public event DataLoadingEventHandler DataLoading

Public Event DataLoading As DataLoadingEventHandler

using DevExpress.DashboardCommon;
using DevExpress.DashboardWin;
using DevExpress.XtraEditors;
using System;
using System.Data;

namespace Dashboard_DataLoading_Example {
    public partial class Form1 : XtraForm {

        string dataFileName = string.Empty;

        public Form1() {
            InitializeComponent();
            dashboardViewer1.CustomizeDashboardTitle += DashboardViewer1_CustomizeDashboardTitle;
            dashboardViewer1.Dashboard = new Dashboard1();
            dashboardViewer1.DataLoading += DashboardViewer1_DataLoading;
        }

        private void DashboardViewer1_DataLoading(object sender, DataLoadingEventArgs e) {
            if (e.DataSourceName == "EnergyConsumptionBySector") {
                e.Data = GetData(dataFileName);
            }
        }

        public DataTable GetData(string fileName) {
            if (fileName == string.Empty) return null;
            DataSet xmlDataSet = new DataSet();
            xmlDataSet.ReadXml(fileName);
            return xmlDataSet.Tables["CountriesBySector"];
        }

        private void DashboardViewer1_CustomizeDashboardTitle(object sender, CustomizeDashboardTitleEventArgs e) {
            DashboardToolbarItem titleButton = new DashboardToolbarItem("Load Data",
                new Action<DashboardToolbarItemClickEventArgs>((args) =>
                {
                    LoadNewData();
                }));
            titleButton.Caption = "Load Data";
            e.Items.Add(titleButton);
        }
        private void LoadNewData() {
            dataFileName = @"..\..\Data\DashboardEnergyConsumptionBySector.xml";
            dashboardViewer1.ReloadData();
        }
    }
}

Imports DevExpress.DashboardCommon
Imports DevExpress.DashboardWin
Imports DevExpress.XtraEditors
Imports System
Imports System.Data

Namespace Dashboard_DataLoading_Example
    Partial Public Class Form1
        Inherits XtraForm

        Private dataFileName As String = String.Empty
        Public Sub New()
            InitializeComponent()
            AddHandler dashboardViewer1.CustomizeDashboardTitle, AddressOf DashboardViewer1_CustomizeDashboardTitle
            dashboardViewer1.Dashboard = New Dashboard1()
            AddHandler dashboardViewer1.DataLoading, AddressOf DashboardViewer1_DataLoading
        End Sub

        Private Sub DashboardViewer1_DataLoading(ByVal sender As Object, ByVal e As DataLoadingEventArgs)
            If e.DataSourceName = "EnergyConsumptionBySector" Then
                e.Data = GetData(dataFileName)
            End If
        End Sub

        Public Function GetData(ByVal fileName As String) As DataTable
            If fileName = String.Empty Then
                Return Nothing
            End If

            Dim xmlDataSet As New DataSet()
            xmlDataSet.ReadXml(fileName)
            Return xmlDataSet.Tables("CountriesBySector")
        End Function

        Private Sub DashboardViewer1_CustomizeDashboardTitle(ByVal sender As Object, ByVal e As CustomizeDashboardTitleEventArgs)
            Dim titleButton As DashboardToolbarItem = New DashboardToolbarItem("Load Data", New Action(Of DashboardToolbarItemClickEventArgs)(Sub(args)
                LoadNewData()
            End Sub))
            titleButton.Caption = "Load Data"
            e.Items.Add(titleButton)
        End Sub
        Private Sub LoadNewData()
            dataFileName = "..\..\Data\DashboardEnergyConsumptionBySector.xml"
            dashboardViewer1.ReloadData()
        End Sub
    End Class
End Namespace

dashboardDesigner1.DataSourceOptions.ObjectDataSourceLoadingBehavior = DevExpress.DataAccess.DocumentLoadingBehavior.LoadAsIs;
dashboardDesigner1.DataLoading += DashboardDesigner1_DataLoading;
dashboardDesigner1.AsyncDataLoading += DashboardDesigner1_AsyncDataLoading;

dashboardDesigner1.DataSourceOptions.ObjectDataSourceLoadingBehavior = DevExpress.DataAccess.DocumentLoadingBehavior.LoadAsIs
AddHandler dashboardDesigner1.DataLoading, AddressOf DashboardDesigner1_DataLoading
AddHandler dashboardDesigner1.AsyncDataLoading, AddressOf DashboardDesigner1_AsyncDataLoading