编辑：

已将其转换为VBA和VB.Net的BLOG post。
我从来不赞成Sendkeys。它们在某些情况下是可靠的，但并不总是如此。尽管如此，我对API有一个软角落。
您想要的可以实现，但是您必须确保要取消保护VBA的工作簿必须在单独的Excel示例中打开。
这里有一个例子
假设我们有一个工作簿，其VBA工程目前看起来像这样。

逻辑：

1.使用FindWindow查找“VBAProject密码”窗口的句柄
1.找到后，使用FindWindowEx在该窗口中找到编辑框的句柄
1.找到编辑框的句柄后，只需使用SendMessage对其进行写入。
1.使用FindWindowEx在该窗口中查找Buttons的句柄
1.找到OK按钮的句柄后，只需使用SendMessage单击它。

建议：

1.对于API的THIS是我可以推荐的最佳链接。
1.如果你想成为像FindWindow，FindWindowEx和SendMessage这样的API的高手，那么你可以使用一个工具，它可以为你提供系统进程，线程，窗口和窗口消息的图形视图。uuSpy或Spy++。
这是什么间谍++将显示你的“VBAProject密码”窗口

测试：

打开一个新的Excel示例并将下面的代码粘贴到一个模块中。

编码：

我已经注解了代码，所以你应该不会有任何问题理解它。

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
(ByVal lpClassName As String, ByVal lpWindowName As String) As Long
 
Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" _
(ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, _
ByVal lpsz2 As String) As Long

Private Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" _
(ByVal hwnd As Long, ByVal lpString As String, ByVal cch As Long) As Long
 
Private Declare Function GetWindowTextLength Lib "user32" Alias _
"GetWindowTextLengthA" (ByVal hwnd As Long) As Long

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
 
Dim Ret As Long, ChildRet As Long, OpenRet As Long
Dim strBuff As String, ButCap As String
Dim MyPassword As String

Const WM_SETTEXT = &HC
Const BM_CLICK = &HF5

Sub UnlockVBA()
    Dim xlAp As Object, oWb As Object
    
    Set xlAp = CreateObject("Excel.Application")
    
    xlAp.Visible = True
    
    '~~> Open the workbook in a separate instance
    Set oWb = xlAp.Workbooks.Open("C:\Sample.xlsm")
    
    '~~> Launch the VBA Project Password window
    '~~> I am assuming that it is protected. If not then
    '~~> put a check here.
    xlAp.VBE.CommandBars(1).FindControl(ID:=2578, recursive:=True).Execute

    '~~> Your passwword to open then VBA Project
    MyPassword = "Blah Blah"
    
    '~~> Get the handle of the "VBAProject Password" Window
    Ret = FindWindow(vbNullString, "VBAProject Password")
    
    If Ret <> 0 Then
        'MsgBox "VBAProject Password Window Found"
        
        '~~> Get the handle of the TextBox Window where we need to type the password
        ChildRet = FindWindowEx(Ret, ByVal 0&, "Edit", vbNullString)
        
        If ChildRet <> 0 Then
            'MsgBox "TextBox's Window Found"
            '~~> This is where we send the password to the Text Window
            SendMess MyPassword, ChildRet
        
            DoEvents
        
            '~~> Get the handle of the Button's "Window"
            ChildRet = FindWindowEx(Ret, ByVal 0&, "Button", vbNullString)
            
            '~~> Check if we found it or not
            If ChildRet <> 0 Then
                'MsgBox "Button's Window Found"
    
                '~~> Get the caption of the child window
                strBuff = String(GetWindowTextLength(ChildRet) + 1, Chr$(0))
                GetWindowText ChildRet, strBuff, Len(strBuff)
                ButCap = strBuff
    
                '~~> Loop through all child windows
                Do While ChildRet <> 0
                    '~~> Check if the caption has the word "OK"
                    If InStr(1, ButCap, "OK") Then
                        '~~> If this is the button we are looking for then exit
                        OpenRet = ChildRet
                        Exit Do
                    End If
    
