source: extensions/PiwigoLib/PiwigoWpf/Helper/AppHelper.cs @ 7160

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;
using System.Windows;
using System.Diagnostics.CodeAnalysis;

namespace Com.Piwigo.Wpf.Helper
{
    public class AppHelper
    {
        private static bool? _isInDesignMode;

        /// <summary>
        /// Gets a value indicating whether the control is in design mode (running in Blend
        /// or Visual Studio).
        /// </summary>
        public static bool IsInDesignModeStatic
        {
            get
            {
                if (!_isInDesignMode.HasValue)
                {
                    var prop = DesignerProperties.IsInDesignModeProperty;
                    _isInDesignMode
                        = (bool)DependencyPropertyDescriptor
                        .FromProperty(prop, typeof(FrameworkElement))
                        .Metadata.DefaultValue;
                }

                return _isInDesignMode.Value;
            }
        }

        /// <summary>
        /// Gets a value indicating whether the control is in design mode (running under Blend
        /// or Visual Studio).
        /// </summary>
        [SuppressMessage(
            "Microsoft.Performance",
            "CA1822:MarkMembersAsStatic",
            Justification = "Non static member needed for data binding")]
        public bool IsInDesignMode
        {
            get
            {
                return IsInDesignModeStatic;
            }
        }

    }

}