ThemedWindow.HeaderItemContainerStyleSelector Property

Gets or sets an object that chooses a header item style based on custom logic. This is a dependency property.

Namespace: DevExpress.Xpf.Core

Assembly: DevExpress.Xpf.Core.v20.2.dll

NuGet Packages: DevExpress.WindowsDesktop.Wpf.Core, DevExpress.Wpf.Core

Declaration

C#

public StyleSelector HeaderItemContainerStyleSelector { get; set; }

VB.NET

Public Property HeaderItemContainerStyleSelector As StyleSelector

Property Value

Type	Description
StyleSelector	A StyleSelector descendant that chooses a style based on custom logic.

Remarks

The ThemedWindow.HeaderItemContainerStyle property defines the header items’ style. If you have more than one style that can be used to render property descriptions, you can implement custom logic to choose the required style. To do this, derive from the StyleSelector class, implement the SelectStyle method that returns the style which meets the required condition, and assign it to the HeaderItemContainerStyleSelector property.

If both the ThemedWindow.HeaderItemContainerStyle and HeaderItemContainerStyleSelector are specified, a property description is rendered using the style returned by the style selector. If the template selector returns null, a header item uses the style specified by the ThemedWindow.HeaderItemContainerStyle property.

The following code sample shows how to use the HeaderItemContainerStyleSelector:

XAML

<dx:ThemedWindow
 ...
      xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
      xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors">

  <dx:ThemedWindow.Resources>
      <Style x:Key="editorStyle" TargetType="{x:Type dxe:TextEdit}">
          <Setter Property="MinWidth" Value="50"/>
          <Setter Property="NullText" Value="Search"/>
      </Style>
      <Style x:Key="borderedHeaderItemStyle" TargetType="{x:Type dx:HeaderItemControl}">
          <Setter Property="ShowBorder" Value="False"/>
      </Style>
  </dx:ThemedWindow.Resources>

  <dx:ThemedWindow.HeaderItems>
      <dx:HeaderItemControl Content="DX HeaderItemControl" Tag="borderless"/>
      <dx:HeaderItemControl Content="DX HeaderItemControl" Tag="bordered"/>
      <dxe:TextEdit />
  </dx:ThemedWindow.HeaderItems>

  <dx:ThemedWindow.HeaderItemContainerStyleSelector>
      <local:SampleStyleSelector/>
  </dx:ThemedWindow.HeaderItemContainerStyleSelector>
</dx:ThemedWindow>

C#

 public class SampleStyleSelector : StyleSelector {
      public override Style SelectStyle(object item, DependencyObject container) {
          if(item is TextEdit) {                
              return (container as FrameworkElement).TryFindResource("editorStyle") as Style;
          }
          if(item is HeaderItemControl && (item as HeaderItemControl).Tag != null && (item as HeaderItemControl).Tag.ToString() == "bordered") {                
              return (container as FrameworkElement).TryFindResource("borderedHeaderItemStyle") as Style;
          }
          return base.SelectStyle(item, container);
      }
  }

VB.NET

Public Class SampleStyleSelector
  Inherits StyleSelector

  Public Overrides Function SelectStyle(ByVal item As Object, ByVal container As DependencyObject) As Style
      If TypeOf item Is TextEdit Then
          Return TryCast((TryCast(container, FrameworkElement)).TryFindResource("editorStyle"), Style)
      End If

      If TypeOf item Is HeaderItemControl AndAlso (TryCast(item, HeaderItemControl)).Tag IsNot Nothing AndAlso (TryCast(item, HeaderItemControl)).Tag.ToString() = "bordered" Then
          Return TryCast((TryCast(container, FrameworkElement)).TryFindResource("borderedHeaderItemStyle"), Style)
      End If

      Return MyBase.SelectStyle(item, container)
  End Function
End Class

The image below illustrates the result:

Refer to the Styles and Templates topic for more information.