windowsforms-404561-controls-and-libraries-chart-control-end-user-features-tooltip-and-crosshair-cursor-customize-crosshair-cursor-at-runtime.md
The Chart Control’s Crosshair Cursor API contains the ChartControl.CustomDrawCrosshair event in whose handler the Crosshair Cursor’s elements can be customized individually:
Event parameters include:
e.CrosshairAxisLabelElementsGets the settings of crosshair axis label elements to customize their appearance.e.CrosshairElementGroupsProvides access to the settings of crosshair elements and crosshair group header elements to customize their appearance.e.CrosshairLegendElementsReturns crosshair legend elements to customize their appearance.e.CrosshairLineElementGets the settings of a crosshair line element to customize its appearance (color, line style).e.IndicatorLegendElementsReturns all indicator elements that the Crosshair Cursor shows in a legend.
This example shows how to use the ChartControl.CustomDrawCrosshair event to create a custom appearance for the crosshair cursor. This event is invoked when you select the Custom Draw Crosshair Cursor checkbox.
using System;
using System.Drawing;
using System.Windows.Forms;
using DevExpress.Drawing;
using DevExpress.XtraCharts;
namespace CustomDrawCrosshairCursor {
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
}
private void OnCheckEditCheckedChanged(object sender, EventArgs e) {
if (checkEdit1.Checked)
chartControl1.CustomDrawCrosshair += OnChartControlCustomDrawCrosshair;
else
chartControl1.CustomDrawCrosshair -= OnChartControlCustomDrawCrosshair;
}
private void OnChartControlCustomDrawCrosshair(object sender, CustomDrawCrosshairEventArgs e) {
// Specify the crosshair argument line color, dash style and thickness.
e.CrosshairLineElement.Color = Color.Green;
e.CrosshairLineElement.LineStyle.DashStyle = DashStyle.DashDot;
e.CrosshairLineElement.LineStyle.Thickness = 3;
// Specify the back color for the crosshair argument axis label.
foreach (CrosshairAxisLabelElement axisLabelElement in e.CrosshairAxisLabelElements)
axisLabelElement.BackColor = Color.Blue;
foreach (CrosshairElementGroup group in e.CrosshairElementGroups) {
CrosshairGroupHeaderElement groupHeaderElement = group.HeaderElement;
// Specify the text, text color and font for the crosshair group header element.
groupHeaderElement.Text = "Custom draw";
groupHeaderElement.TextColor = Color.Green;
groupHeaderElement.DXFont = new DXFont("SegoeUI", 12, DXFontStyle.Bold);
// Obtain the first series.
CrosshairElement element = group.CrosshairElements[0];
// Specify the color, dash style and thickness for the crosshair value lines.
element.LineElement.Color = Color.DarkViolet;
element.LineElement.LineStyle.DashStyle = DashStyle.Dash;
element.LineElement.LineStyle.Thickness = 2;
// Specify the text color and back color for the crosshair value labels.
element.AxisLabelElement.TextColor = Color.Red;
element.AxisLabelElement.BackColor = Color.Yellow;
// Format the text shown for the series in the crosshair cursor label. Specify the text color and marker size.
element.LabelElement.TextColor = Color.Red;
element.LabelElement.MarkerSize = new Size(15, 15);
element.LabelElement.Text = string.Format("{0}: A={1}; V={2}", element.Series.Name, element.SeriesPoint.Argument, element.SeriesPoint.Values[0]);
}
}
}
}
Imports System
Imports System.Drawing
Imports System.Windows.Forms
Imports DevExpress.Drawing
Imports DevExpress.XtraCharts
Namespace CustomDrawCrosshairCursor
Public Partial Class Form1
Inherits Form
Public Sub New()
InitializeComponent()
End Sub
Private Sub OnCheckEditCheckedChanged(ByVal sender As Object, ByVal e As EventArgs)
If checkEdit1.Checked Then
AddHandler chartControl1.CustomDrawCrosshair, AddressOf OnChartControlCustomDrawCrosshair
Else
RemoveHandler chartControl1.CustomDrawCrosshair, AddressOf OnChartControlCustomDrawCrosshair
End If
End Sub
Private Sub OnChartControlCustomDrawCrosshair(ByVal sender As Object, ByVal e As CustomDrawCrosshairEventArgs)
' Specify the crosshair argument line color, dash style and thickness.
e.CrosshairLineElement.Color = Color.Green
e.CrosshairLineElement.LineStyle.DashStyle = DashStyle.DashDot
e.CrosshairLineElement.LineStyle.Thickness = 3
' Specify the back color for the crosshair argument axis label.
