public object Content { get; set; }

Public Property Content As Object

Imports System
Imports System.Collections.Generic
Imports System.Configuration
Imports System.Data
Imports System.Linq
Imports System.Windows

Namespace WpfApplication3
    ''' <summary>
    ''' Interaction logic for App.xaml
    ''' </summary>
    Partial Public Class App
        Inherits Application

        Private Sub OnAppStartup_UpdateThemeName(ByVal sender As Object, ByVal e As StartupEventArgs)

            DevExpress.Xpf.Core.ApplicationThemeHelper.UpdateApplicationThemeName()
        End Sub
    End Class
End Namespace

<Window x:Class="WpfApplication3.Window1" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core" 
        xmlns:dxb="http://schemas.devexpress.com/winfx/2008/xaml/bars"
        Title="Window1" Height="300" Width="300" >
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <dxb:BarContainerControl Grid.Row="0">
            <dxb:ToolBarControl Caption="Main Toolbar">
                <dxb:BarCheckItem Content="Bold" Glyph="{dx:DXImage Image=Bold_16x16.png}" CategoryName="Format" 
                                  CheckedChanged="checkBtnBold_CheckChanged"/>
                <dxb:BarCheckItem Content="Italic" Glyph="{dx:DXImage Image=Italic_16x16.png}" CategoryName="Format" 
                                  CheckedChanged="checkBtnItalic_CheckChanged"/>
            </dxb:ToolBarControl>
        </dxb:BarContainerControl>
    </Grid>
</Window>

<Application x:Class="WpfApplication3.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" StartupUri="Window1.xaml" Startup="OnAppStartup_UpdateThemeName">
    <Application.Resources>

    </Application.Resources>
</Application>

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Text
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Data
Imports System.Windows.Documents
Imports System.Windows.Input
Imports System.Windows.Media
Imports System.Windows.Media.Imaging
Imports System.Windows.Navigation
Imports System.Windows.Shapes
Imports DevExpress.Xpf.Bars

Namespace WpfApplication3
    ''' <summary>
    ''' Interaction logic for Window1.xaml
    ''' </summary>
    Partial Public Class Window1
        Inherits Window

        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub checkBtnItalic_CheckChanged(ByVal sender As Object, ByVal e As ItemClickEventArgs)
            '...
        End Sub

        Private Sub checkBtnBold_CheckChanged(ByVal sender As Object, ByVal e As DevExpress.Xpf.Bars.ItemClickEventArgs)
            '...
        End Sub
    End Class
End Namespace

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using DevExpress.Xpf.Bars;

namespace WpfApplication3 {
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window {
        public Window1() {
            InitializeComponent();
        }

        void checkBtnItalic_CheckChanged(object sender, ItemClickEventArgs e) {
            //...
        }

        void checkBtnBold_CheckChanged(object sender, DevExpress.Xpf.Bars.ItemClickEventArgs e) {
            //...
        }
    }
}

<dxb:ToolBarControl>
    <dxb:BarButtonItem Content="Refresh (F5)" Command="{Binding View.Commands.RefreshDataSource, ElementName=grid}"
                       Glyph="{dx:DXImage SvgImages/Icon Builder/Actions_Refresh.svg}" BarItemDisplayMode="ContentAndGlyph" />

<dxr:RibbonPageGroup Caption="File">
    <dxb:BarButtonItem x:Name="biNew" Content="New" LargeGlyph="{dx:DXImage Image=New_32x32.png}"/>
    <dxb:BarButtonItem x:Name="biOpen" Content="Open" Glyph="{dx:DXImage Image=Open_16x16.png}"/>

<ItemsControl>
    <dxb:BarSubItem AllowGlyphTheming="True" Content="My Title Item" dxb:CollectionAction.ContainerName="{x:Static dxdasht:DefaultBarItemNames.DashboardTitle_ExportToPopupMenu}">
        <dxb:BarButtonItem Content="Item1" />

<dxr:RibbonControl.PageHeaderItems>
    <dxb:BarEditItem x:Name="eRibbonStyle" Content="Ribbon Style:"
        EditWidth="100"

<dxb:ToolBarControl>
    <dxb:BarButtonItem Content="Refresh (F5)" Command="{Binding View.Commands.RefreshDataSource, ElementName=grid}" Glyph="{dx:DXImage SvgImages/Icon Builder/Actions_Refresh.svg}" BarItemDisplayMode="ContentAndGlyph" />
    <dxb:BarButtonItem Content="Edit (F2)" Command="{Binding View.Commands.EditFocusedRow, ElementName=grid}" Glyph="{dx:DXImage SvgImages/Icon Builder/Actions_Edit.svg}" BarItemDisplayMode="ContentAndGlyph" />

if (menuItem != null && menuItem.Name == DefaultBarItemNames.ContextMenu_Items_Cell_Actions_NewAllDayEvent) {
    menuItem.Content = "Create All-Day Appointment";
    break;

barSubItem.Name = "bsi" + propertyName;
barSubItem.Content = displayText;

BarButtonItem barButtonItem = new BarButtonItem();
barButtonItem.Content = "Save As...";
barButtonItem.Command = viewer.SaveAsCommand;

private void itemClick(object sender, DevExpress.Xpf.Bars.ItemClickEventArgs e) {
    MessageBox.Show("Item " + e.Item.Content + " has been clicked.");
}

InsertBarItemLinkAction.SetItemLinkIndex(actionAddAboutItem, 0);
actionAddAboutItem.Content = "About...";
actionAddAboutItem.ItemClick += new ItemClickEventHandler(btnAbout_ItemClick);

If menuItem IsNot Nothing AndAlso Equals(menuItem.Name, DefaultBarItemNames.ContextMenu_Items_Cell_Actions_NewAllDayEvent) Then
    menuItem.Content = "Create All-Day Appointment"
    Exit For

barSubItem.Name = "bsi" & propertyName
barSubItem.Content = displayText

Dim barButtonItem As New BarButtonItem()
barButtonItem.Content = "Save As..."
barButtonItem.Command = viewer.SaveAsCommand

Private Sub itemClick(ByVal sender As Object, ByVal e As DevExpress.Xpf.Bars.ItemClickEventArgs)
    MessageBox.Show("Item " & e.Item.Content & " has been clicked.")
End Sub

BarItemLinkActionBase.SetItemLinkIndex(actionAddAboutItem, 0)
actionAddAboutItem.Content = "About..."
AddHandler actionAddAboutItem.ItemClick, New ItemClickEventHandler(AddressOf btnAbout_ItemClick)