<input dir="ltr" class="form-control input-validation-error" 
type="email" 
data-val="true" 
data-val-email="'آدرس ایمیل' is not a valid email address." 
data-val-remote="این آدرس ایمیل هم اکنون مورد استفاده‌است" 
data-val-remote-url="/Home/ValidateUniqueEmail" 
data-val-required="'آدرس ایمیل' must not be empty." 
id="Email" 
name="Email" 
>

using System.ComponentModel.DataAnnotations;

namespace FluentValidationSample.Models
{
    public class UserModel
    {
        [Display(Name = "نام کاربری")]
        public string Username { get; set; }

        [Display(Name = "سن")]
        public int Age { get; set; }

        [Display(Name = "سابقه کار")]
        public int Experience { get; set; }

        [DataType(DataType.EmailAddress)]
        [Display(Name = "آدرس ایمیل")]
        public string Email { get; set; }
    }
}

using System.Linq;

namespace FluentValidationSample.Services
{
    public interface IUsersService
    {
        bool IsUniqueEmail(string emailAddress);
    }

    public class UsersService : IUsersService
    {
        public bool IsUniqueEmail(string emailAddress)
        {
            string[] registedEmails = {
                "email@site.com",
                "test@gmail.com"
            };
            return !registedEmails.Contains(emailAddress);
        }
    }
}

namespace FluentValidationSample.Web
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddScoped<IUsersService, UsersService>();

using FluentValidation.Validators;
using FluentValidationSample.Services;

namespace FluentValidationSample.ModelsValidations
{
    public class UniqueEmailValidator : PropertyValidator
    {
        private readonly IUsersService _usersService;

        public UniqueEmailValidator(IUsersService usersService)
                : base("این آدرس ایمیل هم اکنون مورد استفاده‌است")
        {
            _usersService = usersService;
        }

        protected override bool IsValid(PropertyValidatorContext context)
        {
            return context.PropertyValue != null &&
                    _usersService.IsUniqueEmail((string)context.PropertyValue);
        }
    }
}

using FluentValidation;
using FluentValidationSample.Services;

namespace FluentValidationSample.ModelsValidations
{
    public static class CustomValidatorExtensions
    {
        public static IRuleBuilderOptions<T, string> UniqueEmail<T>(
            this IRuleBuilder<T, string> ruleBuilder, IUsersService usersService)
        {
            return ruleBuilder.SetValidator(new UniqueEmailValidator(usersService));
        }
    }
}

using FluentValidation;
using FluentValidationSample.Models;
using FluentValidationSample.Services;

namespace FluentValidationSample.ModelsValidations
{
    public class UserModelValidator : AbstractValidator<UserModel>
    {
        public UserModelValidator(IUsersService usersService)
        {
            RuleFor(x => x.Username).NotNull();
            RuleFor(x => x.Age).NotNull();
            RuleFor(x => x.Experience).LowerThan(nameof(UserModel.Age)).NotNull();
            RuleFor(x => x.Email).EmailAddress().NotNull().UniqueEmail(usersService);
        }
    }
}

using FluentValidation;
using FluentValidation.AspNetCore;
using FluentValidation.Internal;
using FluentValidation.Resources;
using FluentValidation.Validators;
using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;

namespace FluentValidationSample.ModelsValidations
{
    public class RemoteClientValidator : ClientValidatorBase
    {
        public string RemoteUrl { set; get; }

        public RemoteClientValidator(PropertyRule rule, IPropertyValidator validator) :
            base(rule, validator)
        {
        }

        public override void AddValidation(ClientModelValidationContext context)
        {
            MergeAttribute(context.Attributes, "data-val", "true");
            MergeAttribute(context.Attributes, "data-val-remote", GetErrorMessage(context));
            MergeAttribute(context.Attributes, "data-val-remote-url", RemoteUrl);
        }

        private string GetErrorMessage(ClientModelValidationContext context)
        {
            var formatter = ValidatorOptions.MessageFormatterFactory().AppendPropertyName(Rule.GetDisplayName());
            string messageTemplate;
            try
            {
                messageTemplate = Validator.Options.ErrorMessageSource.GetString(null);
            }
            catch (FluentValidationMessageFormatException)
            {
                messageTemplate = ValidatorOptions.LanguageManager.GetStringForValidator<NotEmptyValidator>();
            }
            return formatter.BuildMessage(messageTemplate);
        }
    }
}

<input dir="ltr" class="form-control input-validation-error" 
type="email" 
data-val="true" 
data-val-email="'آدرس ایمیل' is not a valid email address." 
data-val-remote="این آدرس ایمیل هم اکنون مورد استفاده‌است" 
data-val-remote-url="/Home/ValidateUniqueEmail" 
data-val-required="'آدرس ایمیل' must not be empty." 
id="Email" 
name="Email" 
>

namespace FluentValidationSample.Web
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddScoped<IUsersService, UsersService>();

            services.AddControllersWithViews().AddFluentValidation(
                fv =>
                {
                    fv.RegisterValidatorsFromAssembly(Assembly.GetExecutingAssembly());
                    fv.RegisterValidatorsFromAssemblyContaining<RegisterModelValidator>();
                    fv.RunDefaultMvcValidationAfterFluentValidationExecutes = false;

                    fv.ConfigureClientsideValidation(clientSideValidation =>
                    {
                        // ...

