Porting System.Windows.Forms.Design.ListViewSubItemCollectionEditor

src/System.Design/src/System.Design.Forwards.cs

@@ -9,6 +9,7 @@
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.ImageCollectionEditor))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.ImageIndexEditor))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.ListControlStringCollectionEditor))]
+[assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.ListViewSubItemCollectionEditor))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.StringArrayEditor))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.StringCollectionEditor))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.TabPageCollectionEditor))]

src/System.Windows.Forms.Design.Editors/src/Resources/SR.resx

@@ -181,6 +181,9 @@
   <data name="imageFileDescription" xml:space="preserve">
     <value>All image files</value>
   </data>
+  <data name="ListViewSubItemBaseName" xml:space="preserve">
+    <value>ListViewSubItem</value>
+  </data>
   <data name="metafileFileDescription" xml:space="preserve">
     <value>Metafiles</value>
   </data>

src/System.Windows.Forms.Design.Editors/src/System/Windows/Forms/Design/ListViewSubItemCollectionEditor.cs

@@ -0,0 +1,113 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Collections;
+using System.ComponentModel;
+using System.ComponentModel.Design;
+
+namespace System.Windows.Forms.Design
+{
+    /// <summary>
+    ///  Provides an editor for a ListView subitems collection.
+    /// </summary>
+    internal class ListViewSubItemCollectionEditor : CollectionEditor
+    {
+        private static int _count = 0;
+        private ListViewItem.ListViewSubItem _firstSubItem = null;
+
+        /// <summary>
+        ///  Initializes a new instance of the <see cref='System.Windows.Forms.Design.ListViewSubItemCollectionEditor'/> class.
+        /// </summary>
+        public ListViewSubItemCollectionEditor(Type type) : base(type)
+        { }
+
+        /// <summary>
+        ///  Creates an instance of the specified type in the collection.
+        /// </summary>
+        protected override object CreateInstance(Type type)
+        {
+            object instance = base.CreateInstance(type);
+
+            // slap in a default site-like name
+            if (instance is ListViewItem.ListViewSubItem)
+            {
+                ((ListViewItem.ListViewSubItem)instance).Name = SR.ListViewSubItemBaseName + _count++;
+            }
+
+            return instance;
+        }
+
+        /// <summary>
+        ///  Retrieves the display text for the given list sub item.
+        /// </summary>
+        protected override string GetDisplayText(object value)
+        {
+            if (value == null)
+            {
+                return string.Empty;
+            }
+
+            string text;
+
+            PropertyDescriptor prop = TypeDescriptor.GetDefaultProperty(CollectionType);
+
+            if (prop != null && prop.PropertyType == typeof(string))
+            {
+                text = (string)prop.GetValue(value);
+
+                if (text != null && text.Length > 0)
+                {
+                    return text;
+                }
+            }
+
+            text = TypeDescriptor.GetConverter(value).ConvertToString(value);
+
+            if (text == null || text.Length == 0)
+            {
+                text = value.GetType().Name;
+            }
+
+            return text;
+        }
+
+        protected override object[] GetItems(object editValue)
+        {
+            // take the fist sub item out of the collection
+            ListViewItem.ListViewSubItemCollection subItemsColl = (ListViewItem.ListViewSubItemCollection)editValue;
+
+            // add all the other sub items
+            object[] values = new object[subItemsColl.Count];
+            ((ICollection)subItemsColl).CopyTo(values, 0);
+
+            if (values.Length > 0)
+            {
+                // save the first sub item
+                _firstSubItem = subItemsColl[0];
+
+                // now return the rest.
+                object[] subValues = new object[values.Length - 1];
+                Array.Copy(values, 1, subValues, 0, subValues.Length);
+                values = subValues;
+            }
+
+            return values;
+        }
+
+        protected override object SetItems(object editValue, object[] value)
+        {
+            IList list = editValue as IList;
+            list.Clear();
+
+            list.Add(_firstSubItem);
+
+            for (int i = 0; i < value.Length; i++)
+            {
+                list.Add(value[i]);
+            }
+
+            return editValue;
+        }
+    }
+}

src/System.Windows.Forms.Design.Editors/tests/UnitTests/EnsureEditorsTests.cs

@@ -94,7 +94,7 @@ public void EnsureUITypeEditorForType(Type type, Type expectedEditorType)
         [InlineData(typeof(ListViewItem), "ImageIndex", typeof(ImageIndexEditor))]
         [InlineData(typeof(ListViewItem), "ImageKey", typeof(ImageIndexEditor))]
         [InlineData(typeof(ListViewItem), "StateImageIndex", typeof(ImageIndexEditor))]
-        //[InlineData(typeof(ListViewItem), "SubItems", typeof(ListViewSubItemCollectionEditor))]
+        [InlineData(typeof(ListViewItem), "SubItems", typeof(ListViewSubItemCollectionEditor))]
         //[InlineData(typeof(MaskedTextBox), "Mask", typeof(MaskPropertyEditor))]
         //[InlineData(typeof(MaskedTextBox), "Text", typeof(MaskedTextBoxTextEditor))]
         [InlineData(typeof(NotifyIcon), "BalloonTipText", typeof(MultilineStringEditor))]