24

我有其中之一（来源：netdna-cdn.com）纳米控制的

并想使用它上面的滑块来控制 Excel，就像 Excel 表单控件滚动条之一一样。

我已经设法为 VBA 修改了这段代码，但它非常不稳定。谁能帮我稳定一下？我认为如果 MidiIn_Event 函数返回的速度不够快，它可能会崩溃，但我可能错了。

提前致谢。

Public Const CALLBACK_FUNCTION = &H30000
Public Declare Function midiInOpen Lib "winmm.dll" 
        (lphMidiIn As Long, 
        ByVal uDeviceID As Long, ByVal dwCallback As Any, 
        ByVal dwInstance As Long, ByVal dwFlags As Long) As Long
Public Declare Function midiInClose Lib "winmm.dll" 
        (ByVal hMidiIn As Long) As Long
Public Declare Function midiInStart Lib "winmm.dll" 
        (ByVal hMidiIn As Long) As Long
Public Declare Function midiInStop Lib "winmm.dll" 
        (ByVal hMidiIn As Long) As Long
Public Declare Function midiInReset Lib "winmm.dll" 
        (ByVal hMidiIn As Long) As Long
Private ri As Long

Public Sub StartMidiFunction()
    Dim lngInputIndex As Long
    lngInputIndex=0
    Call midiInOpen(ri, lngInputIndex, AddressOf MidiIn_Event, 
            0, CALLBACK_FUNCTION)
    Call midiInStart(ri)
End Function

Public Sub EndMidiRecieve()
    Call midiInReset(ri)
    Call midiInStop(ri)
    Call midiInClose(ri)
End Sub

Public Function MidiIn_Event(ByVal MidiInHandle As Long, 
        ByVal Message As Long, ByVal Instance As Long, 
        ByVal dw1 As Long, ByVal dw2 As Long) As Long

    'dw1 contains the midi code
    If dw1 > 255 Then 'Ignore time codes
        Call MsgBox(dw1)    'This part is unstable
    End If
End Function
4

3 回答 3

2

问题可能是MsgBox：

  • 由于 MIDI 事件使用回调，它们很可能从另一个线程运行。VBA 本质上是单线程的（参见例如VBA 中的多线程），因此尝试从另一个线程显示模态对话框可能会导致问题（未定义的行为、崩溃、其他任何事情......）
  • MIDI 通常会触发大量的事件（滑块或旋钮的最微小的移动都会触发一个事件），因此移动某个明显的量可能会导致数百个事件。在每个事件中显示一个对话框（需要单击确定）可能是一个问题。

为了测试，请尝试替换Call MsgBox(dw1)为，Debug.Print dw1以便将值仅打印在立即窗口中，这应该更加稳定。如果您尝试执行一些简单的操作（例如，更新单元格中的值、滚动窗口），只要每次调用在下一个事件之前完成，您就可以摆脱它。MidiIn_Event

一个更复杂但更稳定的解决方案可能是将数据点推送到事件处理程序中的队列中，并在 VBA 中使用重复计时器，从队列中弹出项目并在 VBA 线程上执行一些操作。

于 2013-01-24T23:33:40.043 回答
1

这太酷了：D

但是上面提到的消息框会杀死它，但是删除消息框可能不会有太大帮助。您也希望尽量减少 excel 的流量，因为 vba->excel 不会是瞬时的。

Soooo的解决方案是

在工作簿上启动宏

    Public lngMessage As String

    Private Sub Workbook_Open()
        alertTime = Now + TimeValue("00:00:01")
        Application.OnTime alertTime, "EventMacro"
    End Sub
    Sub EventMacro()
        ActiveSheet.Cells(1, 1).Value = lngMessage
        alertTime = Now + TimeValue("00:00:01")
    End Sub

    Public Function MidiIn_Event(ByVal MidiInHandle As Long, ByVal Message As Long, ByVal Instance As Long, ByVal dw1 As Long, ByVal dw2 As Long) As Long
        'dw1 contains the midi code
        If dw1 > 255 Then 'Ignore time codes
            lngMessage = dw1    'This part is now happy
        End If
    End Function
于 2013-01-25T14:07:10.570 回答
1

