services.AddDbContext<ApplicationDbContext>(options =>
      options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")
));

"ConnectionStrings": {
    "ConnectionTemplate": "Data Source=.;Initial Catalog={db_Name};Integrated Security=True",
}

services.AddDbContext<ApplicationDbContext>((serviceProvider, dbContextBuilder) =>
{
   var connectionStringTemplate = Configuration.GetConnectionString("ConnectionTemplate");
   var httpContextAccessor = serviceProvider.GetRequiredService<IHttpContextAccessor>();
   var dbName = httpContextAccessor.HttpContext.Request.Headers["tenantId"].First();
   var connectionString = connectionStringTemplate.Replace("{db_Name}", dbName);
   dbContextBuilder.UseSqlServer(connectionString);
});

window.JsFunctionHelper = {
  blazorSetTitle: function (title) {
    document.title = title;
  }
};

@page "/counter"

<PageTitle Title="@GetPageTitle()" />

<h1>Counter</h1>

<p>Current count: @currentCount</p>

<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>

@code {
    private int currentCount = 0;

    private void IncrementCount()
    {
        currentCount++;
    }

    private string GetPageTitle() => $"Counter ({currentCount})";
}

<Title Value="@title" />
<Meta name="description" content="Modifying the head from a Blazor component." />
<Link href="main.css" rel="stylesheet" />

 PM> install-package Newtonsoft.Json

 var roles = new List<string>
{
   "Admin",
   "User"
};
string json = JsonConvert.SerializeObject(roles, Formatting.Indented);

 var jsonString = JsonConvert.SerializeObject(new
{
   Id =1,
   Name = "Test"
}, Formatting.Indented);

var jsonData = JsonConvert.SerializeObject(new
{
   Id = 1,
   Name = "Test",
   DateTime = DateTime.Now
}, new JsonSerializerSettings
{
   Formatting = Formatting.Indented,
   Converters =
   {
      new JavaScriptDateTimeConverter()
   }
});

 {
  "Id": 1,
  "Name": "Test",
  "DateTime": new Date(1409821985245)
}

using (var stream = File.CreateText(@"c:\output.json"))
{
    var jsonSerializer = new JsonSerializer
   {
      Formatting = Formatting.Indented
   };
   jsonSerializer.Serialize(stream, new
   {
     Id = 1,
     Name = "Test",
     DateTime = DateTime.Now
   });
}

public class User
{
   public int Id { set; get; }
   public string Name { set; get; }
   public DateTime DateTime { set; get; }
}

 var user = JsonConvert.DeserializeObject<User>(jsonData);

var user = JsonConvert.DeserializeObject<User>(jsonData, new JsonSerializerSettings
{
   Converters = {  new JavaScriptDateTimeConverter() }
});

 JsonConvert.PopulateObject(jsonData, user);

var jsonData = JsonConvert.SerializeObject(object, new JsonSerializerSettings
{
   NullValueHandling = NullValueHandling.Ignore,
   Formatting = Formatting.Indented
});

public class Employee
{
    public string Name { set; get; }
}

public class Manager : Employee
{
    public IList<Employee> Reports { set; get; }
}

 var employee = new Employee { Name = "User1" };
var manager1 = new Manager { Name = "User2" };
var manager2 = new Manager { Name = "User3" };
manager1.Reports = new[] { employee, manager2 };
manager2.Reports = new[] { employee };

 var list = JsonConvert.SerializeObject(manager1, Formatting.Indented);

{
  "Reports": [
    {
      "Name": "User1"
    },
    {
      "Reports": [
        {
          "Name": "User1"
        }
      ],
      "Name": "User3"
    }
  ],
  "Name": "User2"
}

var list = JsonConvert.SerializeObject(manager1, new JsonSerializerSettings
{
   Formatting = Formatting.Indented,
   TypeNameHandling = TypeNameHandling.Objects,
   PreserveReferencesHandling = PreserveReferencesHandling.Objects
});
 

{
  "$id": "1",
  "$type": "JsonNetTests.Manager, JsonNetTests",
  "Reports": [
    {
      "$id": "2",
      "$type": "JsonNetTests.Employee, JsonNetTests",
      "Name": "User1"
    },
    {
      "$id": "3",
      "$type": "JsonNetTests.Manager, JsonNetTests",
      "Reports": [
        {
          "$ref": "2"
        }
      ],
      "Name": "User3"
    }
  ],
  "Name": "User2"
}

public class User
{
   public int Id { set; get; }

   [JsonIgnore]
   public string Name { set; get; }

   public DateTime DateTime { set; get; }
}

[JsonProperty(PropertyName = "m_name", NullValueHandling = NullValueHandling.Ignore)]
public string Name { set; get; }

