GroupControl.CustomDrawCaption Event

Allows you to custom paint the caption region.

Namespace: DevExpress.XtraEditors

Assembly: DevExpress.Utils.v23.2.dll

NuGet Packages: DevExpress.Utils, DevExpress.Wpf.Core

Declaration

C#

[DXCategory("Appearance")]
public virtual event GroupCaptionCustomDrawEventHandler CustomDrawCaption

VB.NET

<DXCategory("Appearance")>
Public Overridable Event CustomDrawCaption As GroupCaptionCustomDrawEventHandler

Event Data

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

Property	Description
Cache	Provides access to the drawing surface and a cache of pens, fonts, and brushes. Inherited from ObjectCustomDrawEventArgs.
CaptionBounds	Gets the painted caption’s bounding rectangle.
Graphics	Provides access to the drawing surface. Inherited from ObjectCustomDrawEventArgs.
Handled	Gets or sets whether the event is handled and prevents the default draw operation from being performed. Inherited from ObjectCustomDrawEventArgs.
Info	Gets information on the painted group.
IsDefaultDrawInProgress	Inherited from ObjectCustomDrawEventArgs.
Painter	Provides access to the object that performs paint operations. Inherited from ObjectCustomDrawEventArgs.

The event data class exposes the following methods:

Method	Description
DefaultDraw()	Inherited from ObjectCustomDrawEventArgs.
DefaultDrawBackground()	Performs default painting of the control’s caption background.
DefaultDrawButtons()	Performs default painting of the buttons embedded in the control’s caption.
DefaultDrawImage()	Performs default painting of the control’s caption image.
DefaultDrawText()	Performs default painting of the text in the control’s caption.
DrawHtml(HtmlTemplate, DxHtmlPainterContext, Action<DxHtmlPainterArgs>)	Paints the required HTML template inside an element that raised this event. The context parameter allows you to assign an object that transfers mouse events to template elements. Inherited from ObjectCustomDrawEventArgs.
DrawHtml(HtmlTemplate, Action<DxHtmlPainterArgs>)	Paints the required HTML template inside an element that raised this event. Inherited from ObjectCustomDrawEventArgs.

Remarks

The CustomDrawCaption event allows you to custom paint the caption. Use the GroupCaptionCustomDrawEventArgs.Info event parameter to obtain the caption’s display settings (for instance, the text, button bounds, etc.).

To draw custom information, use the methods provided by the Cache or Graphics event parameter.

When you handle the CustomDrawCaption event, you can invoke the default rendering of the caption or its individual elements with the following methods:

• DefaultDraw - Performs the default rendering of the caption (including all its elements)
• DefaultDrawBackground - Performs the default rendering of the caption’s background.
• DefaultDrawButtons - Performs the default rendering of the caption’s buttons (GroupControl.CustomHeaderButtons)
• DefaultDrawImage - Performs the default rendering of the caption’s image (GroupControl.CaptionImageOptions)
• DefaultDrawText - Performs the default rendering of the tab’s text (GroupControl.Text)

Set the Handled event parameter to true to indicate that you have handled the CustomDrawCaption event and no default painting is required after your event handler is completed. If the event’s Handled parameter is set to false (the default value), the default painting mechanism will automatically be invoked after your custom draw event handler is completed. The default painting mechanism overrides all rendering you may have performed previously.

Example

The following example demonstrates how to handle the GroupControl.CustomDrawCaption event to manually paint a group control’s caption.

The image below shows the result.

C#

using System.Drawing.Drawing2D;
using DevExpress.XtraEditors;
// ...

private void groupControl1_CustomDrawCaption(object sender, GroupCaptionCustomDrawEventArgs e) {
   LinearGradientBrush outerBrush = new LinearGradientBrush(e.CaptionBounds, 
     Color.LightBlue, Color.Blue, LinearGradientMode.Vertical);
   using(outerBrush) {
      e.Cache.FillRectangle(outerBrush, e.CaptionBounds);
   }

   Rectangle innerRect = Rectangle.Inflate(e.CaptionBounds, -3, -3);
   LinearGradientBrush innerBrush = new LinearGradientBrush(innerRect, Color.Blue, 
     Color.LightBlue, LinearGradientMode.Vertical);
   using(innerBrush) {
      e.Cache.FillRectangle(innerBrush, e.CaptionBounds);
   }

   StringFormat outStrFormat = new StringFormat();
   outStrFormat.Alignment = StringAlignment.Center;
   outStrFormat.LineAlignment = StringAlignment.Center;
   e.Cache.DrawString(e.Info.Caption, e.Info.AppearanceCaption.Font, 
     e.Cache.GetSolidBrush(Color.White), innerRect, outStrFormat);

   e.Handled = true;
}

VB.NET

Imports System.Drawing.Drawing2D
Imports DevExpress.XtraEditors
' ...

Private Sub GroupControl1_CustomDrawCaption(ByVal sender As Object, _
ByVal e As GroupCaptionCustomDrawEventArgs) _
Handles GroupControl1.CustomDrawCaption
   Dim outerBrush As LinearGradientBrush = New LinearGradientBrush(e.CaptionBounds, _
     Color.LightBlue, Color.Blue, LinearGradientMode.Vertical)
   e.Cache.FillRectangle(outerBrush, e.CaptionBounds)
   outerBrush.Dispose()

   Dim innerRect As Rectangle = Rectangle.Inflate(e.CaptionBounds, -3, -3)
   Dim innerBrush As LinearGradientBrush = New LinearGradientBrush(innerRect, _
     Color.Blue, Color.LightBlue, LinearGradientMode.Vertical)
   e.Cache.FillRectangle(innerBrush, e.CaptionBounds)
   innerBrush.Dispose()

   Dim textRect As New RectangleF(innerRect.Left, innerRect.Top, _
     innerRect.Width, innerRect.Height)
   Dim outStrFormat As StringFormat = New StringFormat()
   outStrFormat.Alignment = StringAlignment.Center
   outStrFormat.LineAlignment = StringAlignment.Center
   e.Cache.DrawString(e.Info.Caption, e.Info.AppearanceCaption.Font, _
     e.Cache.GetSolidBrush(Color.White), textRect, outStrFormat)

   e.Handled = True
End Sub