How to: Custom Paint Group Captions

Nov 13, 2018
2 minutes to read

The following sample code handles the NavBarControl.CustomDrawGroupCaption event to custom paint the borders around group captions, fill in the background and paint its text. The background is filled in, in various different ways depending upon the state of the group’s caption.

The image below shows the look & feel of group captions in the normal, hot tracked and pressed states, respectively.

C#
VB.NET

csharp

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

private void navBarControl1_CustomDrawGroupCaption(object sender, 
  CustomDrawNavBarElementEventArgs e) {
    Rectangle outerRect = e.RealBounds;
    e.Cache.FillRectangle(Brushes.Orange, outerRect);

    // painting the background
    Rectangle innerRect = outerRect;
    innerRect.Inflate(-1, -1);
    LinearGradientBrush innerBrush;
    if(e.ObjectInfo.State == ObjectState.Hot)
        innerBrush = new LinearGradientBrush(innerRect, Color.PeachPuff, Color.Orange,
            LinearGradientMode.Vertical);
    else if(e.ObjectInfo.State == ObjectState.Normal)
        innerBrush = new LinearGradientBrush(innerRect, Color.Orange, Color.PeachPuff,
            LinearGradientMode.Horizontal);
    else
        innerBrush = new LinearGradientBrush(innerRect, Color.Orange, Color.PeachPuff,
            LinearGradientMode.Vertical);
    using(innerBrush) 
        e.Cache.FillRectangle(innerBrush, innerRect);

    // painting the caption
    using(var outStringFormat = new StringFormat()) {
        outStringFormat.Alignment = StringAlignment.Near;
        outStringFormat.LineAlignment = StringAlignment.Center;
        NavGroupInfoArgs info = e.ObjectInfo as NavGroupInfoArgs;
        e.Cache.DrawString(info.Group.Caption, e.Appearance.Font, Brushes.White,
            innerRect, outStringFormat);
    }

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

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

Private Sub NavBarControl1_CustomDrawGroupCaption(ByVal sender As Object, _
  ByVal e As CustomDrawNavBarElementEventArgs) Handles NavBarControl1.CustomDrawGroupCaption
    Dim outerRect As Rectangle = e.RealBounds
    e.Cache.FillRectangle(Brushes.Orange, outerRect)

    ' painting the background
    Dim innerRect As Rectangle = outerRect
    innerRect.Inflate(-1, -1)
    Dim innerBrush As LinearGradientBrush
    If e.ObjectInfo.State = ObjectState.Hot Then
        innerBrush = New LinearGradientBrush(innerRect, Color.PeachPuff, Color.Orange, LinearGradientMode.Vertical)
    ElseIf e.ObjectInfo.State = ObjectState.Normal Then
        innerBrush = New LinearGradientBrush(innerRect, Color.Orange, Color.PeachPuff, LinearGradientMode.Horizontal)
    Else
        innerBrush = New LinearGradientBrush(innerRect, Color.Orange, Color.PeachPuff, LinearGradientMode.Vertical)
    End If
    Using innerBrush
        e.Cache.FillRectangle(innerBrush, innerRect)
    End Using

    ' painting the caption
    Using outStringFormat = New StringFormat()
        outStringFormat.Alignment = StringAlignment.Near
        outStringFormat.LineAlignment = StringAlignment.Center
        Dim info As NavGroupInfoArgs = TryCast(e.ObjectInfo, NavGroupInfoArgs)
        e.Cache.DrawString(info.Group.Caption, e.Appearance.Font, Brushes.White, innerRect, outStringFormat)
    End Using

    ' prohibiting default painting
    e.Handled = True
End Sub