[Framework + Core] Feature: Add support for adding multiple grid items (#105)

For plugin developers: Adds a new method to the IObservatoryCore interface to add multiple grid items in 1 call -- which only invokes the UI thread once (and potentially only scrolls to bottom once) providing a small performance improvement and providing some modest convenience.

ObservatoryCore/PluginManagement/PluginCore.cs

@@ -105,21 +105,28 @@ namespace Observatory.PluginManagement
                 //Hacky removal of original empty object if one was used to populate columns
                 if (worker.PluginUI.DataGrid.Count == 2)
                 {
-                    bool allNull = true;
+                    if (FirstRowIsAllNull(worker))
-                    Type itemType = worker.PluginUI.DataGrid[0].GetType();
-                    foreach (var property in itemType.GetProperties())
-                    {
-                        if (property.GetValue(worker.PluginUI.DataGrid[0], null) != null)
-                        {
-                            allNull = false;
-                            break;
-                        }
-                    }
-
-                    if (allNull)
                         worker.PluginUI.DataGrid.RemoveAt(0);
                 }
+            });
+        }
 
+        /// <summary>
+        /// Adds multiple items to the datagrid on UI thread to ensure visual update.
+        /// </summary>
+        /// <param name="worker"></param>
+        /// <param name="items"></param>
+        public void AddGridItems(IObservatoryWorker worker, IEnumerable<object> items)
+        {
+            Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(() =>
+            {
+                var cleanEmptyRow = worker.PluginUI.DataGrid.Count == 1 && FirstRowIsAllNull(worker) && items.Count() > 0;
+                foreach (var item in items)
+                {
+                    worker.PluginUI.DataGrid.Add(item);
+                }
+                if (cleanEmptyRow)
+                    worker.PluginUI.DataGrid.RemoveAt(0);
             });
         }
 
@@ -175,5 +182,21 @@ namespace Observatory.PluginManagement
         {
             NativePopup.CloseAll();
         }
+
+        private static bool FirstRowIsAllNull(IObservatoryWorker worker)
+        {
+            bool allNull = true;
+            Type itemType = worker.PluginUI.DataGrid[0].GetType();
+            foreach (var property in itemType.GetProperties())
+            {
+                if (property.GetValue(worker.PluginUI.DataGrid[0], null) != null)
+                {
+                    allNull = false;
+                    break;
+                }
+            }
+
+            return allNull;
+        }
     }
 }

ObservatoryFramework/Interfaces.cs

@@ -156,6 +156,13 @@ namespace Observatory.Framework.Interfaces
         /// <param name="item">Grid item to be added. Object type should match original template item used to create the grid.</param>
         public void AddGridItem(IObservatoryWorker worker, object item);
 
+        /// <summary>
+        /// Add multiple items to the bottom of the basic UI grid.
+        /// </summary>
+        /// <param name="worker">Reference to the calling plugin's worker interface.</param>
+        /// <param name="items">Grid items to be added. Object types should match original template item used to create the grid.</param>
+        public void AddGridItems(IObservatoryWorker worker, IEnumerable<object> items);
+
         /// <summary>
         /// Clears basic UI grid, removing all items.
         /// </summary>