LT-21129: Fix crash in Bulk Edit Phoneme Features preview

Src/Common/Controls/XMLViews/BulkEditBar.cs

@@ -417,6 +417,7 @@ public void UpdateColumnList()
 		{
 			CheckDisposed();
 
+			PreUpdateColumnList();
 			// ClickCopy.ClickCopyTabPageSettings/SaveSettings()/CommitClickChanges()
 			// could possibly change m_hvoSelected when we're not ready, so save current.
 			// see comment on LT-4768 below.
@@ -437,6 +438,7 @@ public void UpdateColumnList()
 			m_operationsTabControl_SelectedIndexChanged(this, new EventArgs());
 			m_hvoSelected = oldSelected;
 			ResumeRecordListRowChanges();
+			PostUpdateColumnList();
 		}
 
 		/// <summary>
@@ -1748,6 +1750,26 @@ protected virtual void ShowPreviewItems(ProgressState state)
 										 XMLViewsDataCache.ktagItemEnabled, state);
 		}
 
+		/// <summary>
+		/// UpdateColumnList() will Dispose all the BulkEditItems and re-create them. So any
+		/// derived class that needs to do something before or after that should override the Pre
+		/// or Post method.
+		/// </summary>
+		protected virtual void PreUpdateColumnList()
+		{
+
+		}
+
+		/// <summary>
+		/// UpdateColumnList() will Dispose all the BulkEditItems and re-create them. So any
+		/// derived class that needs to do something before or after that should override the Pre
+		/// or Post method.
+		/// </summary>
+		protected virtual void PostUpdateColumnList()
+		{
+
+		}
+
 		internal void ClearPreview()
 		{
 			HandlePreviewOrSuggestTask(DoClearPreviewTask);

Src/FdoUi/PhonologicalFeatureEditor.cs

@@ -657,6 +657,9 @@ private bool IsItemEligible(ISilDataAccess sda, int hvo, ICmObject selectedObjec
 	/// </summary>
 	public class BulkEditBarPhonologicalFeatures : BulkEditBar
 	{
+		private string m_currentFeatDefnAbbr = null;
+		private int m_currentSelectedHvo = 0;
+
 		/// ------------------------------------------------------------------------------------
 		/// <summary>
 		/// Create one
@@ -755,6 +758,40 @@ protected override void ShowPreviewItems(ProgressState state)
 				}
 			}
 		}
+
+		/// <summary>
+		/// UpdateColumnList() will Dispose all the BulkEditItems and re-create them.  The
+		/// currently displayed PhonologicalFeatureEditor stores it's SelectedHvo. Store it
+		/// here so we can restore it after the new one is created.
+		/// </summary>
+		protected override void PreUpdateColumnList()
+		{
+			BulkEditItem bei = m_beItems[m_itemIndex];
+			if (bei.BulkEditControl is PhonologicalFeatureEditor phonFeatEditor)
+			{
+				m_currentFeatDefnAbbr = phonFeatEditor.FeatDefnAbbr;
+				m_currentSelectedHvo = phonFeatEditor.SelectedHvo;
+			}
+		}
+
+		/// <summary>
+		/// UpdateColumnList() will Dispose all the BulkEditItems and re-create them.  The
+		/// currently displayed PhonologicalFeatureEditor stores it's SelectedHvo. Restore it
+		/// here after the new one is created.
+		/// </summary>
+		protected override void PostUpdateColumnList()
+		{
+			BulkEditItem bei = m_beItems[m_itemIndex];
+			if (bei.BulkEditControl is PhonologicalFeatureEditor phonFeatEditor &&
+				phonFeatEditor.FeatDefnAbbr == m_currentFeatDefnAbbr)
+			{
+				phonFeatEditor.SelectedHvo = m_currentSelectedHvo;
+			}
+
+			m_currentFeatDefnAbbr = null;
+			m_currentSelectedHvo = 0;
+		}
+
 		protected override void Dispose(bool disposing)
 		{
 			if (IsDisposed)