怎么调用API?

[coolbye]

ZeroMemory(lpDest as Any, byval nNum as Long)

Dim a(1) as Byte
ZeroMemory a(0), 1

执行后非法操作，不知要怎么用
Any要怎么调

[rappercn]

Private Declare Sub FillMemory Lib "kernel32.dll" Alias "RtlFillMemory" (Destination As Any, ByVal Length As Long, ByVal Fill As Byte)
Private Declare Sub ZeroMemory Lib "kernel32.dll" Alias "RtlZeroMemory" (Destination As Any, ByVal Length As Long)
Private Sub Form_Load()
Dim TestString As String
'Mak sure Visual Basic repaint the form automatically
Me.AutoRedraw = True
'Create a buffer string
TestString = String(25, "X")
Me.Print "This is our initial string: " + TestString
'Fill the buffer-string with A's
FillMemory ByVal TestString, Len(TestString), Asc("A")
Me.Print "This is our string after FillMemory: " + TestString
'Empty the string
ZeroMemory ByVal TestString, Len(TestString)
Me.Print "This is our string after ZeroMemory: " + TestString
End Sub

[of123]

Public Declare Sub ZeroMemory Lib "KERNEL32" Alias "RtlMoveMemory" (dest As Any, ByVal numBytes As Long)

Dim CurrChars(0 To 255) As Byte
Call ZeroMemory(CurrChars(0), 256 * Len(CurrChars(0)))

[coolbye]

我这样
dim astring as string
astring = "A"
ZeroMemory byval astring, len(astring)

也不行,错在哪

[of123]

Dim strTmp As String * 256
ZeroMemory strTmp, Len(strTmp)

[coolbye]

astring = "A"
不是已经有一个字节的空间吗?