GroupControl.CustomDrawCaption Event

Allows you to custom paint the caption region.

Namespace: DevExpress.XtraEditors

Assembly: DevExpress.Utils.v20.1.dll

Declaration

[DXCategory("Appearance")]
public virtual event GroupCaptionCustomDrawEventHandler CustomDrawCaption
<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.
Painter Provides access to the object that performs paint operations. 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.

Examples

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.

GroupControl_CustomDrawCaption

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.Graphics.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.Graphics.FillRectangle(innerBrush, e.CaptionBounds);
   }

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

   e.Handled = true;
}
See Also