How to implement expandable layout groups in Detail View layout (WinForms)

v19.2+
With XAF v19.2, the new platform-agnostic options - IModelLayoutGroup.IsCollapsibleGroup and IModelLayoutGroup.IsGroupCollapsed - are available to control this behavior for both WinForms and ASP.NET apps. For more information on how it affects the former ASP.NET Application Model options, see this breaking change.

For older versions or custom-tailored implementations when the standard solution is not suitable, consider the options from How do I provide the capability to collapse or expand layout groups and persist their state?

Hi Andrew,

In the simplest way, you can refer to the Access the Layout Control in Code help topic, to access the layout control and set the LayoutGroup.ExpandButtonVisible property for the required layout groups.
This is the code of a controller I used to do this:

C#
using DevExpress.XtraLayout;  
namespace WinSolution.Module {  
    public partial class MyLayoutViewController : ViewController {  
        public MyLayoutViewController() {  
            InitializeComponent();  
            RegisterActions(components);  
            this.TargetObjectType = typeof(WinSolution.Module.MyPerson);  
            this.TargetViewType = DevExpress.ExpressApp.ViewType.DetailView;  
        }  
        protected override void OnActivated() {  
            base.OnActivated();  
            View.ControlsCreated += new EventHandler(View_ControlsCreated);  
        }  
        protected override void OnDeactivating() {  
            base.OnDeactivating();  
            View.ControlsCreated -= new EventHandler(View_ControlsCreated);  
        }  
        void View_ControlsCreated(object sender, EventArgs e) {  
            ((System.Windows.Forms.Control)View.Control).HandleCreated += new EventHandler(MyLayoutViewController_HandleCreated);  
        }  
        void MyLayoutViewController_HandleCreated(object sender, EventArgs e) {  
            DevExpress.XtraLayout.LayoutControl layoutControl = ((DevExpress.XtraLayout.LayoutControl)((DetailView)View).Control);  
            layoutControl.BeginUpdate();  
            try {  
                foreach (object item in layoutControl.Items) {  
                    if (item is LayoutControlGroup) {  
                        ((LayoutControlGroup)item).ExpandButtonVisible = true;  
                        ((LayoutControlGroup)item).Expanded = true;  
                        ((LayoutControlGroup)item).ExpandButtonLocation = DevExpress.Utils.GroupElementLocation.AfterText;  
                        ((LayoutControlGroup)item).ExpandOnDoubleClick = true;  
                    }  
                }  
            } finally {  
                layoutControl.EndUpdate();  
            }  
        }  
    }  
}  

My sample project is also attached. Please let me know if this solution suits your needs. Otherwise, please describe your requirements in more detail.
Thanks,
Dennis

Hello,
The following code can be used to do the same customization:

C#
using System;  
using DevExpress.XtraLayout;  
using DevExpress.ExpressApp;  
using System.Collections.Generic;  
using DevExpress.ExpressApp.Editors;  
using DevExpress.ExpressApp.Win.Layout;  

namespace MainDemo.Module.Win {  
    public class Q101774 : ViewController<DetailView> {  
        private ISupportAppearanceCustomization layoutManager;  
        protected override void OnActivated() {  
            base.OnActivated();  
            layoutManager = (ISupportAppearanceCustomization)View.LayoutManager;  
            layoutManager.CustomizeAppearance += new EventHandler<CustomizeAppearanceEventArgs>(layoutManager_CustomizeAppearance);  
        }  
        private void layoutManager_CustomizeAppearance(object sender, CustomizeAppearanceEventArgs e) {  
            LayoutControlGroup lg = ((WinLayoutItemAppearanceAdapter)e.Item).Item as LayoutControlGroup;  
            if (lg != null) {  
                lg.ExpandButtonVisible = true;  
                lg.Expanded = true;  
                lg.ExpandButtonLocation = DevExpress.Utils.GroupElementLocation.BeforeText;  
                lg.ExpandOnDoubleClick = true;  
            }  
        }  
        protected override void OnDeactivated() {  
            layoutManager.CustomizeAppearance -= new EventHandler<CustomizeAppearanceEventArgs>(layoutManager_CustomizeAppearance);  
            base.OnDeactivated();  
        }  
    }  
}  

Attached is also a small video. It is also possible to extend the application model to save the expandable state.
Thanks,
Dennis