Dropdown List

General

images/download/attachments/6045178/dropdown3.PNG

Component Palette Icon:

images/download/attachments/6045178/dropdown2.PNG

Description

The dropdown component is a great way to display a list of choices in a limited amount of space. The current selection is shown, and the choices are only presented when the user clicks on the dropdown button. The choices that are shown depend on the data property. This is a dataset, which can be typed in manually in the Designer, or (more commonly) it can be populated dynamically from a property binding, often a SQL Query binding.

It is often the case that you want to display choices to the user that are 'dressed up' versions of the actual choices. For instance, suppose that you are selecting choices for a downtime tracking entry. The choices might be: "Operator Error", "Machine Malfunction", and "Other". But, you really want to map these choices to some numeric code which is how the choice is stored. So, for instance, when the user chooses "Other" you really want to get the number 3. The dropdown component is perfect for such a use. The data property can be set up in one of three fashions, which control how the "selected values" properties change.

The 3 ways to set up the data dataset and the corresponding behavior is as follows:

Scenario 1: One column with a set of string values

Column1
Apples
Oranges
Bananas

Drop down displays values from the first column
Selected value is undefined
Selected String Value represents value from first column
Selected Label represents value from first column

Scenario 2: Two column with an integer and string column

Column1	Column2
201	Apples
202	Oranges
203	Bananas

Dropdown displays values from the second column
Selected Value represents a value from the first column
Selected String Value represents value from second column
Selected Label represents value from second column

Scenario 3: Two column with two string columns

Column1	Column2
APL	Apples
ORN	Oranges
BAN	Bananas

Dropdown displays values from second column
Selected Value is undefined
Selected String Value represents value from first column
Selected Label represents value from second column

The dropdown component can operate in one of three Selection Modes. These modes affect how the dropdown's current selection (defined by the values of its Selected Value, Selected String Value, and Selected Label properties) behave when the selection properties are set to values not present in the choice list, or conversely, when the choice list is set to a new dataset that doesn't contain the current selection:

• Strict. Selected values must always correlate to an option in the list defined by the Data property. If an invalid selection is set (via a binding or a script), the selection will be set to the values defined by the No Selection properties. If the Data property is set to a list that does not contain the current selection, the current selection will be reset to the No Selection values.

• Lenient. (default) Selected values are independent of the list defined by the Data property. This mode is useful to avoid race conditions that can cause problems in Strict mode when both the Data and the Selected Value properties are bound. If the current selection is not present in the Data list, the read-only property Selected Index will be -1.

• Editable. The same selection rules as defined by Lenient mode, except that the dropdown itself becomes editable, allowing a user to type in their own arbitrary value. This value will be set as the dropdown's Selected Label.

Properties

Name	Description	Property Type	Scripting	Category
Antialias	Draw with antialias on? Makes text smoother	boolean	.antialias	Appearance
Background Color	The background color of the component.	Color	.background	Appearance
Border	The border surrounding this component. NOTE that the border is unaffected by rotation.	Border	.border	Common
Cursor	The mouse cursor to use when hovering over this component.	int	.cursorCode	Common
Data	The data which fills up the combo box. Either a 1 or 2 column DataSet, with the first column being the value, and the second being the display	Dataset	.data	Data
Data Quality	The data quality code for any tag bindings on this component.	int	.dataQuality	Data
Dropdown Display Mode	Changes the dropdown's display	int	.mode	Appearance
Enabled	If disabled, a component cannot be used.	boolean	.componentEnabled	Common
Font	Font of text of this component	Font	.font	Appearance
Foreground Color	The foreground color of the component.	Color	.foreground	Appearance
Hide Table Columns?	A comma separated list of columns to hide from the dropdown table, eg. 0,2 (only used in table mode)	String	.hideTableColumns	Appearance
Horizontal Alignment	Determines the alignment of the contents along the X axis	int	.horizontalAlignment	Layout
Max Row Count	The number of rows to display in the dropdown list before displaying a scrollbar.	int	.maximumRowCount	Appearance
Max Table Height	The maximum height allowed for the dropdown table. (only used in table mode)	int	.maxTableHeight	Appearance
Max Table Width	The maximum width allowed for the dropdown table. (only used in table mode)	int	.maxTableWidth	Appearance
Mouseover Text	The text that is displayed in the tooltip which pops up on mouseover of this component.	String	.toolTipText	Common
Name	The name of this component.	String	.name	Common
No Selection Label	The label to display when nothing is selected.	String	.noSelectionLabel	Behavior
No Selection String	The string value when nothing is selected.	String	.noSelectionString	Behavior
No Selection Value	The value when nothing is selected.	int	.noSelectionValue	Behavior
Selected Index	The index of the selected item. (Read only. Usable in bindings and scripting.)	int	.selectedIndex	Uncategorized
Selected Label	The currently selected label	String	.selectedLabel	Data
Selected String Value	The currently selected value, if the value column is a string	String	.selectedStringValue	Data
Selected Value	The currently selected value	Integer	.selectedValue	Data
Selection Background	The background color of a selected cell in the dropdown list.	Color	.selectionBackground	Appearance
Selection Mode	The selection mode determines the behavior of the dropdown: whether its selected value must strictly be in the underlying set of choices, whether it is flexible, or even user-editable.	int	.selectionMode	Behavior
Show Table Header?	Selects whether or not the dropdown table header is displayed. (only used in table mode)	boolean	.showTableHeader	Appearance
Styles	Contains the component's styles	Dataset	.styles	Appearance
Vertical Alignment	Determines the alignment of the contents along the Y axis	int	.verticalAlignment	Layout
Visible	If disabled, the component will be hidden.	boolean	.visible	Common

Scripting

Scripting Functions

This component does not have scripting functions associated with it.

