ListView: Expose the IsFrozen property of the group headers

Controls/DataControls/DataControls.UWP/ListView/View/Controls/ListViewGroupHeader.cs

@@ -1,4 +1,5 @@
 using System;
+using System.ComponentModel;
 using Windows.Foundation;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Input;
@@ -16,6 +17,12 @@ namespace Telerik.UI.Xaml.Controls.Data.ListView.Primitives
         public static readonly DependencyProperty IsExpandedProperty =
             DependencyProperty.Register(nameof(IsExpanded), typeof(bool), typeof(ListViewGroupHeader), new PropertyMetadata(true, OnIsExpandedPropertyChanged));
 
+        /// <summary>
+        /// Identifies the IsFrozen dependency property.
+        /// </summary>
+        public static readonly DependencyProperty IsFrozenProperty =
+            DependencyProperty.Register(nameof(IsFrozen), typeof(bool), typeof(ListViewGroupHeader), new PropertyMetadata(false));
+
         /// <inheritdoc/>
         public Rect arrangeRect;
 
@@ -51,6 +58,22 @@ namespace Telerik.UI.Xaml.Controls.Data.ListView.Primitives
             }
         }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether the group header is frozen.
+        /// </summary>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public bool IsFrozen
+        {
+            get
+            {
+                return (bool)this.GetValue(IsFrozenProperty);
+            }
+            set
+            {
+                this.SetValue(IsFrozenProperty, value);
+            }
+        }
+
         Rect IArrangeChild.LayoutSlot
         {
             get
@@ -59,8 +82,6 @@ namespace Telerik.UI.Xaml.Controls.Data.ListView.Primitives
             }
         }
 
-        internal bool IsFrozen { get; set; }
-
         /// <summary>
         /// Gets or sets the <see cref="RadListView"/> owner.
         /// </summary>