                    '~~> Get the handle of the next child window
                    ChildRet = FindWindowEx(Ret, ChildRet, "Button", vbNullString)
                    '~~> Get the caption of the child window
                    strBuff = String(GetWindowTextLength(ChildRet) + 1, Chr$(0))
                    GetWindowText ChildRet, strBuff, Len(strBuff)
                    ButCap = strBuff
                Loop
    
                '~~> Check if we found it or not
                If OpenRet <> 0 Then
                    '~~> Click the OK Button
                    SendMessage ChildRet, BM_CLICK, 0, vbNullString
                Else
                    MsgBox "The Handle of OK Button was not found"
                End If
            Else
                 MsgBox "Button's Window Not Found"
            End If
        Else
            MsgBox "The Edit Box was not found"
        End If
    Else
        MsgBox "VBAProject Password Window was not Found"
    End If
End Sub

Sub SendMess(Message As String, hwnd As Long)
    Call SendMessage(hwnd, WM_SETTEXT, False, ByVal Message)
End Sub

我知道你已经锁定了这个新的答案，但我有几个问题与上述代码，主要是我在Office 64位（VBA7）工作。然而，我也使它的代码将在Excel的当前示例中工作，并添加了更多的错误检查和格式化它粘贴到一个单独的模块，只有方法UnlockProject暴露。
为了充分披露，我真的从这篇文章中的代码开始，尽管它是一个主题的变体。
代码还显示了条件编译常量，因此它应该同时兼容32位和64位版本的Excel。我使用this page来帮助我解决这个问题。
下面是代码，希望对大家有用：

Option Explicit

#If VBA7 Then
    Private Declare PtrSafe Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hwndParent As LongPtr, ByVal hwndChildAfter As LongPtr, ByVal lpszClass As String, ByVal lpszWindow As String) As LongPtr
    Private Declare PtrSafe Function GetParent Lib "user32" (ByVal hWnd As LongPtr) As LongPtr
    Private Declare PtrSafe Function GetDlgItem Lib "user32" (ByVal hDlg As LongPtr, ByVal nIDDlgItem As Long) As LongPtr ' nIDDlgItem = int?
    Private Declare PtrSafe Function GetDesktopWindow Lib "user32" () As LongPtr
    Private Declare PtrSafe Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As LongPtr, ByVal Msg As Long, ByVal wParam As Long, lParam As Any) As Long
    Private Declare PtrSafe Function SetFocusAPI Lib "user32" Alias "SetFocus" (ByVal hWnd As LongPtr) As LongPtr
    Private Declare PtrSafe Function LockWindowUpdate Lib "user32" (ByVal hWndLock As LongPtr) As Long
    Private Declare PtrSafe Function SetTimer Lib "user32" (ByVal hWnd As LongPtr, ByVal nIDEvent As LongPtr, ByVal uElapse As Long, ByVal lpTimerFunc As LongPtr) As LongPtr
    Private Declare PtrSafe Function KillTimer Lib "user32" (ByVal hWnd As LongPtr, ByVal uIDEvent As LongPtr) As Long
    Private Declare PtrSafe Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
#Else
    Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hwndParent As Long, ByVal hwndChildAfter As Long, ByVal lpszClass As String, ByVal lpszWindow As String) As Long
    Private Declare Function GetParent Lib "user32" (ByVal hWnd As Long) As Long
    Private Declare Function GetDlgItem Lib "user32" (ByVal hDlg As Long, ByVal nIDDlgItem As Long) As Long ' nIDDlgItem = int?
    Private Declare Function GetDesktopWindow Lib "user32" () As Long
    Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hWnd As Long, ByVal Msg As Long, ByVal wParam As Long, lParam As Any) As Long
    Private Declare Function SetFocusAPI Lib "user32" Alias "SetFocus" (ByVal hWnd As Long) As Long
    Private Declare Function LockWindowUpdate Lib "user32" (ByVal hWndLock As Long) As Long
    Private Declare Function SetTimer Lib "user32" (ByVal hWnd As Long, ByVal nIDEvent As Long, ByVal uElapse As Long, ByVal lpTimerFunc As Long) As Long
    Private Declare Function KillTimer Lib "user32" (ByVal hWnd As Long, ByVal uIDEvent As Long) As Long
    Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
#End If

