How to: Custom Paint the Group's Client Background

• Aug 01, 2019
• 2 minutes to read

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, DevExpress.XtraNavBar.ViewInfo.CustomDrawObjectEventArgs e) {
    // calculate 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);

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

    topBrush.Dispose();
    bottomBrush.Dispose();

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

VB.NET

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

Private Sub NavBarControl1_CustomDrawGroupClientBackground(sender As Object, e As CustomDrawObjectEventArgs) Handles NavBarControl1.CustomDrawGroupClientBackground
    ' calculate 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)

    ' create 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)

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

    TopBrush.Dispose()
    BottomBrush.Dispose()

    ' prohibit default painting     
    e.Handled = True
End Sub