Added events and code to copy column widths when switching between grouping grids on TestExplorerControl form

Author: machthree

Rubberduck.Core/UI/UnitTesting/TestExplorerControl.xaml

@@ -626,7 +626,8 @@
                 <controls:GroupingGrid ItemsSource="{Binding Source={StaticResource ResultsByOutcome}}"
                                            SelectedItem="{Binding SelectedTest}"
                                            ShowGroupingItemCount="True"
-                                           Visibility="{Binding GroupByOutcome, Converter={StaticResource BoolToVisibility}}">
+                                           Visibility="{Binding GroupByOutcome, Converter={StaticResource BoolToVisibility}}"
+                                           IsVisibleChanged="ResultsGroupingGrid_IsVisibleChanged">
                     <DataGrid.Columns>
                         <DataGridTemplateColumn Header="{Resx ResxName=Rubberduck.Resources.UnitTesting.TestExplorer, Key=TestExplorer_Outcome}">
                             <DataGridTemplateColumn.CellTemplate>
@@ -645,7 +646,8 @@
                 <controls:GroupingGrid ItemsSource="{Binding Source={StaticResource ResultsByModule}}"
                                            SelectedItem="{Binding SelectedTest}"
                                            ShowGroupingItemCount="True"
-                                           Visibility="{Binding GroupByLocation, Converter={StaticResource BoolToVisibility}}">
+                                           Visibility="{Binding GroupByLocation, Converter={StaticResource BoolToVisibility}}"
+                                           IsVisibleChanged="ResultsGroupingGrid_IsVisibleChanged">
                     <DataGrid.Columns>
                         <DataGridTemplateColumn Header="{Resx ResxName=Rubberduck.Resources.UnitTesting.TestExplorer, Key=TestExplorer_Outcome}">
                             <DataGridTemplateColumn.CellTemplate>
@@ -664,7 +666,8 @@
                 <controls:GroupingGrid ItemsSource="{Binding Source={StaticResource ResultsByCategory}}"
                                            SelectedItem="{Binding SelectedTest}"
                                            ShowGroupingItemCount="True"
-                                           Visibility="{Binding GroupByCategory, Converter={StaticResource BoolToVisibility}}">
+                                           Visibility="{Binding GroupByCategory, Converter={StaticResource BoolToVisibility}}"
+                                           IsVisibleChanged="ResultsGroupingGrid_IsVisibleChanged">
                     <DataGrid.Columns>
                         <DataGridTemplateColumn Header="{Resx ResxName=Rubberduck.Resources.UnitTesting.TestExplorer, Key=TestExplorer_Outcome}">
                             <DataGridTemplateColumn.CellTemplate>

Rubberduck.Core/UI/UnitTesting/TestExplorerControl.xaml.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Windows.Data;
 using System.Windows.Threading;
+using Rubberduck.UI.Controls;
 
 namespace Rubberduck.UI.UnitTesting
 {
@@ -68,5 +69,31 @@ protected virtual void Dispose(bool disposing)
             DataContextChanged -= TestExplorerControl_DataContextChanged;
             _isDisposed = true;
         }
+        private GroupingGrid _newGroupingGrid;
+        private void ResultsGroupingGrid_IsVisibleChanged(object sender, System.Windows.DependencyPropertyChangedEventArgs e)
+        {
+            if (sender is GroupingGrid)
+            {
+                GroupingGrid groupingGrid = (GroupingGrid)sender;
+                // actual height checks that form is visible at this point
+                // don't set up the "new" visible element until we see an object with an actual height
+                if (!((groupingGrid.ActualHeight == 0) && (_newGroupingGrid is null))) // check form elements are actually set up (i.e. not initialising form)
+                {
+                    // this code relies on the new element being made visible before the old is hidden, so we save the new element 
+                    // and then copy column widths from the old now hidden element on the subsequent invocation
+                    if (groupingGrid.IsVisible)
+                        _newGroupingGrid = groupingGrid;
+                    else
+                    {
+                        // copy column widths from previously visible grouping grid to ensure widths are consistent
+                        for (int columnIndex = 0; columnIndex < groupingGrid.Columns.Count; columnIndex++)
+                        {
+                            // copy column widths from current now hidden columns to the new visible columns
+                            _newGroupingGrid.Columns[columnIndex].Width = groupingGrid.Columns[columnIndex].Width;
+                        }
+                    }
+                }
+            }
+        }
     }
 }