重构代码以改进查询逻辑和异步处理

- 将 `<Indicator Type="@status"/>` 替换为 `<Indicator Type="@type"/>`。
- 在 `ServiceItem.razor.cs` 文件中，添加了 `using Microsoft.EntityFrameworkCore;` 引用。
- 将 `private EventType status { get; set; }` 更改为 `private EventType type { get; set; }`。
- 将 `OnParametersSetAsync` 方法改为异步方法，并使用 `await` 关键字。
- 修改了查询逻辑，使用 `OrderByDescending` 和 `FirstOrDefaultAsync` 替代 `MaxBy` 方法。
- 删除了 `return Task.CompletedTask;`。

Components/Home/ServiceItem.razor

@@ -17,12 +17,12 @@
   {
     @if (id is null)
     {
-      <Indicator Type="@status"/>
+      <Indicator Type="@type"/>
     }
     else
     {
       <a class="flex items-center" href="/Event/@id">
-        <Indicator Type="@status"/>
+        <Indicator Type="@type"/>
       </a>
     }
   }

Components/Home/ServiceItem.razor.cs

@@ -3,6 +3,7 @@
 using System.Diagnostics.CodeAnalysis;
 using Event;
 using Microsoft.AspNetCore.Components;
+using Microsoft.EntityFrameworkCore;
 using Services;
 
 public partial class ServiceItem {
@@ -11,25 +12,26 @@ public partial class ServiceItem {
     [EditorRequired]
     public RegionService? RegionService { get; set; }
 
-    private EventType status { get; set; }
+    private EventType type { get; set; }
 
     private bool future { get; set; }
 
     private int? id { get; set; }
 
-    protected override Task OnParametersSetAsync() {
-        var res = this.RegionService.Events
+    protected override async Task OnParametersSetAsync() {
+        var res = await this.db.EventRegionService
+            .Where(x => x.RegionServiceId == this.RegionService.Id)
+            .Select(x => x.Event)
             .Where(x =>
                 (x.Type == EventType.Maintenance || x.End == null) &&
                 x.Status != EventStatus.Completed &&
                 x.Status != EventStatus.Resolved &&
                 x.Status != EventStatus.Cancelled)
-            .MaxBy(x => x.Type);
+            .OrderByDescending(x => x.Type)
+            .FirstOrDefaultAsync();
 
         this.id = res?.Id;
-        this.status = res?.Type ?? default;
+        this.type = res?.Type ?? default;
         this.future = res?.Start.ToUniversalTime() > DateTime.UtcNow;
-
-        return Task.CompletedTask;
     }
 }