How to do Ctrl + Z?

  • Thread starter Thread starter Mr. B
  • Start date Start date
M

Mr. B

In VB.net, you can Copy to Clipboard... and then Paste from Clipboard.

What I'd like to do is to do a CTRL + Z to do and 'undo'.

For example, if you have some date in Combobox1 and Copy it to Clipboard. You
can then Paste it to Combobox2. But in Combobox2, you can (via keyboard)
CTRL+Z and undo the paste.

How can you in VB.net?

Thanks

Bruce
 
Hi Bruce,

Undo and Redo need a context. ComboBoxes and TextBoxes, etc - they all
have an Undo because editable controls do that kind of thing.

What do you want your Undo/Redo to work with?

The most general answer is that you must save the state of something before
an operation and swap the states when Undo is requested. (Swap - so that Undo
can undo the Undo). Multiple Undo requires the management of a stack of Undo
states.

Regards,
Fergus
 
* Mr. B said:
In VB.net, you can Copy to Clipboard... and then Paste from Clipboard.

What I'd like to do is to do a CTRL + Z to do and 'undo'.

For example, if you have some date in Combobox1 and Copy it to Clipboard. You
can then Paste it to Combobox2. But in Combobox2, you can (via keyboard)
CTRL+Z and undo the paste.
Click to expand...

In your own control? In your own form? You can define a menu with
theshowtcuts, like in:

<http://www.mvps.org/dotnet/dotnet/samples/controls/downloads/RichTextBoxContext.zip>
 
Fergus Cooney said:
Hi Bruce,
Click to expand...

Hullo Fergus.
What do you want your Undo/Redo to work with?
Click to expand...

I sort of mentioned it in my original post. But here it is again:

You have a Combobox1 with some Text. A user cuts and pastes it into a 2nd
Combobox (2). Then they think.. hmmm... don't want to do that. So an 'undo'
would be nice.

Now... you can do the undo manually via the keyboard (CTRL+Z). Which is
really nothing more than the standard CTRL+Z that you can do in Windows (ie:
delete a file in File Explorer... press CTRL+Z and it will be restored from
Trashcan).
The most general answer is that you must save the state of something before
an operation and swap the states when Undo is requested. (Swap - so that Undo
can undo the Undo). Multiple Undo requires the management of a stack of Undo
Click to expand...

Yeah. I was just hoping that an easier way was available. No big deal. Not
critical for my app... just was a thought.

Thanks!

Bruce
 
Hi Bruce,

You said it's not important - so don't answer if you don't want, but...

|| You have a Combobox1 with some Text. A user cuts and pastes it
|| into a 2nd Combobox (2). Then they think.. hmmm... don't want to
|| do that. So an 'undo' would be nice.
||
|| Now... you can do the undo manually via the keyboard (CTRL+Z).
|| Which is really nothing more than the standard CTRL+Z that you can
|| do in Windows

Like you say, you mentioned it in both posts, but what you've mentioned
is what already happens. Which is why I asked 'what do <you> want to do?'

In other words what are you going to be undoing and redoing? - because
the ComboBox one is already covered by Ctrl-Z, how can you improve it?

I'm just curious. ;-) (and I'm surely missing something).

Regards,
Fergus
 
Fergus Cooney said:
Hi Bruce,

You said it's not important - so don't answer if you don't want, but...
Click to expand...
In other words what are you going to be undoing and redoing? - because
the ComboBox one is already covered by Ctrl-Z, how can you improve it?
Click to expand...

Because... not all Users are that smart (um... I mean... knowledgeable). And
(at least where I work) not many even 'know' about CTRL+Z... much less CTRL+C
or CTRL+V (grin)

So I'm working on the "make it damn Idiot proof" kinda level (:

So having 3 buttons for each (C, V, Z) is the target.

Regards,

Bruce
 
Hi Bruce,

Now I'm with you! :-)

One option is to put focus back to the Control and then
send it the appropriate key using SendKeys.

Regards,
Fergus
 
* "Mr. B said:
Because... not all Users are that smart (um... I mean... knowledgeable). And
(at least where I work) not many even 'know' about CTRL+Z... much less CTRL+C
or CTRL+V (grin)

So I'm working on the "make it damn Idiot proof" kinda level (:

So having 3 buttons for each (C, V, Z) is the target.
Click to expand...

You may want to grab the handle of the textbox contained in the combobox and
use pinvoke on 'SendMessage' + 'EM_UNDO' and 'EM_REDO' (all code below
untested).

\\\
Public Const EM_UNDO As Int32 = &HC7
Public Const EM_REDO As Int32 = &HC7
///

You can use something like this to get the handle of the edit protion of the
combobox:

\\\
Private Declare Auto Function GetWindow Lib "user32.dll" ( _
ByVal hwnd As IntPtr, _
ByVal wCmd As Int32 _
) As IntPtr

Private Declare Auto Function SendMessage Lib "user32.dll" ( _
ByVal hwnd As IntPtr, _
ByVal wMsg As Int32, _
ByVal wParam As Int32, _
ByVal lParam As Int32 _
) As Int32

Private Const EM_SETPASSWORDCHAR As Int32 = &HCC

Private Const GW_CHILD As Int32 = 5

Private Sub Form1_Load( _
ByVal sender As System.Object, _
ByVal e As System.EventArgs _
) Handles MyBase.Load
SendMessage( _
GetWindow( _
Me.ComboBox1.Handle, _
GW_CHILD _
), _
EM_SETPASSWORDCHAR, _
Asc("*"c), _
0 _
)
Me.ComboBox1.Refresh()
End Sub
///
 
Herfried K. Wagner said:
You may want to grab the handle of the textbox contained in the combobox and
use pinvoke on 'SendMessage' + 'EM_UNDO' and 'EM_REDO' (all code below
untested).
Click to expand...

Ouch! So many 'complicated' ways :(

But many Thanks! At least I've got something to take off from

Regards,

Bruce
 
Hi Mr B,

I thought I'd test it just in case.

Private Sub btnUndo_Click (sender As Object, e As System.EventArgs) _
Handles btnUndo.Click
ComboBox1.Focus
SendKeys.Send ("^Z")
End Sub

Regards,
Fergus

--
=================================================
Thought for the day:
Have you noticed how condescending Herfried can be?

=================================================

(There's a feud going on)
 
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