windowsforms-118078-controls-and-libraries-diagrams-examples-how-to-use-the-customdrawitem-event-to-draw-custom-icons-inside-diagram-items.md
This example demonstrates how to use the DiagramControl.CustomDrawItem event to modify the standard drawing mechanism of diagram items (shapes, connectors, containers, etc.). In this example, a DiagramShape class descendant was created to introduce the Status property. Depending on the Status property value, a custom icon is drawn in the lower right-hand corner of a shape.
Note
The CustomDrawItemEventArgs.DefaultDraw method in the event args invokes certain parts of the standard shape drawing mechanism (the method parameter defines which ones). If you don’t call this method, shape content, border and background will not be drawn.
To apply custom drawing logic defined in the DiagramControl.CustomDrawItem event handler to your shapes, set the Handled property from the event args to true.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace XtraDiagram.CustomDraw {
static class Program {
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main() {
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
}
}
using DevExpress.Diagram.Core;
using DevExpress.Utils.Serializing;
using DevExpress.XtraDiagram;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace XtraDiagram.CustomDraw {
public partial class Form1 : DevExpress.XtraBars.Ribbon.RibbonForm {
public Form1() {
InitializeComponent();
RegisterShapes();
diagramControl1.CreateRibbon();
diagramControl1.CreateDocking();
}
public void RegisterShapes() {
DiagramControl.ItemTypeRegistrator.Register(typeof(DiagramShapeEx));
var stencil = new DiagramStencil("customShapes", "Custom Shapes");
stencil.RegisterTool(new FactoryItemTool("activeTaskShape", () => "Active Task", diagram => new DiagramShapeEx { Content = "Active Task", Status = Status.Active }, new System.Windows.Size(150, 100), false));
stencil.RegisterTool(new FactoryItemTool("inactiveTaskShape", () => "Inactive Task", diagram => new DiagramShapeEx { Content = "Inactive Task", Status = Status.Inactive }, new System.Windows.Size(150, 100), false));
DiagramToolboxRegistrator.RegisterStencil(stencil);
diagramControl1.OptionsBehavior.SelectedStencils = StencilCollection.Parse("customShapes");
}
private void diagramControl1_CustomGetEditableItemProperties(object sender, DiagramCustomGetEditableItemPropertiesEventArgs e) {
e.Properties.Add(TypeDescriptor.GetProperties(typeof(DiagramShapeEx))["Status"]);
}
private void diagramControl1_CustomDrawItem(object sender, CustomDrawItemEventArgs e) {
var shape = e.Item as DiagramShapeEx;
if (shape == null)
return;
e.DefaultDraw();
var imagePath = shape.Status == Status.Active ? "images/actions/apply_16x16.png" : "images/actions/cancel_16x16.png";
var image = DevExpress.Images.ImageResourceCache.Default.GetImage(imagePath);
var margin = 3f;
e.Graphics.DrawImage(image, new RectangleF(shape.Width - image.Width - margin, shape.Height - image.Height - margin, image.Width, image.Height));
e.Handled = true;
}
}
public class DiagramShapeEx : DiagramShape {
[XtraSerializableProperty, Category("Info")]
public Status Status { get; set; }
}
public enum Status { Active, Inactive }
}
Imports DevExpress.Diagram.Core
Imports DevExpress.Utils.Serializing
Imports DevExpress.XtraDiagram
Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Linq
Imports System.Text
Imports System.Threading.Tasks
Imports System.Windows.Forms
Namespace XtraDiagram.CustomDraw
Partial Public Class Form1
Inherits DevExpress.XtraBars.Ribbon.RibbonForm
Public Sub New()
InitializeComponent()
RegisterShapes()
diagramControl1.CreateRibbon()
diagramControl1.CreateDocking()
End Sub
Public Sub RegisterShapes()
DiagramControl.ItemTypeRegistrator.Register(GetType(DiagramShapeEx))
Dim stencil = New DiagramStencil("customShapes", "Custom Shapes")
stencil.RegisterTool(New FactoryItemTool("activeTaskShape", Function() "Active Task", Function(diagram) New DiagramShapeEx With {.Content = "Active Task", .Status = Status.Active}, New System.Windows.Size(150, 100), False))
stencil.RegisterTool(New FactoryItemTool("inactiveTaskShape", Function() "Inactive Task", Function(diagram) New DiagramShapeEx With {.Content = "Inactive Task", .Status = Status.Inactive}, New System.Windows.Size(150, 100), False))
DiagramToolboxRegistrator.RegisterStencil(stencil)
diagramControl1.OptionsBehavior.SelectedStencils = StencilCollection.Parse("customShapes")
End Sub
Private Sub diagramControl1_CustomGetEditableItemProperties(ByVal sender As Object, ByVal e As DiagramCustomGetEditableItemPropertiesEventArgs) Handles diagramControl1.CustomGetEditableItemProperties
e.Properties.Add(TypeDescriptor.GetProperties(GetType(DiagramShapeEx))("Status"))
End Sub
Private Sub diagramControl1_CustomDrawItem(ByVal sender As Object, ByVal e As CustomDrawItemEventArgs) Handles diagramControl1.CustomDrawItem
Dim shape = TryCast(e.Item, DiagramShapeEx)
If shape Is Nothing Then
Return
End If
e.DefaultDraw()
Dim imagePath = If(shape.Status = Status.Active, "images/actions/apply_16x16.png", "images/actions/cancel_16x16.png")
Dim image = DevExpress.Images.ImageResourceCache.Default.GetImage(imagePath)
Dim margin = 3F
e.Graphics.DrawImage(image, New RectangleF(shape.Width - image.Width - margin, shape.Height - image.Height - margin, image.Width, image.Height))
e.Handled = True
End Sub
End Class
Public Class DiagramShapeEx
Inherits DiagramShape
<XtraSerializableProperty, Category("Info")> _
Public Property Status() As Status
End Class
Public Enum Status
Active
Inactive
End Enum
End Namespace
Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Threading.Tasks
Imports System.Windows.Forms
Namespace XtraDiagram.CustomDraw
Friend NotInheritable Class Program
Private Sub New()
End Sub
''' <summary>
''' The main entry point for the application.
''' </summary>
<STAThread> _
Shared Sub Main()
Application.EnableVisualStyles()
Application.SetCompatibleTextRenderingDefault(False)
Application.Run(New Form1())
End Sub
End Class
End Namespace