CollapsingGroupPanel is a general purpose collapsible container control. CollapsingGroupPanel has a header, a header line, a body, a footer line and a footer. The header can contain a HeaderImage and HeaderText. The location and alignment of the HeaderImage are set using the HeaderImageAlign and HeaderImageLayout properties. The alignment of the HeaderText is set using the HeaderTextAlign property. The height of the header line is specified via the HeaderLineHeight property. Similarly the height of the footer line is specified via the FooterLineHeight property. The footer can contain a FooterImage and FooterText. The location and alignment of the FooterImage is controlled using the FooterImageAlign and FooterImageLayout properties. The alignment of the FooterText is specified using the FooterTextAlign property.

A CollapsingGroupPanel can be collapsed so only the header and possibly footer, depending on the value of the ShowFooterWhenCollapsed property, is visible. CollapseDirection determines if the CollapsingGroupPanel will collapse vertically or horizontally. The CollapseMode property specifies what causes a CollpasingGroupPanel to expand or collapse. If a CollapsingGroupPanel collapses automatically then the CollapsingGroupPanel can be Pinned to prevent it from collapsing.

A CollapsingGroupPanel is an IExtenderProvider for all its child controls. CollapsingGroupPanel adds a Label and TextOnFooter property to all contained controls. The position of the Label relative to the control is set by the LabelPosition property. If the control has TextOnFooter, then this text is displayed on the CollapsingGroupBar footer when the control has input focus. It is also possible to indicate which child control has the input focus by highlighting the control. The appearance of the highlight is controlled with the HighlightStyle property and the colour by the HighlightColor property.

The colour of the CollapsingGroupPanel elements are set using the BodyBorderPen, BodyBrush, BorderPen, FooterBorderPen, FooterBrush, FooterLineBrush, HeaderBorderPen and HeaderLineBrush properties. When the mouse cursor is over a CollapsingGroupPanel it is said to be hot and when the mouse cursor is not over a CollapsingGroupPanel it is said to be cold. The CollapsingGroupPanel can be coloured differently depending on whether it is hot or cold. See BrushDefinition for more information of setting hot and cold colours. The opacity of the watermark is also dependent on whether the CollapsingGroupPanel is hot or cold. The WatermarkOpacity and WatermarkHotOpacity set the cold and hot opacities respectively. The Animate property determines the nature of the transition from cold to hot and hot to cold. If Animate is false then colours and opacities change abruptly. If Animate is true then the transition is a smooth fade.

Note that the CollapsingGroupPanel controls the visibility of its child controls. The child controls are hidden when the panel collapses or if the control intersects the footer or footer line. The child controls are shown when the panel expands or the child control no longer intersects the footer or footer line. Use the Invisible property of the child control to override this behaviour. The Invisible property is a CollapsingGroupPanel provided property. The GetInvisible and SetInvisible methods implement the Invisible property.

System.Object
   System.MarshalByRefObject
      System.ComponentModel.Component
         System.Windows.Forms.Control
            System.Windows.Forms.ScrollableControl
               System.Windows.Forms.ContainerControl
                  ICreate.Controls.Bars.CollapsingGroupPanel

Reference