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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)

public virtual Style SelectStyle(
	Object item,
	DependencyObject container
)

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, null.

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 : 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.

<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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