doc: 更新 RadioList 示例

Author: ArgoZhang

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

@@ -13,6 +13,12 @@
     <ConsoleLogger @ref="Logger" />
 </DemoBlock>
 
+<DemoBlock Title="@Localizer["RadiosAutoSelectFirstWhenValueIsNullTitle"]"
+           Introduction="@Localizer["RadiosAutoSelectFirstWhenValueIsNullIntro"]"
+           Name="AutoSelectFirstWhenValueIsNull">
+    <RadioList TValue="string" Items="@AutoSelectValues" AutoSelectFirstWhenValueIsNull="false" />
+</DemoBlock>
+
 <DemoBlock Title="@Localizer["RadiosDisableTitle"]"
            Introduction='@Localizer["RadiosDisableIntro"]'
            Name="Disable">

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

@@ -16,6 +16,9 @@ public sealed partial class Radios
     [NotNull]
     private IEnumerable<SelectedItem>? DemoValues { get; set; }
 
+    [NotNull]
+    private IEnumerable<SelectedItem>? AutoSelectValues { get; set; }
+
     [NotNull]
     private IEnumerable<SelectedItem>? DisableValues { get; set; }
 
@@ -70,6 +73,12 @@ protected override void OnInitialized()
             new("2", Localizer["RadiosItem2"])
         };
 
+        AutoSelectValues = new List<SelectedItem>(2)
+        {
+            new("1", Localizer["RadiosItem1"]),
+            new("2", Localizer["RadiosItem2"])
+        };
+
         DisableValues = new List<SelectedItem>(2)
         {
             new("1", Localizer["RadiosItem1"]),
@@ -177,6 +186,14 @@ private AttributeItem[] GetAttributes() =>
             Type = "IEnumerable<TItem>",
             ValueList = " — ",
             DefaultValue = "—"
+        },
+        new()
+        {
+            Name = "AutoSelectFirstWhenValueIsNull",
+            Description = Localizer["RadiosAutoSelectFirstWhenValueIsNull"],
+            Type = "bool",
+            ValueList = "true|false",
+            DefaultValue = "true"
         }
     ];