Caret on left side of selected text in textbox

[Ulrich Sprick]

Hi all,

how can select some text in the textbox, but have the caret on the LEFT side of the selection? You can do that with the mouse by
drawing the mouse cursor from right to left over some text. But how can it be done programmatically?

I played around with textbox.SelectionStart and .SelectionLength, and .Select(pos, len), but negative values for SelectionLength
throw an exception. Do I have to send a WM_ or EM_ message to the window handle?

Thanks in advance,
ulrich

 

[Herfried K. Wagner [MVP]]

Hello,

how can select some text in the textbox, but have the caret
on the LEFT side of the selection? You can do that with
the mouse by drawing the mouse cursor from right to left
over some text. But how can it be done programmatically?

Quick and *very* dirty:

\\\
Me.TextBox1.Focus()
Me.TextBox1.SelectionStart = 6
Me.TextBox1.SelectionLength = 0
SendKeys.Send("+{LEFT 4}")
///

 

[Ulrich Sprick]

Works! Great! Thanks!
ulli

Hello,



Quick and *very* dirty:

\\\
Me.TextBox1.Focus()
Me.TextBox1.SelectionStart = 6
Me.TextBox1.SelectionLength = 0
SendKeys.Send("+{LEFT 4}")
///

 

[Ulrich Sprick]

Hi Herfried,

w32api.SendMessage( this.TextBox1.Handle, (int)w32api.EditControlMsg.EM_SETSEL, 7, 3 );

should place the "anchor point" at pos 7 and the caret at pos 3, according to the W32 SDK, but either the this wrong or the DotNET
framework adds another level of logik to the framework textbox: The caret is still on the right hand side of the selection.

Thus, your hack seems to be the only working solution.
Thanks,
ulli

 

[Kevin Westhead]

w32api.SendMessage( this.TextBox1.Handle,

(int)w32api.EditControlMsg.EM_SETSEL, 7, 3 );

should place the "anchor point" at pos 7 and the caret at pos 3, according

to the W32 SDK, but either the this wrong or the DotNET

framework adds another level of logik to the framework textbox: The caret

is still on the right hand side of the selection.


You could try using EM_POSFROMCHAR to get the x/y location of a specified
character index and then use SetCaretPos to move the caret to that position.
SetCaretPos might require some PointToClient or PointToScreen conversions,
but I've never used this function so I can't say for sure.

 

[Ulrich Sprick]

Hi Kevin,
the documentation for SetCaretPos() doesn't make statements regarding side effects on the selected text, so this might work. I'll
give it a try and post the results here (in a few days).
Thank you,
ulli

 

[Kevin Westhead]

the documentation for SetCaretPos() doesn't make statements regarding side

effects on the selected text, so this might work. I'll

give it a try and post the results here (in a few days).

You're right of course, changing the caret position could clear the
selection. I guess there's only one way to find out. <g>