For Each axisLabelElement As CrosshairAxisLabelElement In e.CrosshairAxisLabelElements
axisLabelElement.BackColor = Color.Blue
Next
For Each group As CrosshairElementGroup In e.CrosshairElementGroups
Dim groupHeaderElement As CrosshairGroupHeaderElement = group.HeaderElement
' Specify the text, text color and font for the crosshair group header element.
groupHeaderElement.Text = "Custom draw"
groupHeaderElement.TextColor = Color.Green
groupHeaderElement.DXFont = New DXFont("SegoeUI", 12, DXFontStyle.Bold)
' Obtain the first series.
Dim element As CrosshairElement = group.CrosshairElements(0)
' Specify the color, dash style and thickness for the crosshair value lines.
element.LineElement.Color = Color.DarkViolet
element.LineElement.LineStyle.DashStyle = DashStyle.Dash
element.LineElement.LineStyle.Thickness = 2
' Specify the text color and back color for the crosshair value labels.
element.AxisLabelElement.TextColor = Color.Red
element.AxisLabelElement.BackColor = Color.Yellow
' Format the text shown for the series in the crosshair cursor label. Specify the text color and marker size.
element.LabelElement.TextColor = Color.Red
element.LabelElement.MarkerSize = New Size(15, 15)
element.LabelElement.Text = String.Format("{0}: A={1}; V={2}", element.Series.Name, element.SeriesPoint.Argument, element.SeriesPoint.Values(0))
Next
End Sub
End Class
End Namespace
The example below displays the Crosshair Cursor for the current/previous point until the cursor reaches the next point in the series. Handle the ChartControl.CustomDrawCrosshair event to change the text of a displayed crosshair label.
private void Form1_Load(object sender, EventArgs e) {
// Create a chart.
ChartControl chart = new ChartControl();
chart.CustomDrawCrosshair += Chart_CustomDrawCrosshair;
}
private void Chart_CustomDrawCrosshair(object sender, CustomDrawCrosshairEventArgs e) {
var chart = (ChartControl)sender;
var diagram = (XYDiagram)chart.Diagram;
// Get diagram coordinates
var coords = diagram.PointToDiagram(chart.PointToClient(Cursor.Position));
// Get the current argument. Use the DateTimeArgument property if your scale is DateTime
var currentArgumentValue = coords.DateTimeArgument;
this.Text = currentArgumentValue.ToString();
var series = chart.Series[0];
// Find previous point in the series:
var previousPoint = series.Points
.OrderBy(p => ((SeriesPoint)p).DateTimeArgument)
.LastOrDefault(p => ((SeriesPoint)p).DateTimeArgument <= currentArgumentValue) as SeriesPoint;
if (previousPoint != null)
foreach (CrosshairElementGroup group in e.CrosshairElementGroups) {
CrosshairGroupHeaderElement groupHeaderElement = group.HeaderElement;
CrosshairElement element = group.CrosshairElements[0];
// Change the label's text. Use the DateTimeArgument property if your scale is DateTime
element.LabelElement.Text = string.Format("Argument: {0}, Value: {1}", previousPoint.DateTimeArgument, previousPoint.Values[0]);
}
}
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
' Create a chart.
Dim chart As New ChartControl()
AddHandler chart.CustomDrawCrosshair, AddressOf Chart_CustomDrawCrosshair
End Sub
Private Sub Chart_CustomDrawCrosshair(ByVal sender As Object, ByVal e As CustomDrawCrosshairEventArgs)
Dim chart = DirectCast(sender, ChartControl)
Dim diagram = CType(chart.Diagram, XYDiagram)
' Get diagram coordinates
Dim coords = diagram.PointToDiagram(chart.PointToClient(Cursor.Position))
' Get the current argument. Use the DateTimeArgument property if your scale is DateTime
Dim currentArgumentValue = coords.DateTimeArgument
Me.Text = currentArgumentValue.ToString()
Dim series = chart.Series(0)
' Find previous point in the series:
Dim previousPoint = TryCast(series.Points.OrderBy(Function(p) CType(p, SeriesPoint).DateTimeArgument).LastOrDefault(Function(p) CType(p, SeriesPoint).DateTimeArgument <= currentArgumentValue), SeriesPoint)
If previousPoint IsNot Nothing Then
For Each group As CrosshairElementGroup In e.CrosshairElementGroups
Dim groupHeaderElement As CrosshairGroupHeaderElement = group.HeaderElement
Dim element As CrosshairElement = group.CrosshairElements(0)
' Change the label's text. Use the DateTimeArgument property if your scale is DateTime
element.LabelElement.Text = String.Format("Argument: {0}, Value: {1}", previousPoint.DateTimeArgument, previousPoint.Values(0))
Next group
End If
End Sub
The example below shows how to hide a marker in the Crosshair Cursor Label.
