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StyleSelector.SelectStyle Method

When overridden in a derived class, returns a Style based on custom logic.

Namespace:  System.Windows.Controls
Assembly:  PresentationFramework (in PresentationFramework.dll)

'Declaration
Public Overridable Function SelectStyle ( _
	item As Object, _
	container As DependencyObject _
) As Style

Parameters

item
Type: System.Object

The content.

container
Type: System.Windows.DependencyObject

The element to which the style will be applied.

Return Value

Type: System.Windows.Style
Returns an application-specific style to apply; otherwise, Nothing.

To create a StyleSelector that applies a style based on custom logic, create a subclass of the StyleSelector class and implement the SelectStyle method.

The following example shows how to define a StyleSelector that defines a Style for a row. This example defines the Background color according to the row index.

	Public Class ListViewItemStyleSelector
		Inherits StyleSelector
		Public Overrides Function SelectStyle(ByVal item As Object, ByVal container As DependencyObject) As Style
			Dim st As New Style()
			st.TargetType = GetType(ListViewItem)
			Dim backGroundSetter As New Setter()
			backGroundSetter.Property = ListViewItem.BackgroundProperty
			Dim listView As ListView = TryCast(ItemsControl.ItemsControlFromItemContainer(container), ListView)
			Dim index As Integer = listView.ItemContainerGenerator.IndexFromContainer(container)
			If index Mod 2 = 0 Then
				backGroundSetter.Value = Brushes.LightBlue
			Else
				backGroundSetter.Value = Brushes.Beige
			End If
			st.Setters.Add(backGroundSetter)
			Return st
		End Function
	End Class

The following example shows how to define a ResourceKey for the StyleSelector. The namespc prefix maps to a CLR namespace and the corresponding assembly where the StyleSelector is defined. For more information, see XAML Namespaces and Namespace Mapping for WPF XAML.

<namespc:ListViewItemStyleSelector x:Key="myStyleSelector"/>

The following example shows how to set the ItemContainerStyleSelector property of a ListView to this StyleSelector resource.

<ListView 
      ItemsSource="{Binding Source={StaticResource EmployeeData}, 
                                        XPath=Employee}"
      ItemContainerStyleSelector="{DynamicResource myStyleSelector}" >      
  <ListView.View>
    <GridView>
      <GridViewColumn DisplayMemberBinding="{Binding XPath=FirstName}" 
                      Header="First Name" Width="120"/>
      <GridViewColumn DisplayMemberBinding="{Binding XPath=LastName}" 
                      Header="Last Name" Width="120"/>
      <GridViewColumn DisplayMemberBinding="{Binding XPath=FavoriteCity}" 
                      Header="Favorite City" Width="120"/>
    </GridView>
  </ListView.View>
</ListView>

For an example of how to create a selector to choose a defined style resource, see the implementation of DataTemplateSelector.SelectTemplate, which allows you to use custom logic to select a DataTemplate, based on a similar concept.

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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