<Dashboard>
...
    <CustomProperties>
        <DashboardDescription>This dashboard shows statistics on sales of bicycles, related equipment and accessories. ...</DashboardDescription>
    </CustomProperties>
</Dashboard>

var currentDescription = viewer.Dashboard.CustomProperties.GetValue("DashboardDescription");

Dim currentDescription = viewer.Dashboard.CustomProperties.GetValue("DashboardDescription")

using DevExpress.DashboardCommon;
using System;
using System.Collections.Generic;
using System.Linq;

namespace WindowsFormsAppCustomProperties {
    public static class CustomPropertyExtensions {

        public static T GetValue<T>(this CustomProperties property, string name) where T : struct {
            var value = property.GetValue(name);
            if(value == null) return default(T);
            return (T)Convert.ChangeType(value, typeof(T));
        }

        public static EnumType ConvertToEnum<EnumType>(this String enumValue) {
            return (EnumType)Enum.Parse(typeof(EnumType), enumValue);
        }
        public static string ConvertToString(this Enum enumValue) {
            return Enum.GetName(enumValue.GetType(), enumValue);
        }
    }
}

Imports DevExpress.DashboardCommon
Imports System
Imports System.Collections.Generic
Imports System.Linq

Namespace WindowsFormsAppCustomProperties
    Public NotInheritable Class CustomPropertyExtensions

        Private Sub New()
        End Sub
         _
        Public Shared Function GetValue(Of T As Structure)(ByVal [property] As CustomProperties, ByVal name As String) As T
            Dim value = [property].GetValue(name)
            If value Is Nothing Then
                Return Nothing
            End If
            Return CType(Convert.ChangeType(value, GetType(T)), T)
        End Function

         _
        Public Shared Function ConvertToEnum(Of EnumType)(ByVal enumValue As String) As EnumType
            Return CType(System.Enum.Parse(GetType(EnumType), enumValue), EnumType)
        End Function
         _
        Public Shared Function ConvertToString(ByVal enumValue As System.Enum) As String
            Return System.Enum.GetName(enumValue.GetType(), enumValue)
        End Function
    End Class
End Namespace

var newValue = designer.Dashboard.Items[itemName].CustomProperties.GetValue<CheckMode>(PropertyName);

Dim newValue = designer.Dashboard.Items(itemName).CustomProperties.GetValue(Of CheckMode)(PropertyName)

public Form1() {
    InitializeComponent();
    new WinDashboardDescriptionViewer(dashboardViewer1);
    dashboardViewer1.LoadDashboard("../../Dashboard/newDashboard.xml");
}

Public Sub New()
    InitializeComponent()
    Dim TempWinDashboardDescriptionViewer As WinDashboardDescriptionViewer = New WinDashboardDescriptionViewer(dashboardViewer1)
    dashboardViewer1.LoadDashboard("../../Dashboard/newDashboard.xml")
End Sub

using DevExpress.DashboardWin;
using DevExpress.Utils.Svg;
using DevExpress.XtraCharts;
using System;

namespace WindowsFormsAppCustomProperties {
    public class ViewerScaleBreak {
        public static readonly string PropertyName = "ScaleBreak";
        readonly IDashboardControl dashboardControl;
        readonly SvgImage titleDescriptionImage;
        public ViewerScaleBreak(DashboardViewer dashboardControl, SvgImage barImage = null) {
            this.dashboardControl = dashboardControl;
            dashboardControl.DashboardItemControlUpdated += DashboardControl_DashboardItemControlUpdated;
        }
        void DashboardControl_DashboardItemControlUpdated(object sender, DashboardItemControlEventArgs e) {
            if(e.ChartControl != null) {
                bool value = Convert.ToBoolean(dashboardControl.Dashboard.Items[e.DashboardItemName].CustomProperties.GetValue(PropertyName));
                UpdateChart(e.ChartControl, value);
            }
        }
        void UpdateChart(ChartControl chart, bool scaleBreakEnabled) {
            if(chart.Diagram != null)
                ((XYDiagram)chart.Diagram).SecondaryAxesY[0].AutoScaleBreaks.Enabled = scaleBreakEnabled;
        }
    }
}

Imports DevExpress.DashboardWin
Imports DevExpress.Utils.Svg
Imports DevExpress.XtraCharts
Imports System

