refactor: 增加 DropdownMenu 组件

Author: ArgoZhang

src/BootstrapBlazor/Components/AutoComplete/DropdownMenu.razor

@@ -0,0 +1,21 @@
+@namespace BootstrapBlazor.Components
+
+<ul class="dropdown-menu">
+    @foreach (var item in Rows)
+    {
+        <li @key="item" class="dropdown-item" @onclick="() => OnClick(item)">
+            @if (ItemTemplate == null)
+            {
+                <div>@item</div>
+            }
+            else
+            {
+                @ItemTemplate(item)
+            }
+        </li>
+    }
+    @if (ShowNoDataTip && Rows.Count == 0)
+    {
+        <li class="dropdown-item">@NoDataTip</li>
+    }
+</ul>

src/BootstrapBlazor/Components/AutoComplete/DropdownMenu.razor.cs

@@ -0,0 +1,61 @@
+// 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([email protected]) Website: https://www.blazor.zone
+
+namespace BootstrapBlazor.Components;
+
+/// <summary>
+/// DropdownMenu component
+/// </summary>
+public partial class DropdownMenu
+{
+    /// <summary>
+    /// Get or set the dropdown menu items
+    /// </summary>
+    [Parameter, NotNull, EditorRequired]
+    public List<string>? Rows { get; set; }
+
+    /// <summary>
+    /// Get or set the dropdown menu item template default value is null.
+    /// </summary>
+    [Parameter]
+    public RenderFragment<string>? ItemTemplate { get; set; }
+
+    /// <summary>
+    /// Gets or sets whether to show the no matching data option, default is true
+    /// </summary>
+    [Parameter]
+    public bool ShowNoDataTip { get; set; } = true;
+
+    /// <summary>
+    /// Gets or sets Display prompt message when there is no matching data. The default prompt is "No Data"
+    /// </summary>
+    [Parameter]
+    [NotNull]
+    public string? NoDataTip { get; set; }
+
+    /// <summary>
+    /// Gets or sets Callback method when a candidate item is clicked
+    /// </summary>
+    [Parameter]
+    public Func<string, Task>? OnItemClick { get; set; }
+
+    private Task OnClick(string val)
+    {
+        if (OnItemClick != null)
+        {
+            return OnItemClick.Invoke(val);
+        }
+        return Task.CompletedTask;
+    }
+
+    /// <summary>
+    /// Render method
+    /// </summary>
+    public void Render(List<string> items)
+    {
+        Rows = items;
+        StateHasChanged();
+    }
+}