VB - Limit TextBox Line Length

[The Hobo]

Someone asked once if it would be possible to limit the length of each line in a text box to 10 characters. This is the code I came up with:

Option Explicit
 
'API Declarations:
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
 
'Constant Delcarations
Private Const EM_LINEINDEX = &HBB
Private Const EM_LINELENGTH = &HC1
 
Private Sub Text1_KeyPress(KeyAscii As Integer)
Dim lLen As Long
 
  'Get the length of the current line:
  lLen = SendMessage(Text1.hwnd, EM_LINELENGTH, EM_LINEINDEX, 0&)
  
  'If length is 10, don't allow more characters:
  If lLen = 10 And KeyAscii <> vbKeyReturn And KeyAscii <> vbKeyBack Then
      KeyAscii = 0
  End If
  
End Sub

[seec77]

or you can just do this:

Text1.MaxLen = 10

a bit simpler

[crptcblade]

Originally posted by seec77
or you can just do this:

Text1.MaxLen = 10

a bit simpler

Well, first, its MaxLength .

Second, that will limit the size of the whole textbox. Hobo's way, I believe, works on a line by line basis.

[The Hobo]

Originally posted by crptcblade
Second, that will limit the size of the whole textbox. Hobo's way, I believe, works on a line by line basis.

Yes, indeedy.

I don't know why you'd want such a thing, but I figured since one person asked, others may as well.

[seec77]

whoops...
sorry, thought it was just for the whole textbox... anyway, sorry again...

[brandoom]

Great Code!

One issue:

I modified the code so that when the line reaches a certain length (10 for this example), text1.text = text1.text & VBCRLF so that the new text starts on the next line. If i then go back up to the previous line, I can type the 11th character and keep typing past the original 10 characters. Is there any way to prevent this?

Originally posted by The Hobo
Someone asked once if it would be possible to limit the length of each line in a text box to 10 characters. This is the code I came up with:

Option Explicit
 
'API Declarations:
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
 
'Constant Delcarations
Private Const EM_LINEINDEX = &HBB
Private Const EM_LINELENGTH = &HC1
 
Private Sub Text1_KeyPress(KeyAscii As Integer)
Dim lLen As Long
 
  'Get the length of the current line:
  lLen = SendMessage(Text1.hwnd, EM_LINELENGTH, EM_LINEINDEX, 0&)
  
  'If length is 10, don't allow more characters:
  If lLen = 10 And KeyAscii <> vbKeyReturn And KeyAscii <> vbKeyBack Then
      KeyAscii = 0
  End If
  
End Sub