<RadzenTabs RenderMode="TabRenderMode.Client" @bind-SelectedIndex=@selectedIndex>
    <Tabs>
        <RadzenTabsItem Text="Customers">
            Customers
        </RadzenTabsItem>
        <RadzenTabsItem Text="Orders">
            Orders
        </RadzenTabsItem>
        <RadzenTabsItem Text="Order Details">
            Order Details
        </RadzenTabsItem>
    </Tabs>
</RadzenTabs>

@code {
    int selectedIndex = 0;
}