// ...

builder.Services.AddRazorComponents()
    .AddInteractiveServerComponents()
    .AddInteractiveWebAssemblyComponents();

// ...

app.MapRazorComponents<App>()
    .AddInteractiveServerRenderMode()
    .AddInteractiveWebAssemblyRenderMode()
    .AddAdditionalAssemblies(typeof(Counter).Assembly);

@rendermode InteractiveAuto

<Banner @rendermode="@InteractiveAuto" Text="Hello"/>

@using static Microsoft.AspNetCore.Components.Web.RenderMode

public class CaptchaController : Controller
    {
        public ActionResult CaptchaImage(string prefix, bool noisy = true)
        {
            var rand = new Random((int)DateTime.Now.Ticks);
            //generate new question
            int a = rand.Next(10, 99);
            int b = rand.Next(0, 9);
            var captcha = string.Format("{0} + {1} = ?", a, b);

            //store answer
            Session["Captcha" + prefix] = a + b;

            //image stream
            FileContentResult img = null;

            using (var mem = new MemoryStream())
            using (var bmp = new Bitmap(130, 30))
            using (var gfx = Graphics.FromImage((Image)bmp))
            {
                gfx.TextRenderingHint = TextRenderingHint.ClearTypeGridFit;
                gfx.SmoothingMode = SmoothingMode.AntiAlias;
                gfx.FillRectangle(Brushes.White, new Rectangle(0, 0, bmp.Width, bmp.Height));

                //add noise
                if (noisy)
                {
                    int i, r, x, y;
                    var pen = new Pen(Color.Yellow);
                    for (i = 1; i < 10; i++)
                    {
                        pen.Color = Color.FromArgb(
                        (rand.Next(0, 255)),
                        (rand.Next(0, 255)),
                        (rand.Next(0, 255)));

                        r = rand.Next(0, (130 / 3));
                        x = rand.Next(0, 130);
                        y = rand.Next(0, 30);

                        gfx.DrawEllipse(pen, x - r, y - r, r, r);
                    }
                }

                //add question
                gfx.DrawString(captcha, new Font("Tahoma", 15), Brushes.Gray, 2, 3);

                //render as Jpeg
                bmp.Save(mem, System.Drawing.Imaging.ImageFormat.Jpeg);
                img = this.File(mem.GetBuffer(), "image/Jpeg");
            }

            return img;
        }

[Required(ErrorMessage = "لطفا {0} را وارد کنید")]
         [Display(Name = "حاصل جمع")]
         public string Captcha { get; set; }

<div class="form-group">
                        <input type="button" value="" id="refresh" />

                        @Html.LabelFor(model => model.Captcha)

                        <img alt="Captcha" id="imgcpatcha" src="@Url.Action("CaptchaImage","Captcha")" style="" />
                    </div>

<script type="text/javascript">
    $(function () {
        $('#refresh').click(function () {


            $.ajax({
                url: '@Url.Action("CaptchaImage","Captcha")',
                type: "GET",
                data: null
            })
            .done(function (functionResult) {
                $("#imgcpatcha").attr("src", "/Captcha/CaptchaImage?" + functionResult);
            });

        });
    });
</script>

if (Session["Captcha"] == null || Session["Captcha"].ToString() != model.Captcha)
            {
                ModelState.AddModelError("Captcha", "مجموع اشتباه است");
            }

  $('#refresh').click(function () {
         
            var d = new Date();
            $("#imgcpatcha").attr("src", "Captcha/CaptchaImage?" + d.getTime());

        });

import { HttpClient } from "@angular/common/http";
import { Injectable } from "@angular/core";

@Injectable()
export class AppConfigService {

    private config: IAppConfig;

    constructor(private http: HttpClient) { }

    loadClientConfig(): Promise<any> {
        return this.http.get<IAppConfig>("assets/client-config.json")
            .toPromise()
            .then(config => {
                this.config = config;
                console.log("Config", this.config);
            })
            .catch(err => {
                return Promise.reject(err);
            });
    }

    get configuration(): IAppConfig {
        if (!this.config) {
            throw new Error("Attempted to access configuration property before configuration data was loaded.");
        }
        return this.config;
    }
}

export interface IAppConfig {
    apiEndpoint: string;
    loginPath: string;
    logoutPath: string;
    refreshTokenPath: string;
    accessTokenObjectKey: string;
    refreshTokenObjectKey: string;
    adminRoleName: string;
}

import { NgModule, Optional, SkipSelf, APP_INITIALIZER } from "@angular/core";
import { CommonModule } from "@angular/common";
import { RouterModule } from "@angular/router";
import { HTTP_INTERCEPTORS } from "@angular/common/http";

