为不同的线程调用它会不会很好）

Private _completedFlag As Boolean
Private _completionResult As Boolean

Public Function AssignTask(o As Object) as Boolean
    Dim component As New X.Y.Z.Component()
    _completedFlag = False
    AddHandler component.OnSuccess, AddressOf OnSuccess
    AddHandler component.OnError, AddressOf OnError
    component.DoSomethingWith(o)
    Do Until _completedFlag
        'wait
    Loop
    Return _completionResult
End Sub

Private Sub OnSuccess(sender As Object, e As System.EventArgs)
    _completionResult = True
    _completedFlag = True
End Sub

Private Sub OnError(sender As Object, e As System.EventArgs)
    _completionResult = False
    _completedFlag = True
End Sub

在实际调用方法之前，我已将AddHandler移动到，因为它可能在连接处理程序之前完成

在VB.NET中将带有事件的异步调用转换为同步

1 个答案: