You can make an Array of TextBoxes and use the GetKeyState API to determine if they were pressed.

Code:
Private Declare Function GetKeyState Lib "user32" (ByVal nVirtKey As Long) As Integer

Private Sub Text1_KeyDown(Index As Integer, KeyCode As Integer, Shift As Integer)

    'If Control and C are pressed then
    If GetKeyState(vbKeyControl) And GetKeyState(vbKeyC) Then
        MsgBox ("Control + C was pressed")
    End If
        
End Sub