Option Explicit

Private Declare Function AttachThreadInput Lib "user32" (ByVal idAttach As Long, ByVal idAttachTo As Long, ByVal fAttach As Long) As Long

Private Declare Function GetWindowThreadProcessId Lib "user32" (ByVal Hwnd As Long, lpdwProcessId As Long) As Long

Private Declare Function GetForegroundWindow Lib "user32" () As Long

Private Declare Function GetFocus Lib "user32" () As Long

'----------------------------------------------------
'获取当前控件句柄
'----------------------------------------------------
'备注：
'----------------------------------------------------
Public Function GetHwnd() As Long
    Dim Hwnd As Long
    Dim PID As Long
    Dim TID As Long
    Dim hWndFocus As Long
            
    Hwnd = GetForegroundWindow
    
    If Hwnd Then
    
        TID = GetWindowThreadProcessId(Hwnd, PID)
        
        AttachThreadInput App.ThreadID, TID, True
        
        GetHwnd = GetFocus
        
        AttachThreadInput App.ThreadID, TID, False

    End If
    
End Function

------------------------------获取当前鼠标所在Hwnd

Option Explicit

Private Type POINTAPI

        X   As Long

        Y   As Long

End Type

Private Declare Function GetCursorPos Lib "user32 " (lpPoint As POINTAPI) As Long

Private Declare Function WindowFromPoint Lib "user32 " (ByVal xPoint As Long, ByVal yPoint As Long) As Long

Private Sub Timer1_Timer()

        Dim P     As POINTAPI, h       As Long

        '获取鼠标当前位置的坐标，以屏幕为坐标系

        GetCursorPos P

        '获取当前鼠标所在点所属窗口（控件）的句柄

        Text1 = WindowFromPoint(P.X, P.Y)

End Sub