I'm using the DatePicker from the WPF ToolKit with a custom style. In my style, I would like to use a ToggleButton instead of the normal button, but this doesn't work without changing two lines of code in DatePicker.cs.
The field for the DropDownButton is defined as
private ButtonBase _dropDownButton;
No problem so far. But in the TemplatePart attribute, the button is not defined as ButtonBase, but as Button instead:
[TemplatePart(Name = DatePicker.ElementButton, Type = typeof(Button))]
Also, in the OnApplyTemplate method, the button is also defined as Button:
_dropDownButton = GetTemplateChild(ElementButton) as Button;
By changing those two lines to ButtonBase, it's also working with a ToggleButton.
Maybe you can change that in future releases?