private void stockChart_CustomDrawCrosshair(object sender, DevExpress.XtraCharts.CustomDrawCrosshairEventArgs e) {
foreach (CrosshairElementGroup g in e.CrosshairElementGroups) {
foreach (CrosshairElement el in g.CrosshairElements)
el.LabelElement.MarkerVisible = false;
}
}
Private Sub stockChart_CustomDrawCrosshair(ByVal sender As Object, ByVal e As DevExpress.XtraCharts.CustomDrawCrosshairEventArgs)
For Each g As CrosshairElementGroup In e.CrosshairElementGroups
For Each el As CrosshairElement In g.CrosshairElements
el.LabelElement.MarkerVisible = False
Next el
Next g
End Sub
This example demonstrates how to use the ChartControl.CustomDrawCrosshair event to modify the legend markers of bar series.
To access crosshair element groups, use the CustomDrawCrosshairEventArgs.CrosshairElementGroups property. Elements are separated into several groups when crosshair labels are displayed for each pane.
Use the following properties to access crosshair elements and customize them:
CrosshairElementGroup.HeaderElementGets the settings of crosshair group header elements to customize their appearance.CrosshairElementGroup.CrosshairElementsGets the settings of crosshair elements (crosshair value lines, crosshair value labels, crosshair labels) to customize their appearance.CrosshairElementBase.LabelElementReturns the Crosshair Cursor‘s label element to change its settings when using the ChartControl.CustomDrawCrosshair event to modify the Crosshair’s appearance.CrosshairElementBase.AxisLabelElementReturns the Crosshair Cursor‘s axis label element to change its settings when using the ChartControl.CustomDrawCrosshair event to modify the Crosshair’s appearance.CrosshairLabelElement.DXMarkerImageSpecifies the marker image of a crosshair cursor label when implementing custom draw in the crosshair cursor.
using CustomDrawCrosshairSample.Model;
using DevExpress.Drawing;
using DevExpress.XtraCharts;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;
namespace CustomDrawCrosshairSample {
public partial class Form1 : DevExpress.XtraEditors.XtraForm {
Dictionary<string, DXImage> photoCache = new Dictionary<string, DXImage>();
Dictionary<string, DXBitmap> bitmapCache = new Dictionary<string, DXBitmap>();
#region #Constants
const int borderSize = 2;
const int scaledPhotoWidth = 32;
const int scaledPhotoHeight = 34;
// Width and height of scaled photo with border.
const int totalWidth = 36;
const int totalHeight = 38;
// Rects required to create a custom legend series marker.
static readonly Rectangle photoRect = new Rectangle(
borderSize, borderSize,
scaledPhotoWidth, scaledPhotoHeight);
static readonly Rectangle totalRect = new Rectangle(
0, 0,
totalWidth, totalHeight);
#endregion
public Form1() {
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e) {
using (var context = new NwindDbContext()) {
InitPhotoCache(context.Employees);
chart.DataSource = context.Orders.ToList();
}
chart.SeriesDataMember = "Employee.FullName";
chart.SeriesTemplate.ArgumentDataMember = "OrderDate";
chart.SeriesTemplate.ValueDataMembers.AddRange("Freight");
XYDiagram diagram = chart.Diagram as XYDiagram;
if (diagram != null) {
diagram.AxisX.DateTimeScaleOptions.AggregateFunction = AggregateFunction.Sum;
diagram.AxisX.DateTimeScaleOptions.MeasureUnit = DateTimeMeasureUnit.Year;
}
chart.CustomDrawCrosshair += OnCustomDrawCrosshair;
}
void InitPhotoCache(IEnumerable<Employee> employees) {
photoCache.Clear();
foreach (var employee in employees) {
using (MemoryStream stream = new MemoryStream(employee.Photo)) {
if (!photoCache.ContainsKey(employee.FullName))
photoCache.Add(employee.FullName, DXImage.FromStream(stream));
}
}
}
#region #CustomDrawCrosshairHandler
private void OnCustomDrawCrosshair(object sender, CustomDrawCrosshairEventArgs e) {
foreach (CrosshairElementGroup group in e.CrosshairElementGroups) {
if (group.CrosshairElements[0] != null)
