For a page you can set a attribute in the .razor file like: @attribute [Authorize(Roles = "Admin")]
for a button you can set the Visible or Disabled parameter, depends on what you prefer: <RadzenButton Disabled="@(!Security.IsInRole("Admin"))" Icon="add_circle_outline" style="margin-bottom: 10px" Text="Add" Click="@Button0Click"> </RadzenButton>