Private Const WM_CLOSE As Long = &H10
Private Const WM_GETTEXT As Long = &HD
Private Const EM_REPLACESEL As Long = &HC2
Private Const EM_SETSEL As Long = &HB1
Private Const BM_CLICK As Long = &HF5&
Private Const TCM_SETCURFOCUS As Long = &H1330&
Private Const IDPassword As Long = &H155E&
Private Const IDOK As Long = &H1&

Private Const TimeoutSecond As Long = 2

Private g_ProjectName    As String
Private g_Password       As String
Private g_Result         As Long
#If VBA7 Then
    Private g_hwndVBE        As LongPtr
    Private g_hwndPassword   As LongPtr
#Else
    Private g_hwndVBE        As Long
    Private g_hwndPassword   As Long
#End If

Sub Test_UnlockProject()
    Select Case UnlockProject(ActiveWorkbook.VBProject, "Test")
        Case 0: MsgBox "The project was unlocked"
        Case 2: MsgBox "The active project was already unlocked"
        Case Else: MsgBox "Error or timeout"
    End Select
End Sub

Public Function UnlockProject(ByVal Project As Object, ByVal Password As String) As Long

#If VBA7 Then
    Dim lRet As LongPtr
#Else
    Dim lRet As Long
#End If
Dim timeout As Date

    On Error GoTo ErrorHandler
    UnlockProject = 1

    ' If project already unlocked then no need to do anything fancy
    ' Return status 2 to indicate already unlocked
    If Project.Protection <> vbext_pp_locked Then
        UnlockProject = 2
        Exit Function
    End If

    ' Set global varaibles for the project name, the password and the result of the callback
    g_ProjectName = Project.Name
    g_Password = Password
    g_Result = 0

    ' Freeze windows updates so user doesn't see the magic happening :)
    ' This is dangerous if the program crashes as will 'lock' user out of Windows
    ' LockWindowUpdate GetDesktopWindow()

    ' Switch to the VBE
    ' and set the VBE window handle as a global variable
    Application.VBE.MainWindow.Visible = True
    g_hwndVBE = Application.VBE.MainWindow.hWnd

    ' Run 'UnlockTimerProc' as a callback
    lRet = SetTimer(0, 0, 100, AddressOf UnlockTimerProc)
    If lRet = 0 Then
        Debug.Print "error setting timer"
        GoTo ErrorHandler
    End If

    ' Switch to the project we want to unlock
    Set Application.VBE.ActiveVBProject = Project
    If Not Application.VBE.ActiveVBProject Is Project Then GoTo ErrorHandler

    ' Launch the menu item Tools -> VBA Project Properties
    ' This will trigger the password dialog
    ' which will then get picked up by the callback
    Application.VBE.CommandBars.FindControl(ID:=2578).Execute

    ' Loop until callback procedure 'UnlockTimerProc' has run
    ' determine run by watching the state of the global variable 'g_result'
    ' ... or backstop of 2 seconds max
    timeout = Now() + TimeSerial(0, 0, TimeoutSecond)
    Do While g_Result = 0 And Now() < timeout
        DoEvents
    Loop
    If g_Result Then UnlockProject = 0

ErrorHandler:
    ' Switch back to the Excel application
    AppActivate Application.Caption

    ' Unfreeze window updates
    LockWindowUpdate 0

End Function

#If VBA7 Then
    Private Function UnlockTimerProc(ByVal hWnd As LongPtr, ByVal uMsg As Long, ByVal idEvent As LongPtr, ByVal dwTime As Long) As Long
#Else
    Private Function UnlockTimerProc(ByVal hWnd As Long, ByVal uMsg As Long, ByVal idEvent As Long, ByVal dwTime As Long) As Long
#End If

#If VBA7 Then
    Dim hWndPassword As LongPtr
    Dim hWndOK As LongPtr
    Dim hWndTmp As LongPtr
    Dim lRet As LongPtr
#Else
    Dim hWndPassword As Long
    Dim hWndOK As Long
    Dim hWndTmp As Long
    Dim lRet As Long
#End If
Dim lRet2 As Long
Dim sCaption As String
Dim timeout As Date
Dim timeout2 As Date
Dim pwd As String

