What are the controls in WPF for displaying data in DateTime format?

Question

WPF

I tried to use the WPF Toolkit DateTimePicker, but when I try to get the BindingExpression and update the source data, the value ValuePropertyis lost somewhere.

BindingExpression expression = Control.GetBindingExpression(DateTimePicker.ValueProperty);

Then I add this one BindingExpressionto others in List<BindingExpression>, well, I update the source:

foreach (var exp in expressions)
{
    exp.UpdateSource();
}

As a result, there is no source data.
Actually, with native controls, in particular with TextBox, there are no such problems.
From here and two questions:
How to solve the problem with BindingExpression in WPF Toolkit DateTimePicker?
What are the free controls in WPF for displaying data in DateTime format?