// import RxJs needed operators only once
import "./services/rxjs-operators";

import { HeaderComponent } from "./component/header/header.component";
import { AuthGuard } from "./services/auth.guard";
import { AuthInterceptor } from "./services/auth.interceptor";
import { AuthService } from "./services/auth.service";
import { AppConfigService } from "./services/app-config.service";
import { BrowserStorageService } from "./services/browser-storage.service";


@NgModule({
    imports: [CommonModule, RouterModule],
    exports: [
        // components that are used in app.component.ts will be listed here.
        HeaderComponent
    ],
    declarations: [
        // components that are used in app.component.ts will be listed here.
        HeaderComponent
    ],
    providers: [
        // global singleton services of the whole app will be listed here.
        BrowserStorageService,
        AppConfigService,
        AuthService,
        AuthGuard,
        {
            provide: HTTP_INTERCEPTORS,
            useClass: AuthInterceptor,
            multi: true
        },
        {
            provide: APP_INITIALIZER,
            useFactory: (config: AppConfigService) => () => config.loadClientConfig(),
            deps: [AppConfigService ],
            multi: true
        }
    ]
})
export class CoreModule {
    constructor( @Optional() @SkipSelf() core: CoreModule) {
        if (core) {
            throw new Error("CoreModule should be imported ONLY in AppModule.");
        }
    }
}

 PM> Install-Package Mvc4CodeTemplatesCSharp

<#
    if (!mvcHost.IsContentPage) {
#>
<script src="~/Scripts/jquery-1.9.1.min.js"></script>
<script src="~/Scripts/jquery.validate.min.js"></script>
<script src="~/Scripts/jquery.validate.unobtrusive.min.js"></script>

<#
    }
}
#>
@using (Html.BeginForm()) {
    @Html.ValidationSummary(true, null, new { @class = "alert alert-error alert-block" })

    <fieldset class="form-horizontal">
        <legend><#= mvcHost.ViewDataType.Name #></legend>

<#
foreach (ModelProperty property in GetModelProperties(mvcHost.ViewDataType)) {
    if (!property.IsPrimaryKey && !property.IsReadOnly && property.Scaffold) {
#>
        <div class="control-group">
<#
        if (property.IsForeignKey) {
#>
            @Html.LabelFor(model => model.<#= property.Name #>, "<#= property.AssociationName #>",new {@class="control-label"})
<#
        } else {
#>
            @Html.LabelFor(model => model.<#= property.Name #>,new {@class="control-label"})
<#
        }
#>
        
           <div class="controls">
<#
        if (property.IsForeignKey) {
#>
            @Html.DropDownList("<#= property.Name #>", String.Empty)
<#
        } else {
#>
            @Html.EditorFor(model => model.<#= property.Name #>)
<#
        }
#>
            @Html.ValidationMessageFor(model => model.<#= property.Name #>,null,new{@class="help-inline"})
</div>
        </div>

<#
    }
}
#>
<div class="form-actions">
            <button type="submit" class="btn btn-primary">ارسال</button>
            <button class="btn">لغو</button>
          </div>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>
<#
if(mvcHost.IsContentPage && mvcHost.ReferenceScriptLibraries) {
#>

@section JavaScript {    

}

    <div class="container">
        <h4 class="alert alert-info">
            فرم‌های مودال بوت استرپ 3</h4>
        <div class="row">
            <a data-toggle="modal" href="#myModal" class="btn btn-primary">نمایش صفحه مودال</a>
            <div class="modal" id="myModal">
                <div class="modal-dialog">
                    <div class="modal-content">
                        <div class="modal-header">
                            <button type="button" class="close" data-dismiss="modal" aria-hidden="true">
                                ×</button>
                            <h4 class="modal-title">
                                عنوان</h4>
                        </div>
                        <div class="modal-body">
                            محتوای صفحه در اینجا
                        </div>
                        <div class="modal-footer">
                            <a href="#" data-dismiss="modal" class="btn">بستن</a> <a href="#" class="btn btn-primary">
                                ذخیره سازی تغییرات</a>
                        </div>
                    </div>
                </div>
            </div>
        </div>
        <!-- end row -->
    </div>
    <!-- /container -->