group.HeaderElement.Text = String.Format("Sales in {0:yyyy}", group.CrosshairElements[0].SeriesPoint.DateTimeArgument);
foreach (CrosshairElement element in group.CrosshairElements) {
DXBitmap image;
if (!bitmapCache.TryGetValue(element.Series.Name, out image)) {
image = new DXBitmap(totalWidth, totalHeight);
using (DXGraphics graphics = DXGraphics.FromImage(image)) {
using (DXSolidBrush brush = new DXSolidBrush(element.LabelElement.MarkerColor)) {
graphics.FillRectangle(brush, totalRect);
}
DXImage photo;
if (photoCache.TryGetValue(element.Series.Name, out photo))
graphics.DrawImage(photo, photoRect);
}
bitmapCache.Add(element.Series.Name, image);
}
element.LabelElement.DXMarkerImage = image;
element.LabelElement.MarkerSize = new Size(totalWidth, totalHeight);
}
}
}
#endregion
}
}
Imports CustomDrawCrosshairSample.Model
Imports DevExpress.Drawing
Imports DevExpress.XtraCharts
Imports System
Imports System.Collections.Generic
Imports System.Drawing
Imports System.IO
Imports System.Linq
Namespace CustomDrawCrosshairSample
Public Partial Class Form1
Inherits DevExpress.XtraEditors.XtraForm
Private photoCache As Dictionary(Of String, DXImage) = New Dictionary(Of String, DXImage)()
Private bitmapCache As Dictionary(Of String, DXBitmap) = New Dictionary(Of String, DXBitmap)()
#Region "#Constants"
Const borderSize As Integer = 2
Const scaledPhotoWidth As Integer = 32
Const scaledPhotoHeight As Integer = 34
' Width and height of scaled photo with border.
Const totalWidth As Integer = 36
Const totalHeight As Integer = 38
' Rects required to create a custom legend series marker.
Private Shared ReadOnly photoRect As Rectangle = New Rectangle(borderSize, borderSize, scaledPhotoWidth, scaledPhotoHeight)
Private Shared ReadOnly totalRect As Rectangle = New Rectangle(0, 0, totalWidth, totalHeight)
#End Region
Public Sub New()
InitializeComponent()
End Sub
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
Using context = New NwindDbContext()
InitPhotoCache(context.Employees)
chart.DataSource = context.Orders.ToList()
End Using
chart.SeriesDataMember = "Employee.FullName"
chart.SeriesTemplate.ArgumentDataMember = "OrderDate"
chart.SeriesTemplate.ValueDataMembers.AddRange("Freight")
Dim diagram As XYDiagram = TryCast(chart.Diagram, XYDiagram)
If diagram IsNot Nothing Then
diagram.AxisX.DateTimeScaleOptions.AggregateFunction = AggregateFunction.Sum
diagram.AxisX.DateTimeScaleOptions.MeasureUnit = DateTimeMeasureUnit.Year
End If
AddHandler chart.CustomDrawCrosshair, AddressOf OnCustomDrawCrosshair
End Sub
Private Sub InitPhotoCache(ByVal employees As IEnumerable(Of Employee))
photoCache.Clear()
For Each employee In employees
Using stream As MemoryStream = New MemoryStream(employee.Photo)
If Not photoCache.ContainsKey(employee.FullName) Then photoCache.Add(employee.FullName, DXImage.FromStream(stream))
End Using
Next
End Sub
#Region "#CustomDrawCrosshairHandler"
Private Sub OnCustomDrawCrosshair(ByVal sender As Object, ByVal e As CustomDrawCrosshairEventArgs)
For Each group As CrosshairElementGroup In e.CrosshairElementGroups
If group.CrosshairElements(0) IsNot Nothing Then group.HeaderElement.Text = String.Format("Sales in {0:yyyy}", group.CrosshairElements(0).SeriesPoint.DateTimeArgument)
For Each element As CrosshairElement In group.CrosshairElements
Dim image As DXBitmap
If Not bitmapCache.TryGetValue(element.Series.Name, image) Then
image = New DXBitmap(totalWidth, totalHeight)
Using graphics As DXGraphics = DXGraphics.FromImage(image)
Using brush As DXSolidBrush = New DXSolidBrush(element.LabelElement.MarkerColor)
graphics.FillRectangle(brush, totalRect)
End Using
Dim photo As DXImage
If photoCache.TryGetValue(element.Series.Name, photo) Then graphics.DrawImage(photo, photoRect)
End Using
bitmapCache.Add(element.Series.Name, image)
End If
element.LabelElement.DXMarkerImage = image
element.LabelElement.MarkerSize = New Size(totalWidth, totalHeight)
Next
Next
End Sub
#End Region
End Class
End Namespace
See Also