code_style: use normalized path for _gitCommonDir

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

Author: love-linger

src/App.axaml.cs

@@ -748,10 +748,17 @@ private void Check4Update(bool manually = false)
 
         private void ShowSelfUpdateResult(object data)
         {
-            Dispatcher.UIThread.Post(async () =>
+            try
             {
-                await ShowDialog(new ViewModels.SelfUpdate { Data = data });
-            });
+                Dispatcher.UIThread.Invoke(async () =>
+                {
+                    await ShowDialog(new ViewModels.SelfUpdate { Data = data });
+                });
+            }
+            catch
+            {
+                // Ignore exceptions.
+            }
         }
 
         private string FixFontFamilyName(string input)

src/ViewModels/Repository.cs

@@ -432,10 +432,12 @@ public Repository(bool isBare, string path, string gitDir)
             if (isWorktree)
             {
                 var commonDir = File.ReadAllText(commonDirFile).Trim();
-                if (!Path.IsPathRooted(commonDir))
+                if (Path.IsPathRooted(commonDir))
+                    commonDir = new DirectoryInfo(commonDir).FullName;
+                else
                     commonDir = new DirectoryInfo(Path.Combine(GitDir, commonDir)).FullName;
 
-                _gitCommonDir = commonDir;
+                _gitCommonDir = commonDir.Replace('\\', '/').TrimEnd('/');
             }
             else
             {