public Task<IList<AxisPointTuple>> GetAvailableFilterValuesAsync(
    string dashboardItemName
)

Public Function GetAvailableFilterValuesAsync(
    dashboardItemName As String
) As Task(Of IList(Of AxisPointTuple))

using DevExpress.DashboardCommon.ViewerData;
using DevExpress.XtraEditors;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace RandomFilterExample
{
    public partial class ViewerForm1 : XtraForm {
        public ViewerForm1() {
            InitializeComponent();
            dashboardViewer1.Initialized += OnDashboardViewerInitialized;

        }
        async void OnMouseClick(object sender, MouseEventArgs e) {
            await RandomFilter();
        }
        async Task RandomFilter() {
            string itemName = "choroplethMapDashboardItem1";
            IList<AxisPointTuple> filters = await dashboardViewer1.GetAvailableFilterValuesAsync(itemName);
            Random r = new Random();
            int index = r.Next(0, filters.Count - 1);
            await dashboardViewer1.SetMasterFilterAsync(itemName, filters[index]);
        }

        async void OnDashboardViewerInitialized(object sender, EventArgs e) {
            await RandomFilter();
        }
    }
}

Imports DevExpress.DashboardCommon.ViewerData
Imports DevExpress.XtraEditors
Imports System
Imports System.Collections.Generic
Imports System.Threading.Tasks
Imports System.Windows.Forms

Namespace RandomFilterExample
    Partial Public Class ViewerForm1
        Inherits XtraForm

        Public Sub New()
            InitializeComponent()
            AddHandler dashboardViewer1.Initialized, AddressOf OnDashboardViewerInitialized

        End Sub
        Private Async Overloads Sub OnMouseClick(ByVal sender As Object, ByVal e As MouseEventArgs) Handles simpleButton1.MouseClick
            Await RandomFilter()
        End Sub
        Private Async Function RandomFilter() As Task
            Dim itemName As String = "choroplethMapDashboardItem1"
            Dim filters As IList(Of AxisPointTuple) = Await dashboardViewer1.GetAvailableFilterValuesAsync(itemName)
            Dim r As New Random()
            Dim index As Integer = r.Next(0, filters.Count - 1)
            Await dashboardViewer1.SetMasterFilterAsync(itemName, filters(index))
        End Function

        Private Async Sub OnDashboardViewerInitialized(ByVal sender As Object, ByVal e As EventArgs)
            Await RandomFilter()
        End Sub
    End Class
End Namespace