.NET C# Operations with flagged Enumerations

[Flags]
public enum Category
{
Undefined = 0,
AdultsOnly = 1,
Family = 2,
AllInclusive = 4,
City = 8
}
void Main()
{
Category c = Category.AdultsOnly | Category.City; Category[] categories = new Category[2] { Category.AllInclusive, Category.Family};
Category category = categories.Aggregate((i, t) => i | t);
var isThereAtLeastOneMatch = (c & category) != Category.Undefined;
var hasExact = (c & Category.AdultsOnly )== Category.AdultsOnly;
}

asp.net core 2.0 DataFormatString DisplayFor

Propert display formatting that worked in ASP.NET Core 2.0 :

                        <span class="room-price">@(Html.DisplayFor(m => rate.Price))&euro;</span>

[DisplayFormat(DataFormatString = "{0:#,###.00}", ApplyFormatInEditMode =false, NullDisplayText ="")]

public decimal Price { get; set; }       

Important!  Don't use DisplayTextFor!

asp.net mvc core 2.0 validating checkbox

Explains how to force required on checkbox.

    <input type="checkbox" id="TermsOfUseFake">
                        <label for="TermsOfUseFake"><a href='@navLinks.GetSitePageLink(languageGroupId: "TermsOfUse")' target="_blank">@Localizer["Loyalty.RegisterForm.TermsOfUse"]</a></label><br>
                        <input style="width:0px;border:0px!important;padding:0px;" type="text" asp-for="TermsOfUse" />
                        <span asp-validation-for="TermsOfUse" class="text-danger"></span>                        

 $(document).on('change', '#TermsOfUseFake', function () {
                debugger;               
                if ($('#TermsOfUseFake:checked')[0]) {
                    $('#TermsOfUse').val("true");
                }
                else {
                    $('#TermsOfUse').val("");
                }
                $("form#registerForm").validate().element("#TermsOfUse");
            });

ASP.NET MVC Core 2.0 - Resource Key is not compiled from RESX file

Open RESX and change Access Modifier to Public.

Make sure that project builds without error. You can be misled that RESX cant be built while you have compile error.