NavBarControl.CustomDrawGroupClientBackground Event

Provides the ability to perform custom painting of group client areas.

Namespace: DevExpress.XtraNavBar

Assembly: DevExpress.XtraNavBar.v18.1.dll

Declaration

C#

public event CustomDrawObjectEventHandler CustomDrawGroupClientBackground

VB.NET

Public Event CustomDrawGroupClientBackground As CustomDrawObjectEventHandler

Event Data

The CustomDrawGroupClientBackground event's data class is CustomDrawObjectEventArgs. The following properties provide information specific to this event:

Property	Description
Appearance	Gets the painted element’s appearance settings.
Cache	Gets an object which specifies the storage for the most used pens, fonts and brushes.
Graphics	Gets an object used to paint the object.
Handled	Gets or sets a value specifying whether the control must perform default painting after an event handler has been executed.
ObjectInfo	Gets an object providing information on the element being painted.
RealBounds	Gets the bounding rectangle of the painted object.

Remarks

Write a CustomDrawGroupClientBackground event handler to perform custom painting of group client areas. Set the CustomDrawObjectEventArgs.Handled property of the event parameter to true to disable default painting. Other properties of the event parameter allow you to identify the group whose client area is painted and provide all necessary information to paint it.

Note

The control’s events designed to change the appearance or rendering of control elements must not be used to update cell values or to modify the control’s layout. Any inappropriate operation which causes a layout update, may break the normal control behavior.

Example

The following sample code handles the NavBarControl.CustomDrawGroupClientBackground event to fill the top and bottom portions of a group’s client background with linear gradient brushes of opposing color.

The image below shows the result.

C#

using System.Drawing.Drawing2D;
using DevExpress.XtraNavBar.ViewInfo;

private void navBarControl1_CustomDrawGroupClientBackground(object sender, 
  CustomDrawObjectEventArgs e) {
   // calculating the top and bottom part rectangles
   Rectangle rect = e.RealBounds;
   int halfHeight = rect.Height / 2;
   Rectangle topRect = new Rectangle(rect.Left, rect.Top, rect.Width, halfHeight);
   Rectangle bottomRect = new Rectangle(rect.Left, rect.Top + halfHeight, 
     rect.Width, halfHeight);

   // creating brushes for the top and bottom parts
   Color outerColor = Color.White;
   Color innerColor = Color.LightSkyBlue;
   LinearGradientBrush topBrush = new LinearGradientBrush(topRect, outerColor, innerColor,
     LinearGradientMode.Vertical);
   LinearGradientBrush bottomBrush = new LinearGradientBrush(bottomRect, innerColor, 
     outerColor, LinearGradientMode.Vertical);

   // filling the top and bottom rectangles with the created brushes
   e.Graphics.FillRectangle(topBrush, topRect);
   e.Graphics.FillRectangle(bottomBrush, bottomRect);

   // prohibiting default painting     
   e.Handled = true;
}

VB.NET

Imports System.Drawing.Drawing2D
Imports DevExpress.XtraNavBar.ViewInfo

Private Sub NavBarControl1_CustomDrawGroupClientBackground(ByVal sender As Object, _
  ByVal e As CustomDrawObjectEventArgs) Handles NavBarControl1.CustomDrawGroupClientBackground
   ' calculating the top and bottom part rectangles
   Dim Rect As Rectangle = e.RealBounds
   Dim HalfHeight = Rect.Height / 2
   Dim TopRect As New Rectangle(Rect.Left, Rect.Top, Rect.Width, HalfHeight)
   Dim BottomRect As New Rectangle(Rect.Left, Rect.Top + HalfHeight, Rect.Width, HalfHeight)

   ' creating brushes for the top and bottom parts
   Dim OuterColor As Color = Color.White
   Dim InnerColor As Color = Color.LightSkyBlue
   Dim TopBrush As New LinearGradientBrush(TopRect, OuterColor, InnerColor, _
     LinearGradientMode.Vertical)
   Dim BottomBrush As New LinearGradientBrush(BottomRect, InnerColor, OuterColor, _
     LinearGradientMode.Vertical)

   ' filling the top and bottom rectangles with the created brushes
   e.Graphics.FillRectangle(TopBrush, TopRect)
   e.Graphics.FillRectangle(BottomBrush, BottomRect)

   ' prohibiting default painting     
   e.Handled = True
End Sub