refactor: 增加多选参数支持

Author: ArgoZhang

src/components/BootstrapBlazor.Region/Components/SelectCity.razor.cs

@@ -9,6 +9,12 @@ namespace BootstrapBlazor.Components;
 /// </summary>
 public partial class SelectCity
 {
+    /// <summary>
+    /// 获得/设置 是否可多选 默认 false 单选
+    /// </summary>
+    [Parameter]
+    public bool IsMultiple { get; set; }
+
     private string? InputId => $"{Id}_input";
 
     private string? ClassString => CssBuilder.Default("select bb-region")
@@ -32,6 +38,10 @@ private async Task OnClearValue()
 
     private void OnSelectCity(string item)
     {
+        if(IsMultiple)
+        {
+
+        }
         if (!_values.Remove(item))
         {
             _values.Add(item);

src/components/BootstrapBlazor.Region/Components/SelectRegionBase.cs

@@ -2,8 +2,6 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 // Website: https://www.blazor.zone or https://argozhang.github.io/
 
-using Microsoft.AspNetCore.Components;
-
 namespace BootstrapBlazor.Components;
 
 /// <summary>