Question

我在Vb.net中有一个项目，并且有一个带有dotnet framework 3.5的windows表单应用程序。我正在使用Emum存储和处理任务As：

Public Enum TaskStatus
        none = 0
        completed = 2
        executing = 4
        executed = 8
        errors = 16      '' Means task got some error in performing some operations
        uploaded = 32
        incomplete = 64  '' Means Task Was Aborted or Process Stopped in between
End Enum

一个功能是处理任务，另一个是检查其完成状态，如

Private Function Manage()
        Dim ts As TaskStatus = TaskStatus.none
        '' Performing Tasks 
        ts = TaskStatus.executing
        '' Task Performed with Error
        ts = TaskStatus.errors Or TaskStatus.executed
        '' Task Uploading
        ts = ts Or TaskStatus.uploaded
        ts = ts Or TaskStatus.completed
        ts = TaskStatus.none
        CheckStatus(ts)
End Function

 Private Function CheckStatus(ByVal ts As TaskStatus)
    ' Now i Want to check
    If ts And (TaskStatus.uploaded Or TaskStatus.errors) Then
        '' Which one of these(Below) is Correct
    End If
    If ts = (TaskStatus.uploaded Or TaskStatus.errors) Then
        '' Which one of these(Above one) is Correct
    End If
    If ts And TaskStatus.incomplete Then
        '' Is it Correct way to check for incompletion
    End If
    If ts And TaskStatus.completed Then
        '' Task is Completed
        '' Is is correct way to check Task Completed
    End If
End Function

在Function CheckStatus中，我想知道使用enum组合进行操作的正确方法吗？

Answer 1

这是一个可能有助于一些想法的课程。请注意额外的枚举值all和枚举上的flags属性。

Public Class StatusTask
    <Flags> _
    Public Enum TaskStatus
        none = 0
        completed = 2
        executing = 4
        executed = 8
        errors = 16      '' Means task got some error in performing some operations
        uploaded = 32
        incomplete = 64  '' Means Task Was Aborted or Process Stopped in between
        all = -1
    End Enum

    Public ThisStatus As TaskStatus = TaskStatus.none

    Public Sub SetStatus(aStatus As TaskStatus)
        Me.ThisStatus = aStatus
    End Sub

    Public Sub AddStatus(aStatus As TaskStatus)
        Me.ThisStatus = Me.ThisStatus Or aStatus
    End Sub

    Public Sub ClearStatus(aStatus As TaskStatus)
        Me.ThisStatus = Me.ThisStatus And (aStatus Xor TaskStatus.all)
    End Sub

    Public Function HasStatus(aStatus As TaskStatus) As Boolean
        ''if HasFlag not found use
        ''Return (Me.ThisStatus And aStatus) = aStatus

        Return Me.ThisStatus.HasFlag(aStatus)
    End Function
End Class

和一些用法

    Dim foo As New StatusTask
    'set some status
    foo.SetStatus(StatusTask.TaskStatus.completed)
    foo.AddStatus(StatusTask.TaskStatus.executed)
    foo.AddStatus(StatusTask.TaskStatus.incomplete Or StatusTask.TaskStatus.uploaded)
    Debug.WriteLine(foo.ThisStatus)

    'do some checks
    'single
    If foo.HasStatus(StatusTask.TaskStatus.completed) Then
        Stop
    End If

    'multiple(both must be set)
    If foo.HasStatus(StatusTask.TaskStatus.completed) AndAlso foo.HasStatus(StatusTask.TaskStatus.incomplete) Then
        Stop
    End If
    'multiple(both must be set) alternative
    If foo.HasStatus(StatusTask.TaskStatus.completed Or StatusTask.TaskStatus.executed) Then
        Stop
    End If

    'multiple(either set)
    If foo.HasStatus(StatusTask.TaskStatus.errors) OrElse foo.HasStatus(StatusTask.TaskStatus.incomplete) Then
        Stop
    End If

    'clear status
    foo.ClearStatus(StatusTask.TaskStatus.errors) 'errors not set
    Debug.WriteLine(foo.ThisStatus)
    foo.ClearStatus(StatusTask.TaskStatus.completed Or StatusTask.TaskStatus.uploaded)
    Debug.WriteLine(foo.ThisStatus)
    foo.ClearStatus(StatusTask.TaskStatus.incomplete)
    Debug.WriteLine(foo.ThisStatus)
    foo.ClearStatus(StatusTask.TaskStatus.all)
    Debug.WriteLine(foo.ThisStatus)

Answer 2

我会说你在这里所做的是非常好的方式，但如果你想检查哪一个是正确的，你使用or，我建议将它们分成不同的语句。

除此之外，我还建议使用elseif代替正常的if语句，以保证一些时间和资源：）

我将如何做到这一点：

Private Function CheckStatus(ByVal ts As TaskStatus)
' Now i Want to check
If ts = TaskStatus.uploaded Then
    'Uploaded
Elseif ts = TaskStatus.errors Then
    'Error
Elseif ts = TaskStatus.incomplete Then
    'Incomplete
Elseif ts = TaskStatus.completed Then
    ' Task is Completed
End If
End Function

这只是我如何做到的快速草图，但如果我误读了某些内容，请告诉我。

枚举组合，正确的方式 - vb.net

2 个答案: