DropListbox Control

The DROPLISTBOX control is made up of two parts: an EDITBOX and a drop-down ITEMBOX. A user can enter a value in the EDITBOX or select a suggested value from the drop-down items. The drop-down ITEMBOX is displayed by clicking on the arrow next to the EDITBOX .

Generally, a DROPLISTBOX is appropriate when there is a list of suggested choices, and an ITEMBOX is appropriate when you want to limit input to what is on the list. In addition, DROPLISTBOX controls save space on your dialog, because the full list is not displayed until the user clicks the down arrow.

You specify the items for the DROPLISTBOX list by placing a delimited list of values in the variable named in the control's Variable attribute.

You can give the EDITBOX portion of the control an initial value by placing a string, or a string with variable substitution ( "%variable%" ), in the Text attribute of the control's definition. The users choice is placed in the variable named in the Variable attribute when the dialog is dismissed.

Return Value:

The DROPLISTBOX control will return the users selection in the variable you supply as the Variable attribute in the controls definition.

Control Definition:

<dlg-variable>nn =`x, y, width, height, type, control-name, variable, pre-selected item, value, tab-order, style, font, textcolor, backgroundcolor`

For Example:

MyDialog003=`011,011,136,066,DROPLISTBOX,"DropListBox_1",dlVariable1,"Default Choice",DEFAULT,30,DEFAULT,DEFAULT,DEFAULT,DEFAULT`

Attribute

Value

Meaning

dlg-variable

MyDialog

The name of the dialog box.

003

The ordinal position of the control in the dialog box (starting with 1).

011

The horizontal coordinate of the upper left corner of the control in Dialog Units.

011

The vertical coordinate of the upper left corner of the control in Dialog Units.

width

136

The width of the control in Dialog Units

height

066

The height of the control in Dialog Units.

type

DROPLISTBOX

The type of control.

control-name

"DropListBox_1"

The name used to identify the control in a user defined callback procedure. The name cannot be more than 30 characters in length and MUST be unique. ( This attribute can only be used with 6.2 or later dialog formats. )

variable

dlVariable1

The name of the variable affected by the control. You specify the items for the DropListbox list by placing a delimited list of values in the variable named in the control's Variable attribute.

text

"Default Choice"

You can give the Editbox portion of the control an initial value by placing a string, or a string with variable substitution ( "%variable%" ), in the Text attribute of the control's definition. Use DEFAULT to display no initial value.

value

DEFAULT

Not applicable to this control.

tab-order

Allows you to specify a control's tab order independently of a control's position or name in the dialog template. Tab-order controls the order in which controls are accessed when the keyboard is used to navigate the dialog. It also influences which control is on top when controls have overlapping positions in the dialog. It can be any positive integer, but each control should have a unique number.

When you navigate through a dialog using the tab key, lower number controls will be given the keyboard focus before higher controls. Likewise, low-numbered overlapping controls will appear on top of higher numbered controls. If you specify the DEFAULT keyword for this attribute or if you give two controls the same tab order, a tab order will be arbitrarily assigned to the control.

Note: The dialog function, under certain circumstances, may change the tab order you specify. The GROUPBOX controls tab order may be adjusted so that it is smaller than any of the controls it contains. In addition, the tab order of the controls inside the GROUPBOX may be adjusted so that they are consecutive.

style

DEFAULT

Allows you to control the initial appearance and behavior of your control. Numbers represent each style and they can be combined, using the bit-wise OR (|) operator, to set multiple styles. The following table lists the style constants and their meanings.

Style	Meaning
@csInvisible (1)	Control is invisible
@csDisabled (2)	Control has disabled appearance and does not accept any user input, it would otherwise accept input.
@csListOnly (4)	Control will only accept values already in the drop down list portion of the control

Note: Specifying 0 for this attribute is equivalent to using the DEFAULT keyword and means that the control will exhibit default behavior.

font

DEFAULT

The font used to display a control's text. The font description should be delimited by double quote (") marks unless the attribute is set to DEFAULT. If this attribute is set to DEFAULT, the font specified as the value of the main dialog font will be used. If the main dialog font is set to DEFAULT, the system font is used. You do not need to provide any value for this attribute unless you are also specifying text or background color. For details see the Dialog Fonts topic. WARNING: If a font is selected that doesn't exist on the user's system, a substitution will be made. We recommend using commonly available fonts.

textcolor

DEFAULT

The color of text associated with a control. Color is specified by three vertical bar (|) delimited numbers ranging from 0 to 255. The numbers represent one of the RGB colors: red, green or blue, in that order. The complete color specification must be surrounded by double quotes (") unless the DEFAULT key word is used. If this attribute is set to DEFAULT, the color listed in the main dialog's textcolor will be used. If a color is not specified for the dialog, the system text color will be used.