                        clientSideValidation.Add(
                            validatorType: typeof(UniqueEmailValidator),
                            factory: (context, rule, validator) =>
                                        new RemoteClientValidator(rule, validator)
                                        {
                                            RemoteUrl = "/Home/ValidateUniqueEmail"
                                        });
                    });
                }
            );
        }

namespace FluentValidationSample.Web.Controllers
{
    public class HomeController : Controller
    {
        private readonly IUsersService _usersService;

        public HomeController(IUsersService usersService)
        {
            _usersService = usersService;
        }

         // ...

        public IActionResult ValidateUniqueEmail(string email)
        {
            return Ok(_usersService.IsUniqueEmail(email));
        }
    }
}

<script src="~/lib/jquery/dist/jquery.min.js"></script>
<script src="~/lib/bootstrap/dist/js/bootstrap.bundle.min.js"></script>
<script src="~/lib/jquery-validation/dist/jquery.validate.js"></script>
<script src="~/lib/jquery-validation-unobtrusive/jquery.validate.unobtrusive.js"></script>
<script src="~/js/site.js" asp-append-version="true"></script>

public async Task<List<FeedItem>> GetFeedItems(DateTime date) {
  var feed = "http://planet.xamarin.com/feed/";
  var response = await httpClient.GetStringAsync(feed);
  var items = await ParseFeedAsync(response);
  return items.Where(item => item.Published.Date == date).ToList();
}

<?xml version="1.0" encoding="UTF-8"?>
<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
            xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
            x:Class="MyApp.MainPage">
    <TabbedPage.Children>
        <ContentPage Title="Profile" Icon="Profile.png">
            <StackLayout Spacing="20" Padding="20"
                         VerticalOptions="Center">
                <Entry Placeholder="Username"
                       Text="{Binding Username}"/>
                <Entry Placeholder="Password"
                       Text="{Binding Password}"
                       IsPassword="true"/>
                <Button Text="Login" TextColor="White"
                        BackgroundColor="#77D065"
                        Command="{Binding LoginCommand}"/>
            </StackLayout>
        </ContentPage>
        <ContentPage Title="Settings" Icon="Settings.png">
            <!-- Settings -->
        </ContentPage>
    </TabbedPage.Children>
</TabbedPage>

GitHub Issues

The GitHub Issues integration allows you to search and reference your issues from the commit message box in VS, in response to this suggestion ticket. You can reference an issue or a pull request by typing # or clicking on the # button in the lower right side of the commit message text box. If you weren't already authenticated to access related issues, you will now be prompted to sign in to take advantage of this feature.

Line Unstaging

To continue improving our line-staging (aka interactive staging) feature, we've added unstage. You can now use the tool tip option to unstage changes, line by line, as requested here Unstage individual lines and hunks in a file - 4 votes

Arm64

We continue to build native support for Arm64 on Windows 11 for the most popular developer scenarios. We now support the .NET Multi-platform App UI (MAUI) workload on Arm64 Visual Studio.

C++

• Available as a preview feature, you can now view Unreal Engine logs without leaving VS. To see the logs from the Unreal Engine Editor, click View > Other Windows > UE Log. To filter your logs, click on the "Categories" or "Verbosity" dropdowns. Since this is an experimental feature, feedback is greatly appreciated.
• You can now import STM32CubeIDE projects for embedded development within Visual Studio with File > Open > Import STM32CubeIDE project. This generates a CMake project with device flashing and debugging settings for STLink. You must have the STM32CubeIDE installed with the board support package for your device. More details available here.
• You can use the new CMake Debugger to debug your CMake scripts at build time. You can set breakpoints based on filenames, line numbers, and when CMake errors are triggered. Additionally, you can view call stacks of filenames and watch defined variables. Currently, this only works with bundled CMake, and projects targeting WSL or remote machines are not supported yet. We are actively working to add more support to the CMake debugger, and feedback is greatly appreciated. 

This is the eighth of a series of posts on ASP .NET Core in 2019. In this series, we’ll cover 26 topics over a span of 26 weeks from January through June 2019, titled A-Z of ASP .NET Core! 

1. Introduction
2. Installing LINQPad
3. Beginning with LINQPad
4. LINQPad Basics
5. Querying Databases with LINQ-to-SQL
6. LINQPad as a Code Scratchpad
7. General Summary
8. General Conclusions about LINQPad
9. Appendix 

ImageSharp, ImageSharp.Drawing, and ImageSharp.Web will all be dual licensed under a AGPLv3/Commercial license. The AGPLv3 license will come with exceptions which allow bundling the code alongside all well known open source licenses (Apache 2.0, MIT etc). Any projects seen as direct competition (Imaging SDKs) will not be able to utilize that exception.