Dec 222017
 
Multiple selection list boxes for Visual Basic.
File MLISTBOX.ZIP from The Programmer’s Corner in
Category BASIC Language
Multiple selection list boxes for Visual Basic.
File Name File Size Zip Size Zip Type
MLISTBOX.TXT 10329 3380 deflated
MLISTBOX.VBX 10144 4326 deflated
TPCREAD.ME 199 165 deflated

Download File MLISTBOX.ZIP Here

Contents of the MLISTBOX.TXT file


MLISTBOX.VBX

MLISTBOX.VBX is a custom control for Microsoft Visual Basic which provides
support for extended- and multiple-selection listboxes as well as the
standard single-selection listboxes that are built into Visual Basic.

This product is (pseudo) shareware. Information on distribution rights is
provided at the end of this file.

I welcome any comments, criticisms, suggestions, etc. I can be reached
via e-mail at:

[email protected]

Mike Warning
2/16/91


HOW TO USE CUSTOM CONTROLS

For those of you unfamiliar with using custom controls in Visual Basic, it is
really easy. First, copy the file ending with .VBX to your windows
directory. The start up Visual Basic and select 'Add File...' from the
'File' menu. Locate the custom control file (.VBX file) that you wish to
use and select it, then click 'OK'. The icon representing the custom control
should appear in the toolbox window and may be used just like any of the
standard controls. If you then save your project, the custom control will
be reloaded automatically the next time you open your project.


REFERENCE

Since I have made every effort to preserve the functionality of the original
single-selection listbox in my version, I will only address those properties
that are new or that I have expanded. For information on the standard
properties not covered here, refer to the Visual Basic documentation.

Note that when I refer to 'multiple-selection listboxes' below, I really
mean 'multiple- or extended-selection listboxes'.


Empty -
When reading this property, a TRUE will be returned if the listbox is
empty, otherwise a FALSE will be returned. Writing any value to this
property will force the listbox to reset, discarding any items that
it contains.

Example:
...
mlistbox1.Empty = TRUE ' Clear listbox
...


FindString -
This property is used to find strings in a listbox. When this property
is set, the 'FindIndex' property may then be checked to find the index
of the first string in the listbox matching the FindString. After
a string is found, this property will reset to the value of the string
in the listbox.

FindString will reset to null ("") if there is no string in the listbox
matching the value that you gave it.

Example:
...
mlistbox1.FindString = "J" ' Find an item beginning with "J"
If mlistbox1.FindString = "John" Then
...

See Also:
FindIndex


FindIndex -
This property hold the index of the string found using FindString. It
will be set to -1 if there is no matching string.

Example:
...
mlistbox1.FindString = "J" ' Find an item beginning with "J"
If mlistbox1.FindIndex = -1 then ' There isn't any
...

See Also:
FindString


hWnd -
This property is the window handle associated with the listbox and is
exactly like the 'hWnd' property that forms have. This function is
useful when a window handle must be passed to a Windows API function
or other DLL function.

Example:
...
word = GetWindowWord(mlistbox1.hWnd, GWW_ID)
...


ItemData -
This property associates a long-integer value with an item in the
listbox. For example, if you have a listbox containing names, you could
put there ages (or whatever) in the ItemData for a particular item.

This property is similar to the standard 'Tag' property, except that
it is numeric, and each item in the control can have it's own data.

Example:
...
mlistbox.ItemData(3) = 34
...


ListIndex -
For single-selection listboxes, ListIndex returns the index of the
currently selected item. For multiple-selection listboxes, ListIndex
returns the index of the last item that the user clicked on, the
'Selected' property may then be used to find out if that item is
currently selected or not.

If there is no current selection, single-selection listboxes will
return -1. If no selection has ever been made, multiple-selection
listboxes will return 0.

NOTE: The Windows SDK says that this should not work for multiple-
selection listboxes; however, it seems to work fine under Windows 3.0.
Therefore, I cannot guarantee that this property will work correctly
for multiple-selection listboxes under future versions of Windows.

Example:
...
If mlistbox1.ListIndex = -1 then
...


SelCount -
Returns the number of selected items in the listbox.

