refactor: 重构代码

Author: ArgoZhang

src/BootstrapBlazor/Components/Tab/Tab.razor.cs

@@ -950,19 +950,26 @@ private async Task OnRefreshAsync()
     {
         // refresh the active tab item
         var item = TabItems.FirstOrDefault(i => i.IsActive);
-        item.Refresh(_cache);
 
-        if (OnToolbarRefreshCallback != null)
+        if (item is not null)
         {
-            await OnToolbarRefreshCallback();
+            await Refresh(item);
         }
     }
 
     /// <summary>
     /// Refresh the tab item method
     /// </summary>
     /// <param name="item"></param>
-    public void Refresh(TabItem item) => item.Refresh(_cache);
+    public async Task Refresh(TabItem item)
+    {
+        item.Refresh(_cache);
+
+        if (OnToolbarRefreshCallback != null)
+        {
+            await OnToolbarRefreshCallback();
+        }
+    }
 
     /// <summary>
     /// <inheritdoc/>

src/BootstrapBlazor/Extensions/TabItemExtensions.cs

@@ -24,9 +24,9 @@ public static RenderFragment RenderContent(this TabItem item, ConcurrentDictiona
         builder.CloseComponent();
     };
 
-    public static void Refresh(this TabItem? item, ConcurrentDictionary<TabItem, TabItemContent> cache)
+    public static void Refresh(this TabItem item, ConcurrentDictionary<TabItem, TabItemContent> cache)
     {
-        if (item is not null && cache.TryGetValue(item, out var content))
+        if (cache.TryGetValue(item, out var content))
         {
             content.Render();
         }