refactor: rewrite the way to create context menu for selected commits

- `DataGrid` always returns selected items in order. There's no need to sort commits
- Use callback instead of passing the `DataGrid` to ViewModels.

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/ViewModels/Histories.cs

@@ -299,39 +299,30 @@ public void CheckoutBranchByCommit(Models.Commit commit)
             }
         }
 
-        public ContextMenu MakeContextMenu(DataGrid list)
+        public ContextMenu CreateContextMenuForSelectedCommits(List<Models.Commit> selected, Action<Models.Commit> onAddSelected)
         {
             var current = _repo.CurrentBranch;
-            if (current == null || list.SelectedItems == null)
+            if (current == null)
                 return null;
 
-            if (list.SelectedItems.Count > 1)
+            if (selected.Count > 1)
             {
-                var selected = new List<Models.Commit>();
                 var canCherryPick = true;
                 var canMerge = true;
 
-                foreach (var item in list.SelectedItems)
+                foreach (var c in selected)
                 {
-                    if (item is Models.Commit c)
+                    if (c.IsMerged)
                     {
-                        selected.Add(c);
-
-                        if (c.IsMerged)
-                        {
-                            canMerge = false;
-                            canCherryPick = false;
-                        }
-                        else if (c.Parents.Count > 1)
-                        {
-                            canCherryPick = false;
-                        }
+                        canMerge = false;
+                        canCherryPick = false;
+                    }
+                    else if (c.Parents.Count > 1)
+                    {
+                        canCherryPick = false;
                     }
                 }
 
-                // Sort selected commits in order.
-                selected.Sort((l, r) => _commits.IndexOf(r) - _commits.IndexOf(l));
-
                 var multipleMenu = new ContextMenu();
 
                 if (!_repo.IsBare)
@@ -449,7 +440,7 @@ public ContextMenu MakeContextMenu(DataGrid list)
                 return multipleMenu;
             }
 
-            var commit = (list.SelectedItem as Models.Commit)!;
+            var commit = selected[0];
             var menu = new ContextMenu();
             var tags = new List<Models.Tag>();
 
@@ -699,7 +690,7 @@ public ContextMenu MakeContextMenu(DataGrid list)
                     }
                     else
                     {
-                        list.SelectedItems.Add(head);
+                        onAddSelected?.Invoke(head);
                     }
 
                     e.Handled = true;

src/Views/Histories.axaml.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Text;
 
 using Avalonia;
@@ -198,11 +199,21 @@ private void OnCommitListSelectionChanged(object _, SelectionChangedEventArgs e)
         private void OnCommitListContextRequested(object sender, ContextRequestedEventArgs e)
         {
             if (DataContext is ViewModels.Histories histories &&
-                sender is DataGrid { SelectedItems.Count: > 0 } dataGrid &&
+                sender is DataGrid { SelectedItems: { } selected } dataGrid &&
                 e.Source is Control { DataContext: Models.Commit })
             {
-                var menu = histories.MakeContextMenu(dataGrid);
-                menu?.Open(dataGrid);
+                var commits = new List<Models.Commit>();
+                for (var i = selected.Count - 1; i >= 0; i--)
+                {
+                    if (selected[i] is Models.Commit c)
+                        commits.Add(c);
+                }
+
+                if (selected.Count > 0)
+                {
+                    var menu = histories.CreateContextMenuForSelectedCommits(commits, c => dataGrid.SelectedItems.Add(c));
+                    menu?.Open(dataGrid);
+                }
             }
 
             e.Handled = true;