vb读取text 行并做对比的问题

Private Const EM_GETLINE = &HC4
Private Const EM_LINELENGTH = &HC1
Private Const EM_LINEINDEX = &HBB
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
Private Declare Sub RtlMoveMemory Lib "KERNEL32" (lpvDest As Any, lpvSource As Any, ByVal cbCopy As Long)

Sub TB_GetLine(ByVal hWnd As Long, ByVal whichLine As Long, Line As String)

Dim length As Long, bArr() As Byte, bArr2() As Byte, lc As Long
lc = SendMessage(hWnd, EM_LINEINDEX, whichLine, ByVal 0&)
length = SendMessage(hWnd, EM_LINELENGTH, lc, ByVal 0&)
If length > 0 Then
ReDim bArr(length + 1) As Byte, bArr2(length - 1) As Byte
Call RtlMoveMemory(bArr(0), length, 2) '准备一个存储器，传递消息之前先在存储器的前两个字节填入存储器的长度
Call SendMessage(hWnd, EM_GETLINE, whichLine, bArr(0))
Call RtlMoveMemory(bArr2(0), bArr(0), length)
Line = S