XAML - ComboBox

A ComboBox represents a selection control that combines a non-editable textbox and a drop-down list box that allows users to select an item from a list. It either displays the current selection or is empty if there is no selected item. The hierarchical inheritance of ComboBox class is as follows −

Properties

Given below are the most commonly used properties of ComboBox.

Sr.No.	Property & Description
1	Background Gets or sets a brush that provides the background of the control. (Inherited from Control)
2	BorderThickness Gets or sets the border thickness of a control. (Inherited from Control)
3	FontFamily Gets or sets the font used to display text in the control. (Inherited from Control)
4	FontSize Gets or sets the size of the text in this control. (Inherited from Control)
5	FontStyle Gets or sets the style in which the text is rendered. (Inherited from Control)
6	FontWeight Gets or sets the thickness of the specified font. (Inherited from Control)
7	Foreground Gets or sets a brush that describes the foreground color. (Inherited from Control)
8	GroupStyle Gets a collection of GroupStyle objects that define the appearance of each level of groups. (Inherited from ItemsControl)
9	Header Gets or sets the content for the control's header.
10	Height Gets or sets the suggested height of a FrameworkElement. (Inherited from FrameworkElement)
11	HorizontalAlignment Gets or sets the horizontal alignment characteristics that are applied to a FrameworkElement when it is composed in a layout parent, such as a panel or items control. (Inherited from FrameworkElement)
12	IsDropDownOpen Gets or sets a value that indicates whether the drop-down portion of the ComboBox is currently open.
13	IsEditable Gets a value that indicates whether the user can edit text in the text box portion of the ComboBox. This property always returns false.
14	IsEnabled Gets or sets a value indicating whether the user can interact with the control. (Inherited from Control)
15	Margin Gets or sets the outer margin of a FrameworkElement. (Inherited from FrameworkElement)
16	Name Gets or sets the identifying name of the object. When a XAML processor creates the object tree from XAML markup, run-time code can refer to the XAMLdeclared object by this name. (Inherited from FrameworkElement)
17	Opacity Gets or sets the degree of the object's opacity. (Inherited from UIElement)
18	SelectedIndex Gets or sets the index of the selected item. (Inherited from Selector)
19	SelectedItem Gets or sets the selected item. (Inherited from Selector)
20	SelectedValue Gets or sets the value of the selected item, obtained by using the SelectedValuePath. (Inherited from Selector)
21	Style Gets or sets an instance Style that is applied for this object during layout and rendering. (Inherited from FrameworkElement
22	VerticalAlignment Gets or sets the vertical alignment characteristics that are applied to a FrameworkElement when it is composed in a parent object such as a panel or items control. (Inherited from FrameworkElement)
23	Width Gets or sets the width of a FrameworkElement. (Inherited from FrameworkElement)
24	ItemsSource Gets or sets an object source used to generate the content of the ItemsControl. (Inherited from ItemsControl)

Methods

Given below are the most commonly used methods of ComboBox.

Sr.No.	Method & Description
1	Arrange Positions child objects and determines a size for a UIElement. Parent objects that implement custom layout for their child elements should call this method from their layout override implementations to form a recursive layout update. (Inherited from UIElement)
2	FindName Retrieves an object that has the specified identifier name. (Inherited from FrameworkElement)
3	Focus Attempts to set the focus on the control. (Inherited from Control)
4	GetValue Returns the current effective value of a dependency property from a DependencyObject. (Inherited from DependencyObject)
5	IndexFromContainer Returns the index to the item that has the specified, generated container. (Inherited from ItemsControl)
6	OnDragEnter Called before the DragEnter event occurs. (Inherited from Control)
7	OnDragLeave Called before the DragLeave event occurs. (Inherited from Control)
8	OnDragOver Called before the DragOver event occurs. (Inherited from Control)
9	OnDrop Called before the Drop event occurs. (Inherited from Control)
10	OnKeyDown Called before the KeyDown event occurs. (Inherited from Control)
11	OnKeyUp Called before the KeyUp event occurs. (Inherited from Control)
12	OnLostFocus Called before the LostFocus event occurs. (Inherited from Control)
13	ReadLocalValue Returns the local value of a dependency property, if a local value is set. (Inherited from DependencyObject)
14	SetBinding Attaches a binding to a FrameworkElement, using the provided binding object. (Inherited from FrameworkElement)
15	SetValue Sets the local value of a dependency property on a DependencyObject. (Inherited from DependencyObject)

Events

Given below are the most commonly used events of ComboBox.

Sr.No.	Event & Description
1	DragEnter Occurs when the input system reports an underlying drag event with this element as the target. (Inherited from UIElement)
2	DragLeave Occurs when the input system reports an underlying drag event with this element as the origin. (Inherited from UIElement)
3	DragOver Occurs when the input system reports an underlying drag event with this element as the potential drop target. (Inherited from UIElement)
4	DragStarting Occurs when a drag operation is initiated. (Inherited from UIElement)
5	Drop Occurs when the input system reports an underlying drop event with this element as the drop target. (Inherited from UIElement)
6	DropCompleted Occurs when a drag-and-drop operation is ended. (Inherited from UIElement)
7	DropDownClosed Occurs when the drop-down portion of the ComboBox closes.
8	DropDownOpened Occurs when the drop-down portion of the ComboBox opens.
9	GotFocus Occurs when a UIElement receives focus. (Inherited from UIElement)
10	IsEnabledChanged Occurs when the IsEnabled property changes. (Inherited from Control)
11	KeyDown Occurs when a keyboard key is pressed while the UIElement has focus. (Inherited from UIElement)
12	KeyUp Occurs when a keyboard key is released while the UIElement has focus. (Inherited from UIElement)
13	LostFocus Occurs when a UIElement loses focus. (Inherited from UIElement)
14	SelectionChanged Occurs when the currently selected item changes. (Inherited from Selector)
15	SizeChanged Occurs when either the ActualHeight or the ActualWidth property changes value on a FrameworkElement. (Inherited from FrameworkElement)

Example

The following example contains two comboboxes. The first combobox is a simple one and the second one is editable.

Here is the XAML code in which two comboboxes have been created with some properties.

<Window x:Class = "XAMLComboBox.MainWindow" 
   xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
   xmlns:x = "http://schemas.microsoft.com/winfx/2006/xaml" 
   Title = "MainWindow" Height = "350" Width = "604"> 
	
   <Grid>
      <ComboBox Height = "20" Width = "100" HorizontalAlignment = "Left" Margin = "116,77,0,212"> 
         <ComboBoxItem Content = "Item #1"/> 
         <ComboBoxItem Content = "Item #2"/> 
         <ComboBoxItem Content = "Item #3"/> 
      </ComboBox> 
		
      <ComboBox IsEditable = "True" Height = "20" Width = "100" 
         HorizontalAlignment = "Right" Margin = "0,77,180,212"> 
         <ComboBoxItem Content = "Item #1"/> 
         <ComboBoxItem Content = "Item #2"/> 
         <ComboBoxItem Content = "Item #3"/> 
      </ComboBox>
   </Grid>
   
</Window>

When you compile and execute the above code, it will produce the following output −

We recommend you to execute the above example code and experiment with some other properties and events.

xaml_controls.htm