Note: A single hexadecimal number can be used instead of a vertical delimited list to indicate color. The hexadecimal number must be preceded by the letter "h" or "H". For exemple, "hFFFFF" is equivalent to "255|255|255"

backgroundcolor

DEFAULT

Used to change the color displayed behind a controls text. Color is specified by three vertical bar (|) delimited numbers ranging from 0 to 255. The numbers represent one of the RGB colors (red, green or blue, in that order). The complete color specification must be surrounded by double quotes (") unless the DEFAULT keyword is used. If no color is specified or the DEFAULT keyword is used the system background color will be used.

Event Options

Use the DialogProcOptions function to control when your User-Defined-Callback procedure is called by its associated dialog. You can also use it to control your dialog's behavior, while your procedure is executing. You usually establish callback events during the first call to the procedure i.e., event 0, but this can be done during any call.

Event-Option-Code Values	Meaning
@deDlChange (8)	DROPLISTBOX/Combobox Item Change: User has changed the text appearing at the top of a DROPLISTBOX. This event can be triggered by the user picking a new item from the list portion of the control or by the user typing new text into the control.

Dialog Callback Procedure Function Options

DialogControlGet function returns text and state information associated with a control.

Request	Meaning
@dcContents (5)	Tab delimited list of all the items currently in the control, or a file wildcard mask if a FILELISTBOX is specified (i.e., "c:\temp\.").
@dcSelect (6)	Tab delimited list of the currently selected item(s) in the control. An empty string, if no item is selected.
@dcBackColor (11)	Background color specified by three vertical bar (\|) delimited numbers ranging from 0 to 255. If the control is using the system default color, the string "DEFAULT" is returned.
@dcTextColor (13)	Text color specified by three vertical bar (\|) delimited numbers ranging from 0 to 255. If the control is using the dialog's default text color, the string "DEFAULT" is returned.
@dcPosition (17)	Space delimited list of a control's position and size in dialog units relative to the dialog's client area. The first two numbers are the horizontal and vertical location of the upper-left corner of the control while the third and fourth numbers are the width and height of the control.
@dcMenuNames (18)	Tab delimited list of menu item names associated with the control, menu item or menu bar.
@dchWnd (19)	Window handle of a dialog control.

DialogControlSet function changes the text or appearance of a control.

Request	Meaning
@dcContents (5)	Tab delimited list of items to replace the existing list displayed by the control.
@dcSelect (6)	Tab delimited list one or more item you wish to be highlighted as selected. Use an empty string to cancel an existing selection. (Multiple item selection only applies to ITEMBOXs when multi-select is turned on. See IntControl (33, p1, 0, 0, 0) function documentation for information on multi-select )
@dcBackColor (11)	Background color. The color is specified by three vertical bar (\|) delimited numbers ranging from 0 to 255 or a single hexadecimal number preceded by the letter 'h'. To give the control the system default background color, use an empty string ""or the "DEFAULT "key string for this parameter.
@dcTextColor (13)	Text color. The color is specified by three vertical bar (\|) delimited numbers ranging from 0 to 255 or a single hexadecimal number preceded by the letter 'h'. To give the control the dialog's default text color, use an empty string ""or the "DEFAULT "key string for this parameter
@dcAddItem (14)	Text added as an item to the list displayed by the control. If the items in the control are sorted, the new item will be inserted in sort order.
@dcRemItem (15)	Text of item to be removed from the list displayed by the control. The text need not match the list item's case but must otherwise be an exact match.
@dcPosition (17)	Space delimited list of a control's position and size in dialog units relative to the dialog's client area. The first two numbers are the horizontal and vertical location of the upper-left corner of the control while the third and fourth numbers are the width and height of the control.

DialogControlState function changes a control’s style or gives control input focus.

Style	Meaning
@csInvisible (1)	Control is invisible
@csDisabled (2)	Control has disabled appearance and does not accept any user input, it would otherwise accept input.