如何在VB.NET中调用这个方法？

Question

我正在制作一个使用 SOAP 网络服务的 VB.NET 应用程序。它在使用运行方法的同步模式下工作得很好。但我想使用这种异步方法：

Public Overloads Sub runAsync(ByVal callContext As CAdxCallContext, ByVal publicName As String, ByVal inputXml As String, ByVal userState As Object)
  If (Me.runOperationCompleted Is Nothing) Then
      Me.runOperationCompleted = AddressOf Me.OnrunOperationCompleted
 End If
 Me.InvokeAsync("run", New Object() {callContext, publicName, inputXml},   Me.runOperationCompleted, userState)
End Sub

怎么称呼它？

回调方法如何表示？

谢谢

彼得

Answer 1

TaskCompletionSource 将是用异步方法包装基于事件的方法的正确工具。

创建接受 TaskCompletionSource 实例作为参数的完成事件处理程序。

Public Sub OperationCompleted(
  e As SomeEventArgs, 
  TaskCompletionSource(Of SoapResult) taskSource
)
  ' Use EventArgs of your client to determine were operation successful or not
  ' Here I am using common completion properties
  If e.Cancelled Then
    taskSource.TrySetCanceled()
    Exit Sub
  End If

  If e.HasError Then
    taskSource.TrySetException(e.Error)
    Exit Sub
  End If

  ' Should be success now
  taskSource.TrySetResult(e.Result) ' Result is an instance of type SoapResult
End Sub

异步方法returns任务，在本例中我们期望操作成功时返回SoapResult类型的实例

Public Function RunAsync(MyInputArguments args) As Task(Of SoapResult)
  Dim taskSource As New TaskCompletionSource(Of SoapResult)()

  Dim invokeArgs As New Object() { args.Context, args.PublicName, args.InputXml }

  ' Wrap our completion handler with the function 
  ' To satisfy soap callback signature
  Dim callback As Action(Of SomeEventArgs) = 
    Sub(e) Me.OperationCompleted(e, taskSource)

  InvokeAsync("run", invokeArgs, callback, args.UserState)

  Return taskSource.Task
End Function

现在我们可以使用 async-await

异步调用 Soap 客户端

Dim arguments As New With
{
  .Context = callContext,
  .PublicName = publicName,
  .InputXml = inputXml,
  .UserState = userState
}
Dim result As SoapResult = Await client.RunAsync(arguments)

Answer 2

感谢您的帮助，它让我走上了正轨。

我找到了如何使用异步方法调用和获取回调：

致电：

x3WebService.runAsync(callContext, webserv, params, UserState)

回调：

Public Sub RunAsyncCompleted(sender As Object, e As runCompletedEventArgs) Handles x3WebService.runCompleted

...

但是你必须声明“withevents” x3WebService class :

Public Class X3WebServices
  Private WithEvents x3WebService As CAdxWebServiceXmlCCServiceBasicAuth

你好，

彼得

如何在VB.NET中调用这个方法？

How to call this method in VB.NET?

vb.net

asynchronous

web-services