Adjust project structure

src/Shared/HandyControl_Shared/Tools/Helper/VisualHelper.cs

@@ -0,0 +1,54 @@
+using System.Linq;
+using System.Windows;
+using System.Windows.Media;
+
+namespace HandyControl.Tools
+{
+    public class VisualHelper
+    {
+        internal static VisualStateGroup TryGetVisualStateGroup(DependencyObject d, string groupName)
+        {
+            var root = GetImplementationRoot(d);
+            if (root == null)
+            {
+                return null;
+            }
+
+            return VisualStateManager
+                .GetVisualStateGroups(root)?
+                .OfType<VisualStateGroup>()
+                .FirstOrDefault(group => string.CompareOrdinal(groupName, group.Name) == 0);
+        }
+
+        internal static FrameworkElement GetImplementationRoot(DependencyObject d)
+        {
+            return 1 == VisualTreeHelper.GetChildrenCount(d)
+                ? VisualTreeHelper.GetChild(d, 0) as FrameworkElement
+                : null;
+        }
+
+        internal static T GetChild<T>(DependencyObject d) where T : DependencyObject
+        {
+            if (d is T t)
+            {
+                return t;
+            }
+
+            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(d); i++)
+            {
+                var child = VisualTreeHelper.GetChild(d, i);
+
+                var result = GetChild<T>(child);
+                if (result != null) return result;
+            }
+
+            return default(T);
+        }
+
+        /// <summary>
+        ///     获取当前应用中处于激活的一个窗口
+        /// </summary>
+        /// <returns></returns>
+        public static Window GetActiveWindow() => Application.Current.Windows.OfType<Window>().SingleOrDefault(x => x.IsActive);
+    }
+}