如何在VB.NET中编写异步子程序?
重复接口:如何在VB.NET中编写异步子程序?,vb.net,asynchronous,async-await,Vb.net,Asynchronous,Async Await,重复接口: Public Class LoginManager Implements ILoginManager Private ReadOnly _iLoginRepository As ILoginRepository Public Sub New() _iLoginRepository = New LoginRepository() End Sub Public Async Sub InsertFailedLoginAttempt(
Public Class LoginManager
Implements ILoginManager
Private ReadOnly _iLoginRepository As ILoginRepository
Public Sub New()
_iLoginRepository = New LoginRepository()
End Sub
Public Async Sub InsertFailedLoginAttempt(failedLoginAttempt As FailedLogin) Implements ILoginManager.InsertFailedLoginAttempt
'Example of the S in Solid (Single Repsonsibilty)
'Need to call these method async. But await errors
_iLoginRepository.InsertFailedLoginAttemptAsync(failedLoginAttempt)
_iLoginRepository.InsertFailedLoginAttemptIntoLoginMasterAsync(failedLoginAttempt)
End Sub
End Class
Public Class LoginRepository
Implements ILoginRepository
Public ReadOnly _applicationDBContext As New ApplicationDBContext()
Public Async Sub InsertFailedLoginAttemptAsync(failedLoginAttempt As FailedLogin) Implements ILoginRepository.InsertFailedLoginAttemptAsync
Using _applicationDBContext
_applicationDBContext.RepFailedLogins.Add(failedLoginAttempt)
Await _applicationDBContext.SaveChangesAsync()
End Using
End Sub
Public Async Sub InsertFailedLoginAttemptIntoLoginMasterAsync(failedLoginAttempt As FailedLogin) Implements ILoginRepository.InsertFailedLoginAttemptIntoLoginMasterAsync
Using _applicationDBContext
_applicationDBContext.RepFailedLoginMasters.Add(failedLoginAttempt)
Await _applicationDBContext.SaveChangesAsync()
End Using
End Sub
''' <summary>
''' Determine whether a user is authenticated, be it an internal or external user
''' I have condensed two methods into one
''' </summary>
''' <param name="cID"></param>
''' <param name="password"></param>
''' <param name="IsExternalUser"></param>
''' <returns></returns>
Public Async Function IsUserAuthenticatedAsync(cID As String, password As String, IsExternalUser As Boolean) As Task(Of Boolean) Implements ILoginRepository.IsUserAuthenticatedAsync
If (IsExternalUser And String.IsNullOrEmpty(password)) Then
Throw New ArgumentNullException("External user requires password")
End If
Dim user As Chaser
Dim toRet As Boolean
Using _applicationDBContext
'Two ways to use LINQ
'First is LINQ Lambda sybntax(little harder to read)
user = Await _applicationDBContext.Chasers.Where(Function(x) x.CID = cID).FirstOrDefaultAsync()
'Second is LINQ Query syntax(looks more like SQL just more verbose
'user = From x In _applicationDBContext.Chasers
' Where x.CID = cID
' Select x
End Using
If IsNothing(user) Then
toRet = False
ElseIf Not IsExternalUser And Not IsNothing(user) Then
toRet = True
ElseIf IsExternalUser And user.Hash_Password = password Then
toRet = True
End If
Return toRet
End Function
End Class
存储库实现:
Public Interface ILoginRepository
Function IsUserAuthenticatedAsync(ByVal cID As String, ByVal password As String, ByVal IsExternalUser As Boolean) As Task(Of Boolean)
Sub InsertFailedLoginAttemptAsync(ByVal failedLoginAttempt As FailedLogin)
Sub InsertFailedLoginAttemptIntoLoginMasterAsync(ByVal failedLoginAttempt As FailedLogin)
End Interface
