Just ran into a minor issue with the DatePicker control.
Using the following line:
<RadzenDatePicker style="width: 100%;" Name="ReqDT" DateFormat="d" @bind-Value="inputData.ReqDT" ReadOnly="@(CurrentPageMode!=PageModes.DataEntry)" />
When I set my PageMode to true, the control TEXT does go into Read Only mode, but the Drop Down Calendar control is still active and the user can click on the calendar and change the date.