doc: 更新示例文档

Author: ArgoZhang

src/BootstrapBlazor.Server/Components/Samples/Selects.razor

@@ -452,22 +452,24 @@
     <p class="code-label">1. 使用 OnQueryAsync 作为数据源</p>
     <div class="row mb-3">
         <div class="col-6">
-            <Select IsVirtualize="true" OnQueryAsync="OnQueryAsync" @bind-Value="VirtualItem1"
+            <Select IsVirtualize="true" OnQueryAsync="OnQueryAsync" @bind-Value="_virtualItem1"
+                    DefaultVirtualizeItemText="@VirtualItemText1"
                     ShowSearch="_showSearch" IsClearable="_isClearable"></Select>
         </div>
         <div class="col-6">
-            <Display TValue="string" Value="@VirtualItem1?.Text"></Display>
+            <Display TValue="int" Value="@_virtualItem1"></Display>
         </div>
     </div>
 
     <p class="code-label">2. 使用 Items 作为数据源</p>
     <div class="row">
         <div class="col-6">
-            <Select IsVirtualize="true" Items="VirtualItems" @bind-Value="VirtualItem2"
+            <Select IsVirtualize="true" Items="VirtualItems" @bind-Value="_virtualItem2"
+                    DefaultVirtualizeItemText="@VirtualItemText2"
                     ShowSearch="_showSearch" IsClearable="_isClearable"></Select>
         </div>
         <div class="col-6">
-            <Display TValue="string" Value="@VirtualItem2?.Text"></Display>
+            <Display TValue="int" Value="@_virtualItem2"></Display>
         </div>
     </div>
 </DemoBlock>

src/BootstrapBlazor.Server/Components/Samples/Selects.razor.cs

@@ -1,4 +1,4 @@
-// Licensed to the .NET Foundation under one or more agreements.
+// Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the Apache 2.0 License
 // See the LICENSE file in the project root for more information.
 // Maintainer: Argo Zhang(argo@live.ca) Website: https://www.blazor.zone
@@ -28,11 +28,13 @@ public sealed partial class Selects
         new SelectedItem ("Shanghai", "上海")
     };
 
-    private IEnumerable<SelectedItem> VirtualItems => Foos.Select(i => new SelectedItem(i.Name!, i.Name!)).ToList();
+    private IEnumerable<SelectedItem> VirtualItems => Foos.Select(i => new SelectedItem(i.Id.ToString(), i.Name!)).ToList();
 
-    private SelectedItem? VirtualItem1 { get; set; }
+    private int _virtualItem1 = 2;
+    private string? VirtualItemText1 => VirtualItems.FirstOrDefault(i => i.Value == "2")?.Text;
 
-    private SelectedItem? VirtualItem2 { get; set; }
+    private int _virtualItem2 = 2;
+    private string? VirtualItemText2 => VirtualItems.FirstOrDefault(i => i.Value == "2")?.Text;
 
     [NotNull]
     private List<Foo>? Foos { get; set; }