Visual Basic Programming Code Examples

Visual Basic > Forms Code Examples

Controlling the scrolling of a textbox



Controlling the scrolling of a textbox

The following code shows how to scroll a multiline text box both horizontally and vertically.

Option Explicit

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Integer, ByVal lParam As Long) As Long

'Purpose     :  Scrolls a Multiline textbox horizontally
'Inputs      :  lhwndTextbox                The handle to the textbox.
'               [bScrollRight]              If True scrolls to the right, else scrolls left.
'               [lNumCharacters]            The number of characters to scroll.
'Outputs     :  Returns non zero number on success.
'Notes       :  The .ScrollBars property must include a horizontal scroll bar.
'Revisions   :

Function TextBoxHorizontalScroll(lhwndTextbox As Long, Optional bScrollRight As Boolean = True, Optional lNumCharacters As Long = 1) As Long
    Const SB_LINERIGHT = 1, SB_LINELEFT = 0, WM_HSCROLL = &H114
    Dim lThisCharacters  As Long
    
    If bScrollRight Then
        For lThisCharacters = 1 To lNumCharacters
            TextBoxHorizontalScroll = SendMessage(lhwndTextbox, WM_HSCROLL, SB_LINERIGHT, ByVal 0&)
        Next
    Else
        For lThisCharacters = 1 To lNumCharacters
            TextBoxHorizontalScroll = SendMessage(lhwndTextbox, WM_HSCROLL, SB_LINELEFT, ByVal 0&)
        Next
    End If
End Function


'Purpose     :  Scrolls a Multiline textbox vertically
'Inputs      :  lhwndTextbox                The handle to the textbox.
'               [bScrollUp]                 If True scrolls upwards, else scrolls downwards.
'               [lNumCharacters]            The number of characters to scroll.
'Outputs     :  Returns non zero number on success.
'Notes       :  The .ScrollBars property must include a vertical scroll bar.
'Revisions   :

Function TextBoxVerticalScroll(lhwndTextbox As Long, Optional bScrollUp As Boolean = True, Optional lNumCharacters As Long = 1) As Long
    Const SB_LINEUP = 0, SB_LINEDOWN = 1, WM_VSCROLL = &H115
    Dim lThisCharacters  As Long
    
    If bScrollUp Then
        For lThisCharacters = 1 To lNumCharacters
            TextBoxVerticalScroll = SendMessage(lhwndTextbox, WM_VSCROLL, SB_LINEUP, ByVal 0&)
        Next
    Else
        For lThisCharacters = 1 To lNumCharacters
            TextBoxVerticalScroll = SendMessage(lhwndTextbox, WM_VSCROLL, SB_LINEDOWN, ByVal 0&)
        Next
    End If
End Function


'Demonstration code
Private Sub Command1_Click()
    'Move 5 characters left
    TextBoxHorizontalScroll Me.Text1.hwnd, False, 5
End Sub

Private Sub Command2_Click()
    'Move 5 characters right
    TextBoxHorizontalScroll Me.Text1.hwnd, True, 5
End Sub