Example:
...
For i=1 to mlistbox1.SelCount - 1
...

See Also:
SelCount, Selected


Selected -
When read, this property returns a TRUE if the item is selected,
otherwise a FALSE is returned.

When writing, this property may be used to select (or deselect) an
item in the listbox. For single-selection listboxes, if another item
is currently selected, the selection will change to a new item. Also,
an item cannot be deselected in a single-selection listbox using this
property (use ListIndex instead).

Example:
...
for i=0 to mlistbox1.SelCount - 1
mlistbox1.Selected = TRUE ' select every item
next
...

See Also:
SelCount, SelList, ListIndex


SelList -
The property is an array that contains the indexes of the currently
selected items in the listbox. The first selected item is SelList(0),
etc.

Example:
...
For i=0 to mlistbox1.SelCount - 1
if mlistbox1.list(mlistbox1.SelList(i)) = "John" then
...

See Also:
SelCount, Selected


Style -
This property sets the style of the listbox (single-, extended-, or
multiple-selection).

Style = 0: single-selection. This type of listbox may only have one
item selected at a time.
Style = 1: extended-selection. This type of listbox may have more than
one item selected. The user must hold down the 'CTRL' or
'SHIFT' keys while clicking the mouse to select more than
one item
Style = 2: multiple-selection. This type of listbox may have more than
one item selected. The user does not need to hold down any
keys while selecting items.

You should probably set the Style property at design time. While you
may change the Style at run-time, doing so clears out the contents of
the listbox.

Example:
CONST EXTENDED_SELECTION = 1
...
mlistbox1.Style = EXTENDED_SELECTION
...


Text -
For single-selection listboxes, Text returns the currently selected item
in the listbox. For multiple-selection listboxes the item that was most
recently clicked is returned, you can then use the 'Selected', and
'ListIndex' properties to determine if the item is selected or not.

NOTE: The Windows SDK says that this should not work for multiple-
selection listboxes; however, it seems to work fine under Windows 3.0.
Therefore, I cannot guarantee that this property will work correctly
for multiple-selection listboxes under future versions of Windows.

Example:
...
if (mlistbox1.text = "John") then
...

See Also:
ListIndex, Selected


TopIndex -
Sets the index of the item that is at the top of the listbox. If you
try to set the top index to an item number less than 0, the listbox
will start from item 0. If you try to use an index that is to high
the listbox will not change.

Example:
...
mlistbox1.TopIndex = mlistbox1.TopIndex + 1 ' Scroll by one line
...


PROPERTIES

This is a comprehensive list of all properties supported by the control:

CtlName Index BackColor ForeColor Left
Top Width Height MousePointer
TabIndex TabStop DragIcon DragMode Enabled
Parent Tag Visible FontName FontBold
FontItalic FontStrikethru FontSize FontUnder
ListCount SelCount ListIndex TopIndex List
Empty SelList Style Text Sorted
Selected FindString FindIndex ItemData hWnd

EVENTS

Click DblClick DragDrop DragOver GotFocus
KeyDown KeyPress KeyUp LostFocus MouseDown
MouseMove MouseUp

METHODS

AddItem RemoveItem Refresh Load Unload


DISTRIBUTION RIGHTS

You are free to distribute this product separately from a product of your
own, as long as you distribute both this file, and the custom control file
(MLISTBOX.VBX).

If you wish to use this product in one of your own products, your rights
depend on what sort of product it is:

Public Domain: i.e. not for profit, you ask no monetary fee for someone
to use your product. In this case, you are free to distribute this control
as much as you wish.

Shareware: i.e. requesting that the user send you some money if they
like/use your product. In this case, please send me a postcard of your
home town or some feature thereabouts.

Commercial: i.e. for profit. In this case, please contact me (see below),
and we can arrange some mutually beneficial agreement.


I may be reached either through e-mail at:

[email protected]

or through regular mail at:

Mike Warning
6015 202nd St. S.W. #14
Lynnwood, WA 98036

If you wish a prompt reply, please use e-mail. I do not actually live at
the mailing address above, and it may take weeks/months to get anything to
me that is sent there.



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