ComboBox  - AS3 Flex

The data property lets you pass a value to the component when you use it in an item renderer or item editor. You typically use data binding to bind a field of the data property to a property of this component.

The ComboBox control uses the listData property and the data property as follows. If the ComboBox is in a DataGrid control, it expects the dataField property of the column to map to a property in the data and sets selectedItem to that property. If the ComboBox control is in a List control, it expects the labelField of the list to map to a property in the data and sets selectedItem to that property. Otherwise, it sets selectedItem to the data itself.

You do not set this property in MXML.

此屬性可以做為資料繫結的來源。一旦修改此屬性，將傳送 dataChange 事件。

相關 API 元素

The set of items this component displays. This property is of type Object because the derived classes can handle a variety of data types such as Arrays, XML, ICollectionViews, and other classes. All are converted into an ICollectionView and that ICollectionView is returned if you get the value of this property; you will not get the value you set if it was not an ICollectionView.

Setting this property will adjust the selectedIndex property (and therefore the selectedItem property) if the selectedIndex property has not otherwise been set. If there is no prompt property, the selectedIndex property will be set to 0; otherwise it will remain at -1, the index used for the prompt string. If the selectedIndex property has been set and it is out of range of the new data provider, unexpected behavior is likely to occur.

此屬性可以做為資料繫結的來源。一旦修改此屬性，將傳送 collectionChange 事件。

A reference to the List control that acts as the drop-down in the ComboBox.

The IFactory that creates a ListBase-derived instance to use as the drop-down. The default value is an IFactory for List

此屬性可以做為資料繫結的來源。一旦修改此屬性，將傳送 dropdownFactoryChanged 事件。

The set of styles to pass from the ComboBox to the dropDown. Styles in the dropDownStyleName style will override these styles.

相關 API 元素

Width of the drop-down list, in pixels.

The default value is 100 or the width of the longest text in the dataProvider, whichever is greater.

此屬性可以做為資料繫結的來源。一旦修改此屬性，將傳送 dropdownWidthChanged 事件。

IFactory that generates the instances that displays the data for the drop-down list of the control. You can use this property to specify a custom item renderer for the drop-down list.

The control uses a List control internally to create the drop-down list. The default item renderer for the List control is the ListItemRenderer class, which draws the text associated with each item in the list, and an optional icon.

相關 API 元素

Name of the field in the items in the dataProvider Array to display as the label in the TextInput portion and drop-down list. By default, the control uses a property named label on each Array object and displays it.

However, if the dataProvider items do not contain a label property, you can set the labelField property to use a different property.

此屬性可以做為資料繫結的來源。一旦修改此屬性，將傳送 labelFieldChanged 事件。

User-supplied function to run on each item to determine its label. By default the control uses a property named label on each dataProvider item to determine its label. However, some data sets do not have a label property, or do not have another property that can be used for displaying as a label.

An example is a data set that has lastName and firstName fields but you want to display full names. You use labelFunction to specify a callback function that uses the appropriate fields and return a displayable String.

The labelFunction takes a single argument which is the item in the dataProvider and returns a String:

      myLabelFunction(item:Object):String
      

此屬性可以做為資料繫結的來源。一旦修改此屬性，將傳送 labelFunctionChanged 事件。

When a component is used as a drop-in item renderer or drop-in item editor, Flex initializes the listData property of the component with the appropriate data from the List control. The component can then use the listData property and the data property to display the appropriate information as a drop-in item renderer or drop-in item editor.

You do not set this property in MXML or ActionScript; Flex sets it when the component is used as a drop-in item renderer or drop-in item editor.

此屬性可以做為資料繫結的來源。一旦修改此屬性，將傳送 dataChange 事件。

相關 API 元素

The prompt for the ComboBox control. A prompt is a String that is displayed in the TextInput portion of the ComboBox when selectedIndex = -1. It is usually a String like "Select one...". If there is no prompt, the ComboBox control sets selectedIndex to 0 and displays the first item in the dataProvider.

Maximum number of rows visible in the ComboBox control list. If there are fewer items in the dataProvider, the ComboBox shows only as many items as there are in the dataProvider.

預設值為 5。

此屬性可以做為資料繫結的來源。一旦修改此屬性，將傳送 resize 事件。