StyleSelector Class (System.Windows.Controls)

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.NET Framework Class Library
StyleSelector Class

Provides a way to apply styles based on custom logic.

Inheritance Hierarchy
System.Object
  System.Windows.Controls.StyleSelector

Namespace:  System.Windows.Controls
Assembly:  PresentationFramework (in PresentationFramework.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation
Syntax
Visual Basic
Public Class StyleSelector
C#
public class StyleSelector
Visual C++
public ref class StyleSelector
F#
type StyleSelector =  class end
XAML Object Element Usage
<StyleSelector .../>

The StyleSelector type exposes the following members.

Constructors
  Name Description
Public method StyleSelector Initializes a new instance of a StyleSelector.
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Methods
  Name Description
Public method Equals(Object) Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected method Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method GetHashCode Serves as a hash function for a particular type. (Inherited from Object.)
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method SelectStyle When overridden in a derived class, returns a Style based on custom logic.
Public method ToString Returns a string that represents the current object. (Inherited from Object.)
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Remarks

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

Examples

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.

Visual Basic

	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
C#

public class ListViewItemStyleSelector : StyleSelector
{
    public override Style SelectStyle(object item, 
        DependencyObject container)
    {
        Style st = new Style();
        st.TargetType = typeof(ListViewItem);
        Setter backGroundSetter = new Setter();
        backGroundSetter.Property = ListViewItem.BackgroundProperty;
        ListView listView = 
            ItemsControl.ItemsControlFromItemContainer(container) 
              as ListView;
        int index = 
            listView.ItemContainerGenerator.IndexFromContainer(container);
        if (index % 2 == 0)
        {
            backGroundSetter.Value = Brushes.LightBlue;
        }
        else
        {
            backGroundSetter.Value = Brushes.Beige;
        }
        st.Setters.Add(backGroundSetter);
        return st;
    }
}

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.

XAML

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

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

XAML

<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.

Version Information

.NET Framework

Supported in: 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
See Also

Reference

System.Windows.Controls Namespace
ItemsControl.ItemContainerStyleSelector
GroupStyle.ContainerStyleSelector
DataTemplateSelector

Other Resources

Styling and Templating