您需要一个通用函数来处理 MidiIn_Event 一个给出的数据，在我下面的示例中，该函数是 runClock() 一个。

我这样做是为了能够使用状态栏来计算消息的键和时钟类型。

Option Explicit

Private Const CALLBACK_FUNCTION = &H30000

'MIDI Functions here: https://docs.microsoft.com/en-us/windows/win32/multimedia/midi-functions
#If Win64 Then
    Private Declare PtrSafe Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As LongPtr)
    Private Declare PtrSafe Function timeGetTime Lib "winmm.dll" () As Long
    'For MIDI device INPUT
    Private Declare PtrSafe Function midiInOpen Lib "winmm.dll" (lphMidiIn As LongPtr, ByVal uDeviceID As LongPtr, ByVal dwCallback As LongPtr, ByVal dwInstance As LongPtr, ByVal dwFlags As LongPtr) As Long
    Private Declare PtrSafe Function midiInClose Lib "winmm.dll" (ByVal hMidiIn As LongPtr) As Long
    Private Declare PtrSafe Function midiInStart Lib "winmm.dll" (ByVal hMidiIn As LongPtr) As Long
    Private Declare PtrSafe Function midiInStop Lib "winmm.dll" (ByVal hMidiIn As LongPtr) As Long
    Private Declare PtrSafe Function midiInReset Lib "winmm.dll" (ByVal hMidiIn As LongPtr) As Long
#Else
    Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
    Private Declare Function timeGetTime Lib "winmm.dll" () As Long
    'For MIDI device INPUT
    Private Declare Function midiInOpen Lib "winmm.dll" (lphMidiIn As Long, ByVal uDeviceID As Long, ByVal dwCallback As Long, ByVal dwInstance As Long, ByVal dwFlags As Long) As Long
    Private Declare Function midiInClose Lib "winmm.dll" (ByVal hMidiIn As Long) As Long
    Private Declare Function midiInStart Lib "winmm.dll" (ByVal hMidiIn As Long) As Long
    Private Declare Function midiInStop Lib "winmm.dll" (ByVal hMidiIn As Long) As Long
    Private Declare Function midiInReset Lib "winmm.dll" (ByVal hMidiIn As Long) As Long
#End If

#If Win64 Then
    Private mlngCurDevice      As Long
    Private mlngHmidi          As LongPtr
#Else
    Private mlngCurDevice      As Long
    Private mlngHmidi          As Long
#End If

Private ClockTicks             As Integer
Private Notes                  As Integer
Private Looper                 As Long
Private LongMessage            As Long
Private actualTime             As Long

Public Sub runClock()

    'When canceled become able to close opened Input devices (For ESC press)
    On Error GoTo handleCancel
    Application.EnableCancelKey = xlErrorHandler

    With Application
        .Calculation = xlCalculationManual
        .ScreenUpdating = False
        '.DisplayStatusBar = False
        '.EnableEvents = False
    End With

    mlngCurDevice = 8 'My Device is 8 but yours is 0
    Notes = 0
    Looper = 0

    'Open Input Device
    Call midiInOpen(mlngHmidi, mlngCurDevice, AddressOf MidiIn_Event, 0, CALLBACK_FUNCTION)

    'Ends only when Status is different from 0
    Do While Notes < 10
        'Reset Status count
        ClockTicks = 0

        'Begins lissinting the MIDI input
        Call midiInStart(mlngHmidi)

        'Loops until the right message is given <= 255 and > 0
        Do While ClockTicks < 1000 And Notes < 10
            'Sleep if needed
            Sleep 10
            Application.StatusBar = "Looper=" & Looper & " | Notes=" & Notes & " | ClockTicks=" & ClockTicks & " | Message=" & LongMessage
            Looper = Looper + 1
            'DoEvents enables ESC key
            If Abs(timeGetTime - actualTime) > 3000 Then
                DoEvents
                actualTime = timeGetTime
            End If
        Loop

        'Ends lisingting the MIDI input
        Call midiInReset(mlngHmidi)
        Call midiInStop(mlngHmidi)

    Loop

    'Closes Input device
    Do While midiInClose(mlngHmidi) <> 0
    Loop

    With Application
        .Calculation = xlCalculationAutomatic
        .ScreenUpdating = True
        .DisplayStatusBar = True
        .EnableEvents = True
    End With

    MsgBox "ENDED WITH SUCCESS", , "Message:"

    'Close all opened MIDI Inputs when canceled (ESC key pressed)
handleCancel:
        If Err.Number = 18 Then

            'Ends lisingting the MIDI input
            Call midiInReset(mlngHmidi)
            Call midiInStop(mlngHmidi)
            Do While midiInClose(mlngHmidi) <> 0
            Loop

            With Application
                .Calculation = xlCalculationAutomatic
                .ScreenUpdating = True
                .DisplayStatusBar = True
                .EnableEvents = True
            End With

            MsgBox "ENDED WITH SUCCESS", , "Message:"

        End If

End Sub

Private Function MidiIn_Event(ByVal mlngHmidi As Long, ByVal Message As Long, ByVal Instance As Long, ByVal dw1 As Long, ByVal dw2 As Long) As Long

    'The value 963 is the MIM_DATA concerning regular MIDI messages
    If Message = 963 Then
        LongMessage = Message
        If dw1 > 255 Then
            Notes = Notes + 1
        Else
            ClockTicks = ClockTicks + 1
        End If
    End If

End Function

出于某种原因，在接收 MIDI 数据（如时钟同步）时按下 ESC 键时会出现问题，尽管其他一切正常，但 ESC 键多次使脚本崩溃。但是，如果您在输入 MIDI 消息期间不使用 ESC 键，则不会出现此问题。

不过，我想知道为什么在接收时钟信号时按 ESC 键会使脚本崩溃。

您只需要使全局变量适应您的需要。

希望我有所帮助。

于 2019-12-29T08:51:32.013 回答