取得TextBox某一行的字串

這是使用EM_GETLINE message來做，比較奇特的是lParam是指向一個字串所在的位置，但是該字串傳入時，前兩個Byte要存該字串允許的最大長度。

'以下在Form需一個TextBox，並設定MultiLine = True, 一個Command Button
Private Sub Command1_Click()
Dim str5 As String
str5 = GetaLine(Text1,1)　'取得第二行的字串，以0為基底
End Sub
'以下在.Bas
Option Explicit
Const EM_GETLINE = &HC4
Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
　　　　 (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _
　　　　 lParam As Any) As Long
Public Function GetaLine(Text1 As TextBox, ByVal ntx As Long) As String
Dim str5(255) As Byte '如果您的字串 > 255 byte請自行增加該Byte Array
Dim str6 As String, i As Long
str5(0) = 255 '字串的前兩個Byte存該字串的最大長度
str5(0) = 255
i = SendMessage(Text1.hwnd, EM_GETLINE, ntx, str5(0))
If i = 0 Then
　　 GetaLine = ""
Else
　　 str6 = StrConv(str5, vbUnicode)
　　 GetaLine = Left(str6, InStr(1, str6, Chr(0)) - 1)
End If
End Function