using System;
using System.Windows.Forms;
using DevExpress.Utils;
using DevExpress.XtraCharts;
// ...
        private void Form1_Load(object sender, EventArgs e) {
            chartControl1.CrosshairEnabled = DefaultBoolean.False;
            chartControl1.RuntimeHitTesting = true;
        }

        private void chartControl1_MouseMove(object sender, MouseEventArgs e) {
            // Obtain hit information under the test point.
            ChartHitInfo hi = chartControl1.CalcHitInfo(e.X, e.Y);

            // Obtain the series point under the test point.
            SeriesPoint point = hi.SeriesPoint;

            // Check whether the series point was clicked or not.
            if (point != null) {
                // Obtain the series point argument.
                string argument = "Argument: " + point.Argument.ToString();

                // Obtain series point values.
                string values = "Value(s): " + point.Values[0].ToString();
                if (point.Values.Length > 1) {
                    for (int i = 1; i < point.Values.Length; i++) {
                        values = values + ", " + point.Values[i].ToString();
                    }
                }

                // Show the tooltip.
                toolTipController1.ShowHint(argument + "\n" + values, "SeriesPoint Data");
            }
            else {
                // Hide the tooltip.
                toolTipController1.HideHint();
            }
        }

Imports System
Imports System.Windows.Forms
Imports DevExpress.Utils
Imports DevExpress.XtraCharts
' ...
        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
            chartControl1.CrosshairEnabled = DefaultBoolean.False
            chartControl1.RuntimeHitTesting = True
        End Sub

        Private Sub chartControl1_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs) Handles chartControl1.MouseMove
            ' Obtain hit information under the test point.
            Dim hi As ChartHitInfo = chartControl1.CalcHitInfo(e.X, e.Y)

            ' Obtain the series point under the test point.
            Dim point As SeriesPoint = hi.SeriesPoint

            ' Check whether the series point was clicked or not.
            If point IsNot Nothing Then
                ' Obtain the series point argument.
                Dim argument As String = "Argument: " & point.Argument.ToString()

                ' Obtain series point values.
                Dim values As String = "Value(s): " & point.Values(0).ToString()
                If point.Values.Length > 1 Then
                    For i As Integer = 1 To point.Values.Length - 1
                        values = values & ", " & point.Values(i).ToString()
                    Next i
                End If

                ' Show the tooltip.
                toolTipController1.ShowHint(argument & ControlChars.Lf & values, "SeriesPoint Data")
            Else
                ' Hide the tooltip.
                toolTipController1.HideHint()
            End If
        End Sub