[XtraChartsLocalizableCategory(XtraChartsCategory.Appearance)]
public Color Color { get; set; }

<XtraChartsLocalizableCategory(XtraChartsCategory.Appearance)>
Public Property Color As Color

using DevExpress.Drawing;
using DevExpress.XtraCharts;
using DevExpress.XtraCharts.Heatmap;
using System;
using System.Drawing;
using System.Windows.Forms;

namespace HeatmapMatrixAdapterSample {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();

            HeatmapControl heatmap = new HeatmapControl();
            this.Controls.Add(heatmap);

            heatmap.Dock = DockStyle.Fill;

            HeatmapMatrixAdapter dataAdapter = new HeatmapMatrixAdapter();
            dataAdapter.XArguments = new string[] { "North", "South", "West", "East", "Central" };
            dataAdapter.YArguments = new string[] { "Components", "Clothing", "Bikes", "Accessories" };
            dataAdapter.Values = new double[,] {
                { 21.3, 50.1, 63.2, 64.4, 33.4 },
                { 32.3, 54.4, 81.3, 53.4, 54.9 },
                { 60.3, 49.1, 42.6, 48.4, 65.4 },
                { 45.3, 54.7, 70.3, 66.4, 56.6 }
            };
            heatmap.DataAdapter = dataAdapter;
            Palette palette = new Palette("Custom") { Color.White, Color.SkyBlue, Color.DarkBlue };
            RangeColorProvider colorProvider = new RangeColorProvider() { Palette = palette, ApproximateColors = true };
            colorProvider.RangeStops.Add(new Unit(0, UnitType.Percentage));
            colorProvider.RangeStops.Add(new Unit(20, UnitType.Absolute));
            colorProvider.RangeStops.Add(new Unit(40, UnitType.Absolute));
            colorProvider.RangeStops.Add(new Unit(60, UnitType.Absolute));
            colorProvider.RangeStops.Add(new Unit(90, UnitType.Absolute));
            colorProvider.RangeStops.Add(new Unit(1, UnitType.Percentage));
            dataAdapter.ColorProvider = colorProvider;

            HeatmapLabel label = heatmap.Label;
            label.Visible = true;
            label.Pattern = "{V:f0}";
            label.BackColor = Color.White;
            label.Color = Color.Black;
            label.DXFont = new DXFont("SegoeUI", 10);
            label.TextOrientation = HeatmapTextOrientation.Horizontal;
            label.Border.Visibility = DefaultBoolean.True;
            label.Border.Color = Color.DarkGray;
            label.Border.Thickness = 2;
        }
    }
}

Imports DevExpress.Drawing
Imports DevExpress.XtraCharts
Imports DevExpress.XtraCharts.Heatmap
Imports System
Imports System.Drawing
Imports System.Windows.Forms

Namespace HeatmapMatrixAdapterSample
    Public Partial Class Form1
        Inherits Form

        Public Sub New()
            InitializeComponent()
            Dim heatmap As HeatmapControl = New HeatmapControl()
            Me.Controls.Add(heatmap)
            heatmap.Dock = DockStyle.Fill
            Dim dataAdapter As HeatmapMatrixAdapter = New HeatmapMatrixAdapter()
            dataAdapter.XArguments = New String() {"North", "South", "West", "East", "Central"}
            dataAdapter.YArguments = New String() {"Components", "Clothing", "Bikes", "Accessories"}
            dataAdapter.Values = New Double(,) {
            {21.3, 50.1, 63.2, 64.4, 33.4},
            {32.3, 54.4, 81.3, 53.4, 54.9},
            {60.3, 49.1, 42.6, 48.4, 65.4},
            {45.3, 54.7, 70.3, 66.4, 56.6}}
            heatmap.DataAdapter = dataAdapter
            Dim palette As Palette = New Palette("Custom") From {
                System.Drawing.Color.White,
                System.Drawing.Color.SkyBlue,
                System.Drawing.Color.DarkBlue
            }
            Dim colorProvider As RangeColorProvider = New RangeColorProvider() With {
                .Palette = palette,
                .ApproximateColors = True
            }
            colorProvider.RangeStops.Add(New Unit(0, UnitType.Percentage))
            colorProvider.RangeStops.Add(New Unit(20, UnitType.Absolute))
            colorProvider.RangeStops.Add(New Unit(40, UnitType.Absolute))
            colorProvider.RangeStops.Add(New Unit(60, UnitType.Absolute))
            colorProvider.RangeStops.Add(New Unit(90, UnitType.Absolute))
            colorProvider.RangeStops.Add(New Unit(1, UnitType.Percentage))
            dataAdapter.ColorProvider = colorProvider
            Dim label As HeatmapLabel = heatmap.Label
            label.Visible = True
            label.Pattern = "{V:f0}"
            label.BackColor = Color.White
            label.Color = Color.Black
            label.DXFont = New DXFont("SegoeUI", 10)
            label.TextOrientation = HeatmapTextOrientation.Horizontal
            label.Border.Visibility = DefaultBoolean.True
            label.Border.Color = Color.DarkGray
            label.Border.Thickness = 2

        End Sub
    End Class
End Namespace

heatmap.Label.Pattern = "{V}";
heatmap.Label.Color = Color.Black;

Me.heatmap.Label.Pattern = "{V}"
Me.heatmap.Label.Color = System.Drawing.Color.Black
Me.heatmap.ToolTipEnabled = True