Fixed Select All bug.

Refactored `OnWinSubViewLayout` to add null checks for `_header`
to ensure safety and prevent runtime exceptions. Simplified
"Select All" and "Select None" logic by replacing manual
iteration with `_listView?.MarkAll` calls and added comments
to address a `Terminal.Gui` bug requiring explicit redraws.

Removed default `Ctrl-A` keybinding from `_listView` to allow
custom handling in the status bar. Updated `LangVersion` in
`Microsoft.PowerShell.ConsoleGuiTools.csproj` to `preview` to
enable preview language features. Fixed formatting in the
`ProjectReference` element for consistency.

Author: tig

src/Microsoft.PowerShell.ConsoleGuiTools/ConsoleGui.cs

@@ -119,7 +119,8 @@ void OnWinSubViewLayout(object? sender, EventArgs e)
         {
             CalculateColumnWidths(gridHeaders);
 
-            _header!.Text = GridViewHelpers.GetPaddedString(gridHeaders, _gridViewDetails!.ListViewOffset,
+            if (_header is not null)
+                _header.Text = GridViewHelpers.GetPaddedString(gridHeaders, _gridViewDetails!.ListViewOffset,
                 _gridViewDetails.ListViewColumnWidths);
             UpdateDisplayStrings(_listViewSource);
             ApplyFilter();
@@ -269,19 +270,15 @@ private void AddStatusBar(Window win, bool visible)
         {
             shortcuts.Add(new Shortcut(Key.A.WithCtrl, "Select All", () =>
             {
-                // This selects only the items that match the Filter
-                var gvds = _listView!.Source as GridViewDataSource;
-                gvds!.GridViewRowList.ForEach(i => i.IsMarked = true);
-                _listView.SetNeedsDraw();
+                _listView?.MarkAll(true);
+                _listView?.SetNeedsDraw(); // Bug in Terminal.Gui where MarkAll doesn't refresh display
             }));
 
             // Ctrl-D is commonly used in GUIs for select-none 
             shortcuts.Add(new Shortcut(Key.D.WithCtrl, "Select None", () =>
             {
-                // This un-selects only the items that match the Filter
-                var gvds = _listView!.Source as GridViewDataSource;
-                gvds!.GridViewRowList.ForEach(i => i.IsMarked = false);
-                _listView.SetNeedsDraw();
+                _listView?.MarkAll(false);
+                _listView?.SetNeedsDraw(); // Bug in Terminal.Gui where MarkAll doesn't refresh display
             }));
         }
 
@@ -481,6 +478,9 @@ private void AddListView(Window win)
 
         _listView.SelectedItem = 0;
 
+        // ListView captures Ctrl-A (select all) - we handle this in the status bar
+        _listView.KeyBindings.Remove(Key.A.WithCtrl);
+
         win.Add(_listView);
     }
 

src/Microsoft.PowerShell.ConsoleGuiTools/Microsoft.PowerShell.ConsoleGuiTools.csproj

@@ -2,7 +2,7 @@
     <Import Project="..\..\ConsoleGuiTools.Common.props" />
     <PropertyGroup>
         <TargetFramework>net8.0</TargetFramework>
-        <LangVersion>latest</LangVersion>
+        <LangVersion>preview</LangVersion>
         <Nullable>enable</Nullable>
     </PropertyGroup>
 
@@ -23,7 +23,7 @@
     </ItemGroup>
 
     <ItemGroup>
-        <ProjectReference Include ="../Microsoft.PowerShell.OutGridView.Models/Microsoft.PowerShell.OutGridView.Models.csproj" />
+        <ProjectReference Include="../Microsoft.PowerShell.OutGridView.Models/Microsoft.PowerShell.OutGridView.Models.csproj" />
     </ItemGroup>
 
     <ItemGroup>