HeatmapControl.CustomizeHeatmapToolTip Event

const int ThresholdValue = 50;

public Form1() {
    InitializeComponent();
    // ...
    heatmap.ToolTipEnabled = true;
    heatmap.ToolTipController = new DevExpress.Utils.ToolTipController { AllowHtmlText = true };
    heatmap.CustomizeHeatmapToolTip += OnHeatmapCustomizeHeatmapToolTip;
}

private void OnHeatmapCustomizeHeatmapToolTip(object sender, CustomizeHeatmapToolTipEventArgs e) {
    double cellValue = (double)e.HeatmapCell.ColorValue;
    if (cellValue > ThresholdValue) {
        e.Title = "Sale Info";
        e.Text = $"Total: <color=green>${cellValue}K</color>";
    }
}

Const ThresholdValue As Integer = 50

Public Sub New()
    heatmap.ToolTipEnabled = True
    heatmap.ToolTipController = New DevExpress.Utils.ToolTipController With {
        .AllowHtmlText = True
    }
    heatmap.CustomizeHeatmapToolTip += AddressOf OnHeatmapCustomizeHeatmapToolTip
End Sub

Private Sub OnHeatmapCustomizeHeatmapToolTip(ByVal sender As Object, ByVal e As CustomizeHeatmapToolTipEventArgs)
    Dim cellValue As Double = CDbl(e.HeatmapCell.ColorValue)

    If cellValue > ThresholdValue Then
        e.Title = "Sale Info"
        e.Text = $"Total: <color=green>${cellValue}K</color>"
    End If
End Sub