$('#myModal').modal({
   show: true,
   remote: '/myNestedContent'
});

<a data-toggle="modal" class="btn btn-primary" href="@renderModalPartialViewUrl" data-target="#myModal">Click me</a>
 <div class="modal fade" id="myModal" tabindex="-1" role="dialog"></div>

<div class="modal" id="myModal">

<body>
    <div class="container">
        <h2>Medical Questionnaire</h2>
        <form>
            <fieldset>
                <legend>Owner Info</legend>
                <div>
                    <label for="ownername">Owner name</label>
                    <input type="text" id="ownername" placeholder="Your Name">
                </div>
                <div>
                    <label for="owneremail">Email address</label>
                    <input type="email" id="owneremail" aria-describedby="emailHelp"
                        placeholder="Enter email">
                    <small id="emailHelp">We'll never share your email</small>
                </div>
            </fieldset>

            <fieldset>
                <legend>Pet Info</legend>
                <div>
                    <label for="petname">Pet name</label>
                    <input type="text" id="petname" placeholder="Your Pet's name">
                </div>
                <div>
                    <label for="pettype">Pet type</label>
                    <select id="pettype">
                        <option>Choose</option>
                        <option value="cat">Dog</option>
                        <option value="cat">Cat</option>
                        <option value="bird">Other</option>
                    </select>
                </div>
                <div>
                    <label for="reasonforvisit">Reason for today's visit</label>
                    <textarea id="reasonforvisit" rows="3"></textarea>
                </div>
                <div>
                    <label>Has your pet been spayed or neutered?</label>
                    <label><input type="radio" name="spayneut" value="yes"
                            checked> Yes</label>
                    <label><input type="radio" name="spayneut" value="no"> No</label>
                </div>
                <div>
                    <label>Has the pet had any of the following in the past 30
                        days</label>
                    <label><input type="checkbox"> Abdominal pain</label>
                    <label><input type="checkbox"> Lack of appetite</label>
                    <label><input type="checkbox"> Weakness</label>
                </div>
            </fieldset>
            <button type="submit">Submit</button>
        </form>

    </div><!-- content container -->
</body>

<div class="form-check">
    <label class="form-check-label">
        <input class="form-check-input" type="checkbox">
        Lack of appetite
    </label>
</div>

<div class="form-group">
    <label class="d-block">Has your pet been spayed or
        neutered?</label>
    <div class="form-check form-check-inline">
        <label class="form-check-label">
            <input class="form-check-input" type="radio" name="spayneut"
                   value="yes" checked>
            Yes
        </label>
    </div>
    <div class="form-check form-check-inline">
        <label class="form-check-label">
            <input class="form-check-input" type="radio" name="spayneut"
                   value="no"> No
        </label>
    </div>
</div>

<div class="form-group">
    <label for="owneremail" class="text-success">Email address</label>
    <input class="form-control is-valid" type="email" id="owneremail"
        aria-describedby="emailHelp" placeholder="Enter email">
    <small class="form-text text-muted" id="emailHelp">We'll
        never share your email</small>
    <div class="valid-feedback">
        Looks good!
    </div>
</div>

<body>
    <div class="container">
        <h2>Medical Questionnaire</h2>
        <form>
            <fieldset class="form-group">
                <legend>Owner Info</legend>
                <div class="form-group row">
                    <label class="form-control-label col-md-2 col-form-label text-md-right"
                        for="ownername">Owner</label>
                    <div class="col-md-10">
                        <input class="form-control" type="text" id="ownername"
                            placeholder="Your Name">
                    </div>
                </div>
                <div class="form-group row">
                    <label class="form-control-label col-md-2 col-form-label text-md-right"
                        for="owneremail">Address</label>
                    <div class="col-md-10">
                        <input class="form-control" type="text" id="owneremail"
                            placeholder="Address">
                    </div>
                </div>
                <div class="form-group row">
                    <div class="form-group col-6 offset-md-2">
                        <label class="form-control-label sr-only" for="ownercity">City</label>
                        <input class="form-control" type="text" id="ownercity"
                            placeholder="City">
                    </div>
                    <div class="form-group col-md-4 col-6">
                        <label class="form-control-label sr-only" for="ownerzip">Zip</label>
                        <input class="form-control" type="text" id="ownerzip"
                            placeholder="Zip">
                    </div>
                </div>