    ' Protect ourselves against failure :)
    On Error GoTo ErrorHandler

    ' Kill timer used to initiate this callback
    KillTimer 0, idEvent

    ' Determine the Title for the password dialog
    Select Case Application.LanguageSettings.LanguageID(msoLanguageIDUI)
        ' For the japanese version
        Case 1041
            sCaption = ChrW(&H30D7) & ChrW(&H30ED) & ChrW(&H30B8) & _
                        ChrW(&H30A7) & ChrW(&H30AF) & ChrW(&H30C8) & _
                        ChrW(&H20) & ChrW(&H30D7) & ChrW(&H30ED) & _
                        ChrW(&H30D1) & ChrW(&H30C6) & ChrW(&H30A3)
        Case Else
            sCaption = " Password"
    End Select
    sCaption = g_ProjectName & sCaption

    ' Set a max timeout of 2 seconds to guard against endless loop failure
    timeout = Now() + TimeSerial(0, 0, TimeoutSecond)
    Do While Now() < timeout

        hWndPassword = 0
        hWndOK = 0
        hWndTmp = 0

        ' Loop until find a window with the correct title that is a child of the
        ' VBE handle for the project to unlock we found in 'UnlockProject'
        Do
            hWndTmp = FindWindowEx(0, hWndTmp, vbNullString, sCaption)
            If hWndTmp = 0 Then Exit Do
        Loop Until GetParent(hWndTmp) = g_hwndVBE

        ' If we don't find it then could be that the calling routine hasn't yet triggered
        ' the appearance of the dialog box
        ' Skip to the end of the loop, wait 0.1 secs and try again
        If hWndTmp = 0 Then GoTo Continue

        ' Found the dialog box, make sure it has focus
        Debug.Print "found window"
        lRet2 = SendMessage(hWndTmp, TCM_SETCURFOCUS, 1, ByVal 0&)

        ' Get the handle for the password input
        hWndPassword = GetDlgItem(hWndTmp, IDPassword)
        Debug.Print "hwndpassword: " & hWndPassword

        ' Get the handle for the OK button
        hWndOK = GetDlgItem(hWndTmp, IDOK)
        Debug.Print "hwndOK: " & hWndOK

        ' If either handle is zero then we have an issue
        ' Skip to the end of the loop, wait 0.1 secs and try again
        If (hWndTmp And hWndOK) = 0 Then GoTo Continue

        ' Enter the password ionto the password box
        lRet = SetFocusAPI(hWndPassword)
        lRet2 = SendMessage(hWndPassword, EM_SETSEL, 0, ByVal -1&)
        lRet2 = SendMessage(hWndPassword, EM_REPLACESEL, 0, ByVal g_Password)

        ' As a check, get the text back out of the pasword box and verify it's the same
        pwd = String(260, Chr(0))
        lRet2 = SendMessage(hWndPassword, WM_GETTEXT, Len(pwd), ByVal pwd)
        pwd = Left(pwd, InStr(1, pwd, Chr(0), 0) - 1)
        ' If not the same then we have an issue
        ' Skip to the end of the loop, wait 0.1 secs and try again
        If pwd <> g_Password Then GoTo Continue

        ' Now we need to close the Project Properties window we opened to trigger
        ' the password input in the first place
        ' Like the current routine, do it as a callback
        lRet = SetTimer(0, 0, 100, AddressOf ClosePropertiesWindow)

        ' Click the OK button
        lRet = SetFocusAPI(hWndOK)
        lRet2 = SendMessage(hWndOK, BM_CLICK, 0, ByVal 0&)

        ' Set the gloabal variable to success to flag back up to the initiating routine
        ' that this worked
        g_Result = 1
        Exit Do

        ' If we get here then something didn't work above
        ' Wait 0.1 secs and try again
        ' Master loop is capped with a longstop of 2 secs to terminate endless loops
Continue:
        DoEvents
        Sleep 100
    Loop
    Exit Function

    ' If we get here something went wrong so close the password dialog box (if we have a handle)
    ' and unfreeze window updates (if we set that in the first place)
ErrorHandler:
    Debug.Print Err.Number
    If hWndPassword <> 0 Then SendMessage hWndPassword, WM_CLOSE, 0, ByVal 0&
    LockWindowUpdate 0