Extension Functions

This component does not have extension functions associated with it.

Event Handlers

focus

focusGained

This event occurs when a component that can receive input, such as a text box, receives the input focus. This usually occurs when a user clicks on the component or tabs over to it.

.source	The component that fired this event.
.oppositeComponent	The other component involved in this focus change. That is, the component that lost focus in order for this one to gain it, or vise versa.

focusLost

This event occurs when a component that had the input focus lost it to another component.

.source	The component that fired this event
.oppositeComponent	The other component involved in this focus change. That is, the component that lost focus in order for this one to gain it, or vise versa.

key

keyPressed

An integer that indicates whether the state was changed to "Selected" (on) or "Deselected" (off). Compare this to the event object's constants to determine what the new state is.

.source	The component that fired this event.
.keyCode	The key code for this event. Used with the `keyPressed` and `keyReleased` events. See below for the key code constants.
.keyChar	The character that was typed. Used with the `keyTyped` event.
.keyLocation	Returns the location of the key that originated this key event. Some keys occur more than once on a keyboard, e.g. the left and right shift keys. Additionally, some keys occur on the numeric keypad. This provides a way of distinguishing such keys. See the KEY_LOCATION constants, the keyTyped event always has a location of KEY_LOCATION_UNKNOWN.
.altDown	True (1) if the Alt key was held down during this event, false (0) otherwise.
.controlDown	True (1) if the Control key was held down during this event, false (0) otherwise.
.shiftDown	True (1) if the Shift key was held down during this event, false (0) otherwise.

keyReleased

Fires when a key is released and the source component has the input focus. Works for all characters, including non-printable ones, such as SHIFT and F3.

.source	The component that fired this event.
.keyCode	The key code for this event. Used with the `keyPressed` and `keyReleased` events. See below for the key code constants.
.keyChar	The character that was typed. Used with the `keyTyped` event.
.keyLocation	Returns the location of the key that originated this key event. Some keys occur more than once on a keyboard, e.g. the left and right shift keys. Additionally, some keys occur on the numeric keypad. This provides a way of distinguishing such keys. See the KEY_LOCATION constants in the documentation, the keyTyped event always has a location of KEY_LOCATION_UNKNOWN.
.altDown	True (1) if the Alt key was held down during this event, false (0) otherwise.
.controlDown	True (1) if the Control key was held down during this event, false (0) otherwise.
.shiftDown	True (1) if the Shift key was held down during this event, false (0) otherwise.

keyTyped

Fires when a key is pressed and then released when source component has the input focus. Only works for characters that can be printed on the screen.

.source	The component that fired this event.
.keyCode	The key code for this event. Used with the `keyPressed` and `keyReleased` events. See below for the key code constants.
.keyChar	The character that was typed. Used with the `keyTyped` event.
.keyLocation	Returns the location of the key that originated this key event. Some keys occur more than once on a keyboard, e.g. the left and right shift keys. Additionally, some keys occur on the numeric keypad. This provides a way of distinguishing such keys. See the KEY_LOCATION constants in the documentation, the keyTyped event always has a location of KEY_LOCATION_UNKNOWN.
.altDown	True (1) if the Alt key was held down during this event, false (0) otherwise.
.controlDown	True (1) if the Control key was held down during this event, false (0) otherwise.
.shiftDown	True (1) if the Shift key was held down during this event, false (0) otherwise.

mouse

mouseClicked

This event signifies a mouse click on the source component. A mouse click the combination of a mouse press and a mouse release, both of which must have occurred over the source component. Note that this event fires after the pressed and released events have fired.

.source	The component that fired this event.
.button	The code for the button that caused this event to fire.
.clickCount	The number of mouse clicks associated with this event.
.x	The x-coordinate (with respect to the source component) of this mouse event.
.y	The y-coordinate (with respect to the source component) of this mouse event.
.popupTrigger	Returns True (1) if this mouse event is a popup trigger. What constitutes a popup trigger is operating system dependent, which is why this abstraction exists.
.altDown	True (1) if the Alt key was held down during this event, false (0) otherwise.
.controlDown	True (1) if the Control key was held down during this event, false (0) otherwise.
.shiftDown	True (1) if the Shift key was held down during this event, false (0) otherwise.

mouseEntered

This event fires when the mouse enters the space over the source component.