                <div class="form-group row">
                    <div class="offset-md-2 col-md-10">
                        <button class="btn btn-primary" type="submit">Submit</button>
                    </div>
                </div>
            </fieldset>
        </form>
    </div>
</body>

                <div class="form-group row">
                    <label class="form-control-label col-md-2 col-form-label text-md-right"
                        for="ownername">Owner</label>
                    <div class="col-md-10">
                        <input class="form-control" type="text" id="ownername"
                            placeholder="Your Name">
                    </div>
                </div>

<div class="form-group row">
   <div class="form-group col-6 offset-md-2">
   <label class="form-control-label sr-only" for="ownercity">City</label>
   <input class="form-control" type="text" id="ownercity"placeholder="City">
</div>

<div class="form-group row">
    <div class="offset-md-2 col-md-10">
        <button class="btn btn-primary" type="submit">Submit</button>
    </div>
</div>

<div class="form-group">
    <label class="form-control-label" for="donationamt">
        Donation Amount
    </label>
    <div class="input-group">
        <div class="input-group-prepend">
            <span class="input-group-text">$</span>
        </div>
        <input type="text" class="form-control" id="donationamt"
            placeholder="Amount">
        <div class="input-group-append">
            <span class="input-group-text">.00</span>
        </div>
    </div>
</div>

    <nav class="navbar bg-dark navbar-dark navbar-expand-sm">
        <div class="container">
            <div class="navbar-brand d-none d-sm-inline-block">
                Wisdom Pet Medicine
            </div>
            <div class="navbar-nav mr-auto">
                <a class="nav-item nav-link active" href="#">Home</a>
                <a class="nav-item nav-link" href="#">Mission</a>
                <a class="nav-item nav-link" href="#">Services</a>
                <a class="nav-item nav-link" href="#">Staff</a>
                <a class="nav-item nav-link" href="#">Testimonials</a>
            </div>
            <form class="form-inline d-none d-md-inline-block">
                <div class="input-group">
                    <label for="search" class="form-control-label sr-only"></label>
                    <input type="text" id="search" class="form-control"
                        placeholder="Search ...">
                    <div class="input-group-append">
                        <button class="btn btn-outline-light" type="submit">Go</button>
                    </div>
                </div>
            </form>
        </div>
    </nav>

public class Student{
    [Display(Name="نام خانوادگی")]
    public string FamilyName { get; set;}
}

<label asp-for="FamilyName"></label>

[Display(
     Name = "نام خانوادگی",
     Description = "بهتر است فقط در اینجا نام خانوادگی شخص وارد شود")]
public string FamilyName{ get; set; }

<span asp-description-for="FamilyName"></span>

<span>بهتر است فقط در اینجا نام خانوادگی شخص وارد شود</span>

using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Razor.TagHelpers;

[HtmlTargetElement("div", Attributes = ForAttributeName)]
[HtmlTargetElement("p", Attributes = ForAttributeName)]
[HtmlTargetElement("span", Attributes = ForAttributeName)]
public sealed class DescriptionForTagHelper : TagHelper
{
    private const string ForAttributeName = "asp-description-for";

    [HtmlAttributeName(ForAttributeName)] 
    public ModelExpression For { get; set; } = default!;

    public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
    {
        if (context == null)
        {
            throw new ArgumentNullException(nameof(context));
        }

        if (output == null)
        {
            throw new ArgumentNullException(nameof(output));
        }

        var description = For.Metadata.Description;
        if (description != null)
        {
            // Do not update the content if another tag helper
            // targeting this element has already done so.
            if (!output.IsContentModified)
            {
                var childContent = await output.GetChildContentAsync();
                if (childContent.IsEmptyOrWhiteSpace)
                {
                    output.Content.SetHtmlContent(description);
                }
                else
                {
                    output.Content.SetHtmlContent(childContent);
                }
            }
        }
    }
}