Namespace WindowsFormsAppCustomProperties
    Public Class ViewerScaleBreak
        Public Shared ReadOnly PropertyName As String = "ScaleBreak"
        Private ReadOnly dashboardControl As IDashboardControl
        Private ReadOnly titleDescriptionImage As SvgImage
        Public Sub New(ByVal dashboardControl As DashboardViewer, Optional ByVal barImage As SvgImage = Nothing)
            Me.dashboardControl = dashboardControl
            AddHandler dashboardControl.DashboardItemControlUpdated, AddressOf DashboardControl_DashboardItemControlUpdated
        End Sub
        Private Sub DashboardControl_DashboardItemControlUpdated(ByVal sender As Object, ByVal e As DashboardItemControlEventArgs)
            If e.ChartControl IsNot Nothing Then
                Dim value As Boolean = Convert.ToBoolean(dashboardControl.Dashboard.Items(e.DashboardItemName).CustomProperties.GetValue(PropertyName))
                UpdateChart(e.ChartControl, value)
            End If
        End Sub
        Private Sub UpdateChart(ByVal chart As ChartControl, ByVal scaleBreakEnabled As Boolean)
            If chart.Diagram IsNot Nothing Then
                CType(chart.Diagram, XYDiagram).SecondaryAxesY(0).AutoScaleBreaks.Enabled = scaleBreakEnabled
            End If
        End Sub
    End Class
End Namespace

using DevExpress.DashboardWin;
using DevExpress.Utils.Svg;
using System;
using System.Windows.Forms;

namespace WindowsFormsAppCustomProperties {
    public class DescriptionViewer {
        public static readonly string PropertyName = "DashboardDescription";
        readonly IDashboardControl dashboardControl;
        readonly SvgImage titleDescriptionImage;

        public DescriptionViewer(IDashboardControl dashboardControl, SvgImage titleDescriptionImage = null) {
            this.dashboardControl = dashboardControl;
            this.titleDescriptionImage = titleDescriptionImage;
            dashboardControl.CustomizeDashboardTitle += DashboardControl_CustomizeDashboardTitle;
        }
        void DashboardControl_CustomizeDashboardTitle(object sender, CustomizeDashboardTitleEventArgs e) {
            string text = dashboardControl.Dashboard.CustomProperties.GetValue(PropertyName);
            if (!string.IsNullOrEmpty(text)) {
                DashboardToolbarItem showDataItem = new DashboardToolbarItem("Description",
                    new Action<DashboardToolbarItemClickEventArgs>((args) => {
                        MessageBox.Show(text, "Description");
                    }));
                showDataItem.SvgImage = titleDescriptionImage;
                e.Items.Insert(0, showDataItem);
            }
        }
    }
}

Imports DevExpress.DashboardWin
Imports DevExpress.Utils.Svg
Imports System
Imports System.Windows.Forms

Namespace WindowsFormsAppCustomProperties
    Public Class DescriptionViewer
        Public Shared ReadOnly PropertyName As String = "DashboardDescription"
        Private ReadOnly dashboardControl As IDashboardControl
        Private ReadOnly titleDescriptionImage As SvgImage

        Public Sub New(ByVal dashboardControl As IDashboardControl, Optional ByVal titleDescriptionImage As SvgImage = Nothing)
            Me.dashboardControl = dashboardControl
            Me.titleDescriptionImage = titleDescriptionImage
            AddHandler dashboardControl.CustomizeDashboardTitle, AddressOf DashboardControl_CustomizeDashboardTitle
        End Sub
        Private Sub DashboardControl_CustomizeDashboardTitle(ByVal sender As Object, ByVal e As CustomizeDashboardTitleEventArgs)
            Dim text As String = dashboardControl.Dashboard.CustomProperties.GetValue(PropertyName)
            If (Not String.IsNullOrEmpty(text)) Then
                Dim showDataItem As New DashboardToolbarItem("Description", New Action(Of DashboardToolbarItemClickEventArgs)(Function(args) AnonymousMethod1(args, text)))
                showDataItem.SvgImage = titleDescriptionImage
                e.Items.Insert(0, showDataItem)
            End If
        End Sub

        Private Function AnonymousMethod1(ByVal args As Object, ByVal text As String) As Boolean
            MessageBox.Show(text, "Description")
            Return True
        End Function
    End Class
End Namespace