.source	The component that fired this event.
.button	The code for the button that caused this event to fire.
.clickCount	The number of mouse clicks associated with this event.
.x	The x-coordinate (with respect to the source component) of this mouse event.
.y	The y-coordinate (with respect to the source component) of this mouse event.
.popupTrigger	Returns True (1) if this mouse event is a popup trigger. What constitutes a popup trigger is operating system dependent, which is why this abstraction exists.
.altDown	True (1) if the Alt key was held down during this event, false (0) otherwise.
.controlDown	True (1) if the Control key was held down during this event, false (0) otherwise.
.shiftDown	True (1) if the Shift key was held down during this event, false (0) otherwise.

mouseExited

This event fires when the mouse leaves the space over the source component.

.source	The component that fired this event.
.button	The code for the button that caused this event to fire.
.clickCount	The number of mouse clicks associated with this event.
.x	The x-coordinate (with respect to the source component) of this mouse event.
.y	The y-coordinate (with respect to the source component) of this mouse event.
.popupTrigger	Returns True (1) if this mouse event is a popup trigger. What constitutes a popup trigger is operating system dependent, which is why this abstraction exists.
.altDown	True (1) if the Alt key was held down during this event, false (0) otherwise.
.controlDown	True (1) if the Control key was held down during this event, false (0) otherwise.
.shiftDown	True (1) if the Shift key was held down during this event, false (0) otherwise.

mousePressed

This event fires when a mouse button is pressed down on the source component.

.source	The component that fired this event.
.button	The code for the button that caused this event to fire.
.clickCount	The number of mouse clicks associated with this event.
.x	The x-coordinate (with respect to the source component) of this mouse event.
.y	The y-coordinate (with respect to the source component) of this mouse event.
.popupTrigger	Returns True (1) if this mouse event is a popup trigger. What constitutes a popup trigger is operating system dependent, which is why this abstraction exists.
.altDown	True (1) if the Alt key was held down during this event, false (0) otherwise.
.controlDown	True (1) if the Control key was held down during this event, false (0) otherwise.
.shiftDown	True (1) if the Shift key was held down during this event, false (0) otherwise.

mouseReleased

This event fires when a mouse button is released, if that mouse button's press happened over this component.

.source	The component that fired this event.
.button	The code for the button that caused this event to fire.
.clickCount	The number of mouse clicks associated with this event.
.x	The x-coordinate (with respect to the source component) of this mouse event.
.y	The y-coordinate (with respect to the source component) of this mouse event.
.popupTrigger	Returns True (1) if this mouse event is a popup trigger. What constitutes a popup trigger is operating system dependent, which is why this abstraction exists.
.altDown	True (1) if the Alt key was held down during this event, false (0) otherwise.
.controlDown	True (1) if the Control key was held down during this event, false (0) otherwise.
.shiftDown	True (1) if the Shift key was held down during this event, false (0) otherwise.

mouseMotion

mouseDragged

Fires when the mouse moves over a component after a button has been pushed.

.source	The component that fired this event.
.button	The code for the button that caused this event to fire.
.clickCount	The number of mouse clicks associated with this event.
.x	The x-coordinate (with respect to the source component) of this mouse event.
.y	The y-coordinate (with respect to the source component) of this mouse event.
.popupTrigger	Returns True (1) if this mouse event is a popup trigger. What constitutes a popup trigger is operating system dependent, which is why this abstraction exists.
.altDown	True (1) if the Alt key was held down during this event, false (0) otherwise.
.controlDown	True (1) if the Control key was held down during this event, false (0) otherwise.
.shiftDown	True (1) if the Shift key was held down during this event, false (0) otherwise.

mouseMoved

Fires when the mouse moves over a component, but no buttons are pushed.

.source	The component that fired this event.
.button	The code for the button that caused this event to fire.
.clickCount	The number of mouse clicks associated with this event.
.x	The x-coordinate (with respect to the source component) of this mouse event.
.y	The y-coordinate (with respect to the source component) of this mouse event.
.popupTrigger	Returns True (1) if this mouse event is a popup trigger. What constitutes a popup trigger is operating system dependent, which is why this abstraction exists.
.altDown	True (1) if the Alt key was held down during this event, false (0) otherwise.
.controlDown	True (1) if the Control key was held down during this event, false (0) otherwise.
.shiftDown	True (1) if the Shift key was held down during this event, false (0) otherwise.

propertyChange

Fires whenever a bindable property of the source component changes. This works for standard and custom (dynamic) properties.

.source	The component that fired this event.
.newValue	The new value that this property changed to.
.oldValue	The value that this property was before it changed.
.propertyName	The name of the property that changed. NOTE: remember to always filter out these events for the property that you are looking for! Components often have many properties that change.

Customizers

Examples

Code Snippet

#The following code will return the first column value of the selection.
#This code would be on a button in the same container as the dropdown.
 
selRow = event.source.parent.getComponent('Dropdown').selectedIndex
pyData = system.dataset.toPyDataSet(event.source.parent.getComponent('Dropdown').data)
code = pyData[selRow][0]
print code

Display Multiple Columns in Dropdown

images/download/attachments/6045178/Dropdown1.png

Property Name	Value
Dropdown Display Mode	Table
Show Table Header	False