TIP: Append to TextBox with AutoScroll to End-of-Text...

[(X)]

I found code that positions the cursor in a multi-line TextBox to the end-of-text and simultaneously brings the end-of-text into view.  This way you can have the effect of a down scrolling cursor terminal screen.

See following posts for an even better way...

Visual Basic seems to have this covered with a <textbox>.AppendText() command.

This is the key piece of code I found.  The first line sets the focus to the specified text box control and the second sends a Ctrl-End key sequence which positions the cursor to the end-of-text and brings it into view.

<editbox>.SetFocus
SendKeys "^{END}", True



I suppose one could create a procedure called AppendText()...


Proc AppendText(tb As TextBox, s$)

''''''''''''''''''''''''''''''''''''''''''''''''''
' Append text to specified multi-line textbox
' control and automatically bring the appended
' text into view.
'
tb.SetFocus
tb.text = tb.text & s$
SendKeys "^{END}", True

EndProc

[dragonjim]

Nice tip.

Another way of doing this is to use the ScrollCaret method as below

Ocx TextBox tb = "", 10, 10, 400, 40 : tb.MultiLine = True : tb.ScrollBars = 2
tb.Text = "Really long"
Do
 tb.Text = tb.Text & "and still longer..."
Until Len(tb.Text) > 400
tb.Text = tb.Text & " and the caret should appear here--->"
tb.SelStart = Len(tb.Text)
tb.ScrollCaret
tb.SetFocus
Do : Sleep : Until Me Is Nothing

You should also be able to use the Scroll(RowFromChar,ColFromChar) method but, for some reason, the RowFromChar and ColFromChar both return -1 if the caret position is at the end of the text...will have to look into this to see if this is expected behaviour.

[(X)]

Thanks dragonjim!,

This is "ACE"!

I've changed AppendText() to:

Proc P_AppendText(tb As TextBox, s$)
 
 ''''''''''''''''''''''''''''''''''''''''''''''''''
 ' Append text to specified multi-line textbox
 ' control and automatically bring the appended
 ' text into view.
 '
 tb.SetFocus
 tb.Text = tb.Text & s$
 tb.SelStart = Len(tb.Text)
 tb.SelLength = 0
 tb.ScrollCaret
 
EndProc

This method: <object>.ScrollCaret conveniently avoids triggering a KeyDown event.

A keyboard input event seems to be triggered by every SendKeys "^{END}", True command which may for instance interfere with handling of the user keypress events.

[dragonjim]

You should also be able to use the Scroll(RowFromChar,ColFromChar) method but, for some reason, the RowFromChar and ColFromChar both return -1 if the caret position is at the end of the text...will have to look into this to see if this is expected behaviour.

It appears that RowFromChar and ColFromChar are broken, mainly because the underlying message call using EM_POSFROMCHAR seems not to work as described for textboxes; not only do you get -1 returned if the caret is at the end of the text, but the y-value seems to go no higher than 182. I get the same issues with the User32 library function GetCaretPos.

Hence, I think it is safe to say that RowFromChar and ColFromChar are broken for Textboxes and have only limited use with RichEdit controls.

[(X)]

This (taken from GFA Help document) seems to work...

$Library "gfawinx"
$Library "UpdateRT"
UpdateRuntime      ' Patches GfaWin23.Ocx

OpenW 1

Ocx TextBox tb = "", 10, 10, 300, 300 : .MultiLine = True : .ScrollBars = 2 : .BorderStyle = 1

Global Int32 n, tbpos

For n = 0 To Screen.FontCount - 1
 tb.Text = tb.Text & Screen.Fonts(n) & ", "
Next n

Ocx Command cmd(1) = "Scroll Up", 320, 10, 100, 22
Ocx Command cmd(3) = "Scroll Down", 320, 40, 100, 22
Ocx Command cmd(4) = "Scroll to Caret", 320, 70, 100, 22

Do : Sleep : Until Win_1 Is Nothing

Sub cmd_Click(Index%)
 tb.SetFocus
 If Index% = 4 Then tb.ScrollCaret : Exit Sub
 ~tb.Scroll(0, (Index% - 2) * 3)
EndSub

Sub tb_GotFocus
 tb.SelStart = tbpos
EndSub

Sub tb_LostFocus
 If Not tb Is Nothing Then tbpos = tb.SelStart
EndSub


[dragonjim]

That will teach me to read the help file properly especially as I wrote that example years ago...

In that case, to answer your original query and without having to move the caret, the following code should scroll to the bottom of a textbox:

OpenW 1
Ocx TextBox tb = "", 10, 10, 300, 300 : .MultiLine = True : .ScrollBars = 2 : .BorderStyle = 1
Global Int32 n, tbpos

For n = 0 To Screen.FontCount - 1
 tb.Text = tb.Text & Screen.Fonts(n) & ", "
Next n

Ocx Command cmd = "Scroll to End", 320, 70, 100, 22

Do : Sleep : Until Win_1 Is Nothing

Sub cmd_Click
 tb.SetFocus
 Local caretline% = tb.LineFromChar(tb.SelStart)               // Line currently containing the caret
 Local lastline% = tb.LineFromChar(Len(tb.Text))               // The number of the last line of text
 Local firstchar% = tb.CharFromLine(Len(tb.Text))              // First character in the last line of text
 Local lastchar% = Len(tb.Text)                                // Last charcter in the last line of text
 ~tb.Scroll(lastchar% - firstchar% + 1, lastline% - caretline% + 1)
EndSub

Sub tb_GotFocus
 tb.SelStart = tbpos
EndSub

Sub tb_LostFocus
 If Not tb Is Nothing Then tbpos = tb.SelStart
EndSub

The code to scroll horizontally may seem redundant but would come in useful if there was a horizontal scroll bar as well.