End Function

#If VBA7 Then
    Function ClosePropertiesWindow(ByVal hWnd As LongPtr, ByVal uMsg As Long, ByVal idEvent As LongPtr, ByVal dwTime As Long) As Long
#Else
    Function ClosePropertiesWindow(ByVal hWnd As Long, ByVal uMsg As Long, ByVal idEvent As Long, ByVal dwTime As Long) As Long
#End If

#If VBA7 Then
    Dim hWndTmp As LongPtr
    Dim hWndOK As LongPtr
    Dim lRet As LongPtr
#Else
    Dim hWndTmp As Long
    Dim hWndOK As Long
    Dim lRet As Long
#End If
Dim lRet2 As Long
Dim timeout As Date
Dim sCaption As String

    ' Protect ourselves against failure :)
    On Error GoTo ErrorHandler

    ' Kill timer used to initiate this callback
    KillTimer 0, idEvent

    ' Determine the Title for the project properties dialog
    sCaption = g_ProjectName & " - Project Properties"
    Debug.Print sCaption

    ' Set a max timeout of 2 seconds to guard against endless loop failure
    timeout = Now() + TimeSerial(0, 0, TimeoutSecond)
    Do While Now() < timeout

        hWndTmp = 0

        ' Loop until find a window with the correct title that is a child of the
        ' VBE handle for the project to unlock we found in 'UnlockProject'
        Do
            hWndTmp = FindWindowEx(0, hWndTmp, vbNullString, sCaption)
            If hWndTmp = 0 Then Exit Do
        Loop Until GetParent(hWndTmp) = g_hwndVBE

        ' If we don't find it then could be that the calling routine hasn't yet triggered
        ' the appearance of the dialog box
        ' Skip to the end of the loop, wait 0.1 secs and try again
        If hWndTmp = 0 Then GoTo Continue

        ' Found the dialog box, make sure it has focus
        Debug.Print "found properties window"
        lRet2 = SendMessage(hWndTmp, TCM_SETCURFOCUS, 1, ByVal 0&)

        ' Get the handle for the OK button
        hWndOK = GetDlgItem(hWndTmp, IDOK)
        Debug.Print "hwndOK: " & hWndOK

        ' If either handle is zero then we have an issue
        ' Skip to the end of the loop, wait 0.1 secs and try again
        If (hWndTmp And hWndOK) = 0 Then GoTo Continue

        ' Click the OK button
        lRet = SetFocusAPI(hWndOK)
        lRet2 = SendMessage(hWndOK, BM_CLICK, 0, ByVal 0&)

        ' Set the gloabal variable to success to flag back up to the initiating routine
        ' that this worked
        g_Result = 1
        Exit Do

        ' If we get here then something didn't work above
        ' Wait 0.1 secs and try again
        ' Master loop is capped with a longstop of 2 secs to terminate endless loops
Continue:
        DoEvents
        Sleep 100
    Loop
    Exit Function

    ' If we get here something went wrong so unfreeze window updates (if we set that in the first place)
ErrorHandler:
    Debug.Print Err.Number
    LockWindowUpdate 0

End Function

@James Macadie的答案（上图）是我找到的最好的（我正在运行32位Excel 365/2019）

注意：我发现你必须有Application.ScreenUpdating = True才能通过不同的sub或函数调用James的方法，否则你可能会得到Invalid procedure call or argument错误（如果在调试模式之外运行）。

此解决方案似乎上级以下两种解决方案：

1. http://www.siddharthrout.com/index.php/2019/01/20/unprotect-vbproject-from-vb-code/.创建一个单独的Excel应用程序示例来运行解锁过程，这在我的用例中不起作用
2. https://www.mrexcel.com/board/threads/lock-unlock-vbaprojects-programmatically-without-sendkeys.1136415/. unstable，如果对多个工作簿顺序运行，会失败，我认为是由于James的解决方案中缺少计时器/等待循环实现的原因-我没有彻底调试这个问题

对James MacAdie的奇妙解决方案的修改建议：
在Function UnlockTimerProc中，将代码pwd = Left(pwd, ...替换为pwd = VBA.Left(pwd, ...，否则它会在某些书籍中失败，这是我很难弄清楚的。谢谢。问候。