Add dropdown component

src/Connected.Components/Components/Dropdown.razor

@@ -0,0 +1,48 @@
+@typeparam T;
+@inherits Connected.Models.InputBase;
+
+<div class="@InputFieldClassList">
+   <select type="textarea" @onfocus="(()=> Open())" @onblur="(()=> Close())">
+      @if (SelectedItems.Any())
+      {
+         <option selected>
+            @foreach (var item in SelectedItems)
+            {
+               @SelectedValueTemplate?.Invoke(item)
+            }
+         </option>
+      }
+   </select>
+
+
+
+   <span class="highlight"></span><span class="bar"></span>
+   <label class="label-animated">@Label</label>
+   <div class="input-helper-text">@HelperText</div>
+   <div class="input-error-text">@ErrorText</div>
+   <span class="input-glyph-wraper">
+      <span class="input-glyph button">
+         <Glyph SVG="@Icons.Material.Outlined.Cancel" class="icon-root svg-icon" Click="_ => { SelectedItems.Clear(); Close(); }" />
+      </span>
+      <span class="input-glyph">
+         <Glyph SVG="@Icons.Material.Filled.ArrowDropDown" class="icon-root svg-icon icon-size-md" Click="()=> Toggle()" />
+      </span>
+      <span class="input-glyph error">
+         <Glyph SVG="@Icons.Material.Outlined.ErrorOutline" class="icon-root svg-icon" />
+      </span>
+   </span>
+
+   <TransitionAnimator TransitionDuration="5000" TransitionInClass="drop-down fade-in" TransitionOutClass="drop-down fade-out" Visible=@DropdownOpen>
+      <div class="backdrop d-sm-none">
+      </div>
+      <div class="dropdown-menu">
+         @foreach (var item in Items)
+         {
+            <div class="dropdown-item @(IsItemSelected(item)?"active":"")"
+              @onclick="(async () => await OptionSelected(item))">
+               @OptionTemplate?.Invoke(item)
+            </div>
+         }
+      </div>
+   </TransitionAnimator>
+</div>

src/Connected.Components/Components/Dropdown.razor.cs

@@ -0,0 +1,112 @@
+using Microsoft.AspNetCore.Components;
+using System.Collections.ObjectModel;
+using Connected.Models;
+using System.Collections.Immutable;
+
+namespace Connected.Components;
+
+public partial class Dropdown<T> : InputBase, IAsyncDisposable
+{
+	[Parameter, EditorRequired]
+	public ObservableCollection<T> Items { get; set; } = new ObservableCollection<T>();
+
+	[Parameter]
+	public RenderFragment<T>? OptionTemplate { get; set; }
+
+	[Parameter]
+	public RenderFragment<T>? SelectedValueTemplate { get; set; }
+
+	[Parameter, EditorRequired]
+	public Func<T, string> ItemToKey { get; set; } = default!;
+
+	[Parameter]
+	public ObservableCollection<T> SelectedItems { get; set; } = new();
+
+	[Parameter]
+	public EventCallback<ObservableCollection<T>> SelectedItemsChanged { get; set; }
+
+	[Parameter]
+	public bool AllowMultiple { get; set; }
+
+	private bool DropdownOpen { get; set; }
+
+	private bool IsItemSelected(T item)
+	{
+		return SelectedItems.Contains(item);
+	}
+
+	public void Open()
+	{
+		DropdownOpen = true;
+	}
+
+	public void Close()
+	{
+		DropdownOpen = false;
+	}
+
+	public void Toggle()
+	{
+		DropdownOpen = !DropdownOpen;
+	}
+
+	protected override void OnInitialized()
+	{
+		base.OnInitialized();
+		
+		OptionTemplate ??= (T item) => (builder) =>
+		{
+			builder.OpenElement(0, "div");
+			builder.SetKey(item);
+			builder.AddContent(1, item?.ToString());
+			builder.CloseElement();
+		};
+
+		SelectedValueTemplate ??= (T item) => (builder) =>
+		{
+			builder.OpenElement(0, "span");
+			builder.SetKey(item);
+			builder.AddContent(1, item?.ToString());
+			builder.CloseElement();
+		};
+	}
+	protected override void OnParametersSet()
+	{
+		base.OnParametersSet();
+
+		Items.CollectionChanged += CollectionChanged;
+		SelectedItems.CollectionChanged += CollectionChanged;
+	}
+
+	private void CollectionChanged(object? sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
+	{
+		if (sender == SelectedItems)
+			SelectedItemsChanged.InvokeAsync(SelectedItems);
+
+		StateHasChanged();
+	}
+
+	private async Task OptionSelected(T item)
+	{
+		if (AllowMultiple)
+		{
+			if (SelectedItems.Contains(item))
+			{
+				SelectedItems.Remove(item);
+				return;
+			}
+		}
+		else
+		{
+			SelectedItems.Clear();
+		}
+
+		SelectedItems.Add(item);
+	}
+
+	public async ValueTask DisposeAsync()
+	{
+		Items.CollectionChanged -= CollectionChanged;
+		SelectedItems.CollectionChanged -= CollectionChanged;
+	}
+}