我正在尝试在我的管理器中调用InsertFailedLoginAtterAsync存储库方法。这是一个异步方法,但我无法等待该方法。我怎样才能使这种方法成为人们期待的
我相信这与接口有关,而不是像C中那样使其成为异步方法,但我无法做到这一点。通过Nkosi的回复修复: 接口:
Public Class LoginManager
Implements ILoginManager
Private ReadOnly _iLoginRepository As ILoginRepository
Public Sub New()
_iLoginRepository = New LoginRepository()
End Sub
Public Async Sub InsertFailedLoginAttempt(failedLoginAttempt As FailedLogin) Implements ILoginManager.InsertFailedLoginAttempt
'Example of the S in Solid (Single Repsonsibilty)
'Need to call these method async. But await errors
_iLoginRepository.InsertFailedLoginAttemptAsync(failedLoginAttempt)
_iLoginRepository.InsertFailedLoginAttemptIntoLoginMasterAsync(failedLoginAttempt)
End Sub
End Class
Public Class LoginRepository
Implements ILoginRepository
Public ReadOnly _applicationDBContext As New ApplicationDBContext()
Public Async Sub InsertFailedLoginAttemptAsync(failedLoginAttempt As FailedLogin) Implements ILoginRepository.InsertFailedLoginAttemptAsync
Using _applicationDBContext
_applicationDBContext.RepFailedLogins.Add(failedLoginAttempt)
Await _applicationDBContext.SaveChangesAsync()
End Using
End Sub
Public Async Sub InsertFailedLoginAttemptIntoLoginMasterAsync(failedLoginAttempt As FailedLogin) Implements ILoginRepository.InsertFailedLoginAttemptIntoLoginMasterAsync
Using _applicationDBContext
_applicationDBContext.RepFailedLoginMasters.Add(failedLoginAttempt)
Await _applicationDBContext.SaveChangesAsync()
End Using
End Sub
''' <summary>
''' Determine whether a user is authenticated, be it an internal or external user
''' I have condensed two methods into one
''' </summary>
''' <param name="cID"></param>
''' <param name="password"></param>
''' <param name="IsExternalUser"></param>
''' <returns></returns>
Public Async Function IsUserAuthenticatedAsync(cID As String, password As String, IsExternalUser As Boolean) As Task(Of Boolean) Implements ILoginRepository.IsUserAuthenticatedAsync
If (IsExternalUser And String.IsNullOrEmpty(password)) Then
Throw New ArgumentNullException("External user requires password")
End If
Dim user As Chaser
Dim toRet As Boolean
Using _applicationDBContext
'Two ways to use LINQ
'First is LINQ Lambda sybntax(little harder to read)
user = Await _applicationDBContext.Chasers.Where(Function(x) x.CID = cID).FirstOrDefaultAsync()
'Second is LINQ Query syntax(looks more like SQL just more verbose
'user = From x In _applicationDBContext.Chasers
' Where x.CID = cID
' Select x
End Using
If IsNothing(user) Then
toRet = False
ElseIf Not IsExternalUser And Not IsNothing(user) Then
toRet = True
ElseIf IsExternalUser And user.Hash_Password = password Then
toRet = True
End If
Return toRet
End Function
End Class
经理方法:
Public Interface ILoginRepository
Function IsUserAuthenticatedAsync(ByVal cID As String, ByVal password As String, ByVal IsExternalUser As Boolean) As Task(Of Boolean)
Function InsertFailedLoginAttemptAsync(ByVal failedLoginAttempt As FailedLogin) As Task
Function InsertFailedLoginAttemptIntoLoginMasterAsync(ByVal failedLoginAttempt As FailedLogin) As Task
End Interface
SUB不应该是异步的。事件处理程序是该规则的唯一例外。您正在等待只能从函数返回的任务。如果目的是使接口异步,那么所有成员都需要是返回任务或其派生的函数
Async在使用时会一直冒泡。也就是说,如果可能的话,应该重构ILoginManager和ILoginRepository,以遵循正确的语法
参考:Subs不应该是异步的。事件处理程序是该规则的唯一例外。您正在等待只能从函数返回的任务。如果目的是使接口异步,那么所有成员都需要是返回任务或其派生的函数。