Add TabControl & TabPage

Oqtane.Client/Themes/Controls/TabControl.razor

@@ -0,0 +1,43 @@
+@namespace Oqtane.Themes.Controls
+@inherits ThemeControlBase
+
+<CascadingValue Value="this">
+    <div>
+        @foreach (TabPage tabPage in Pages)
+        {
+            <button type="button"
+                    class="btn @GetButtonClass(tabPage)"
+                    @onclick=@( () => ActivatePage(tabPage) )>
+                @tabPage.Text
+            </button>
+        }
+    </div>
+    @ChildContent
+</CascadingValue>
+
+@code {
+    // Next line is needed so we are able to add <TabPage> components inside
+    [Parameter]
+    public RenderFragment ChildContent { get; set; }
+
+    public TabPage ActivePage { get; set; }
+    List<TabPage> Pages = new List<TabPage>();
+
+    internal void AddPage(TabPage tabPage)
+    {
+        Pages.Add(tabPage);
+        if (Pages.Count == 1)
+            ActivePage = tabPage;
+        StateHasChanged();
+    }
+
+    string GetButtonClass(TabPage page)
+    {
+        return page == ActivePage ? "btn-primary" : "btn-secondary";
+    }
+
+    void ActivatePage(TabPage page)
+    {
+        ActivePage = page;
+    }
+}

Oqtane.Client/Themes/Controls/TabPage.razor

@@ -0,0 +1,27 @@
+@namespace Oqtane.Themes.Controls
+@inherits ThemeControlBase
+
+@if (Parent.ActivePage == (TabPage)(object)this)
+{
+    @ChildContent
+}
+
+@code {
+    [CascadingParameter]
+    private TabControl Parent { get; set; }
+
+    [Parameter]
+    public RenderFragment ChildContent { get; set; }
+
+    [Parameter]
+    public string Text { get; set; }
+
+    protected override void OnInitialized()
+    {
+        if (Parent == null)
+            throw new ArgumentNullException(nameof(Parent), "TabPage must exist within a TabControl");
+
+        base.OnInitialized();
+        Parent.AddPage((TabPage)(object)this);
+    }
+}