You'll need to use some simple Javascript:
@Html.CheckBoxFor(model => model.Lockuntil, new { @class = "rb", data_toggle = "hide-element", data_target = "#datepicker17" })
@Html.LabelFor(model => model.Lockuntil, new { @class = "form-check-label" })
@Html.TextBoxFor(model => model.DateColumn, new { id = "datepicker17" })
$(function(){
var toggleHideElement = function(chk){
var target = $(chk.getAttribute("data-target"));
if (chk.checked) {
target.removeClass("d-none").attr("aria-hidden", "false");
}
else {
target.addClass("d-none").attr("aria-hidden", "true");
}
};
$(document).on("change", "input:checkbox[data-toggle='hide-element']", function(){ toggleHideElement(this); });
$("input:checkbox[data-toggle='hide-element']").each(function(){ toggleHideElement(this); });
});