Vilhelm-Ion Praisach: august 2017

marți, 22 august 2017

Easter eggs (4)

I found a pattern. The keys that are grouped ("neighbors") behaves similarly, especially those in the median part and the right part of the alphanumeric region. I mean it's difficult to catch three of them pressed simultaneously. Any combination of two, or two + other key shows no problem.

Using an US keyboard, the alphanumeric region
4 5 6 7
E R T Y U
D F G H J K
C V B N M ,

0 - = (zero, minus, equal)
P [ ]
L ; '

The numeric keypad
/ * -
0 . 2
0 . 3
1 2 4
1 2 5
2 4 5
a.s.o

The test code used by me (click or press the command button to experiment different combinations):

CLEAR

PUBLIC ofrm

ofrm = CREATEOBJECT("myform")

ofrm.show()

DEFINE CLASS myform as form

Autocenter = .T.

l1 = .F. && .T. while key #1 is pressed

l2 = .F. && .T. while key #2 is pressed

l3 = .F. && .T. while key #3 is pressed

ln1 = -1 && Store scan code 1

ln2 = -1 && Store scan code 2

ln3 = -1 && Store scan code 3

ADD OBJECT txt1 as textbox

ADD OBJECT cmd as commandbutton WITH top = 50, caption = "Reset" && reset the combination

PROCEDURE init

UNBINDEVENTS(This.hwnd)

BINDEVENT(This.hwnd,0x0100,This,"detectkeydown")

BINDEVENT(This.hwnd,0x0101,This,"detectkeyup")

ENDPROC

PROCEDURE detectkeydown

LPARAMETERS p1,p2,p3,p4

* p3 = Virtual-key code

IF This.ln3 = -1 AND !INLIST(This.ln1, -1, m.p3) AND !INLIST(This.ln2, -1, m.p3)

This.ln3 = m.p3

ENDIF

IF m.p3 = This.ln3

This.l3 = .T.

ENDIF

IF This.ln2 = -1 AND !INLIST(This.ln1, -1, m.p3)

This.ln2 = m.p3

ENDIF

IF m.p3 = This.ln2

This.l2 = .T.

ENDIF

IF This.ln1 = -1

This.ln1 = m.p3

ENDIF

IF m.p3 = This.ln1

This.l1 = .T.

ENDIF

ACTIVATE SCREEN

? m.p3

IF This.l1 AND This.l2 AND This.l3

? 'Bingo!'

? 'An ' + LTRIM(STR(This.ln1)) + '+' + LTRIM(STR(This.ln2)) + '+' + LTRIM(STR(This.ln3)) + ' occures'

ENDIF

ACTIVATE SCREEN

?This.l1 ,This.l2 ,This.l3

ENDPROC

PROCEDURE detectkeyup

LPARAMETERS p1,p2,p3,p4

* p3 = Virtual-key code

IF p3 = This.ln1

This.l1 = .F.

ENDIF

IF p3 = This.ln2

This.l2 = .F.

ENDIF

IF p3 = This.ln3

This.l3 = .F.

ENDIF

ENDPROC

PROCEDURE cmd.click

STORE -1 TO ThisForm.ln1, ThisForm.ln2, ThisForm.ln3

STORE .F. TO ThisForm.l1, ThisForm.l2, ThisForm.l3

ENDPROC

ENDDEFINE

Update
The previous test was on a Dell keyboard with a US layout (Windows 7 32 bit).
I repeated the same test, but this time using a Fujitsu keyboard with a German layout (Windows 10 prof 64 bit). And what do you know? I managed to catch a 3+4+5. Not easy, but Bingo!
The patterns are almost the same.
Ha! So most probably it's a hardware issue.

Later
A new test using a Genius keyboard (Windows 10 home 32 bit), with an US layout, behaves poorly.
Another test. A HP notebook (Windows 10 home 64 bit) with a Germanic layout, behaves even better than Fujitsu.
A final test using a Lenovo laptop (Windows 10 home 64 bit) with an US layout, behaves poorly.

Again
This article https://en.wikipedia.org/wiki/Rollover_(key) explains everything.

luni, 21 august 2017

ImportFromXlsx 4.0

duminică, 20 august 2017

Invalid keys in a TreeView Control

Each node of a TreeView has a key. The key is a string and must be unique [2].
Accidentally I discovered some unacceptable values for this key [3].

Generally, are rejected values that resembles a number:
- Integer literals, like '1'
- Integer literals followed by a period, like '1.'
- Integer literals preceded or folowed by a symbol sign, like '+1' or '1-'
- Numbers with commas between its digits, like '1,' ; '1,1,1' ; '1.,' or '.1,'
- Integer literals preceded or folowed by Space, Tabe or CR

Please try following example.

PUBLIC ofrm

ofrm=CREATEOBJECT("MyForm")

ofrm.show()

DEFINE CLASS MyForm as Form

autocenter = .T.

ADD OBJECT teeview as olecontrol WITH oleclass = 'COMCtl.treectrl', width = 300,height = 350

PROCEDURE init

LOCAL lcRoot,loRoot

lcRoot='Root'

loRoot = thisform.TeeView.Nodes.Add(, 1, m.lcRoot,'Root node')

loRoot.Expanded = .T.

* Rejected

thisform.AddNode(m.lcRoot,'1')

thisform.AddNode(m.lcRoot,'1.')

thisform.AddNode(m.lcRoot,'1,')

thisform.AddNode(m.lcRoot,'+1')

thisform.AddNode(m.lcRoot,'1.,')

thisform.AddNode(m.lcRoot,'.1,')

thisform.AddNode(m.lcRoot,'-1')

thisform.AddNode(m.lcRoot,'1+')

thisform.AddNode(m.lcRoot,'1-')

thisform.AddNode(m.lcRoot,' 1')

thisform.AddNode(m.lcRoot,'1 ')

thisform.AddNode(m.lcRoot,CHR(13) + '1')

thisform.AddNode(m.lcRoot,CHR(9) + '1')

thisform.AddNode(m.lcRoot,'1,1,1,1')

* Accepted

thisform.AddNode(m.lcRoot,CHR(13))

thisform.AddNode(m.lcRoot,CHR(9))

thisform.AddNode(m.lcRoot,'1 1')

thisform.AddNode(m.lcRoot,'1E')

thisform.AddNode(m.lcRoot,'1+1')

ENDPROC

PROCEDURE AddNode

LPARAMETERS lcRoot, lcKey

LOCAL loErr as Exception

TRY

thisform.TeeView.Nodes.Add(m.lcRoot, 4, m.lcKey,m.lcKey)

CATCH TO loErr

ACTIVATE SCREEN

? m.lcKey, loErr.ErrorNo , loErr.Message

ENDTRY

ENDPROC

ENDDEFINE

Bibliography
[1] TreeView Control
[2] Key Property
[3] The code the lead me to these conclusions

Related posts
http://praisachion.blogspot.com/2017/09/correlation-between-margin-and-fontsize.html
http://praisachion.blogspot.com/2017/08/invalid-keys-in-treeview-control.html

Vilhelm-Ion Praisach

Faceți căutări pe acest blog

marți, 22 august 2017

Easter eggs (4)

luni, 21 august 2017

ImportFromXlsx 4.0

duminică, 20 august 2017

Invalid keys in a TreeView Control

Translate

Faceți căutări pe acest blog

marți, 22 august 2017

Easter eggs (4)

luni, 21 august 2017

ImportFromXlsx 4.0

duminică, 20 august 2017

Invalid keys in a TreeView Control

Translate

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