[JsonObject(MemberSerialization.OptIn)]
public class User
{
    public int Id { set; get; }

    [JsonProperty]
    public string Name { set; get; }
 
    public DateTime DateTime { set; get; }
}

[JsonConverter(typeof(JavaScriptDateTimeConverter))]
public DateTime DateTime { set; get; }

public class HtmlColor
{
   public int Red { set; get; }
   public int Green { set; get; }
   public int Blue { set; get; }
}

var colorJson = JsonConvert.SerializeObject(new HtmlColor
{
  Red = 255,
  Green = 0,
  Blue = 0
}, Formatting.Indented);

    public class HtmlColorConverter : JsonConverter
    {

        public override bool CanConvert(Type objectType)
        {
            return objectType == typeof(HtmlColor);
        }

        public override object ReadJson(JsonReader reader, Type objectType,
                                        object existingValue, JsonSerializer serializer)
        {
            throw new NotSupportedException();
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            var color = value as HtmlColor;
            if (color == null)
                return;

            writer.WriteValue("#" + color.Red.ToString("X2")
                + color.Green.ToString("X2") + color.Blue.ToString("X2"));
        }
    }

var colorJson = JsonConvert.SerializeObject(new HtmlColor
{
  Red = 255,
  Green = 0,
  Blue = 0
},  new JsonSerializerSettings
    {
      Formatting = Formatting.Indented,
      Converters = { new HtmlColorConverter() }
    });   

 <input id="pickDate" type="text"/>

 <script type="text/javascript">
  $(function() {
        $("#pickDate").kendoDatePicker();
  });
</script>

 <input id="dateOfBirth" type="text" data-role="datepicker" />

 <!--KendoUI: Web-->
<link href="styles/kendo.common.min.css" rel="stylesheet" type="text/css" />
<link href="styles/kendo.default.min.css" rel="stylesheet" type="text/css" />
<script src="js/jquery.min.js" type="text/javascript"></script>
<script src="js/kendo.web.min.js" type="text/javascript"></script>

<!--KendoUI: DataViz-->
<link href="styles/kendo.dataviz.min.css" rel="stylesheet" type="text/css" />
<script src="js/kendo.dataviz.min.js" type="text/javascript"></script>

<!--KendoUI: Mobile-->
<link href="styles/kendo.mobile.all.min.css" rel="stylesheet" type="text/css" />
<script src="js/kendo.mobile.min.js" type="text/javascript"></script>

 <link href="styles/kendo.common.min.css" rel="stylesheet" type="text/css" />
<link href="styles/kendo.default.min.css" rel="stylesheet" type="text/css" />
<script src="js/jquery.min.js" type="text/javascript"></script>
<script src="js/kendo.all.min.js" type="text/javascript"></script>

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>

    <link href="styles/kendo.common.min.css" rel="stylesheet" type="text/css" />
    <link href="styles/kendo.default.min.css" rel="stylesheet" type="text/css" />
    <script src="js/jquery.min.js" type="text/javascript"></script>
    <script src="js/kendo.all.min.js" type="text/javascript"></script>

    <script type="text/javascript">
        $(function () {
            $("#pickDate").kendoDatePicker();
        });

        $(function () {
            // initialize any widgets in the #container div
            kendo.init($("#container"));
        });
    </script>
</head>
<body>
    <span>
        Pick a date: <input id="pickDate" type="text" />
    </span>

    <div id="container">
        <input id="dateOfBirth" type="text" data-role="datepicker" />
        <div id="colors"
             data-role="colorpalette"
             data-columns="4"
             data-tile-size="{ width: 34, height: 19 }"></div>
    </div>
</body>
</html>

 <script type="text/javascript">
  $(function () {
      $("#pickDate").kendoDatePicker({
              format: "yyyy/MM/dd"
        });
  });
</script>

<input id="dateOfBirth" type="text"
          data-role="datepicker"
          data-format="yyyy/MM/dd" />

    <input id="colorPicker1" />
    <script type="text/javascript">
        $(document).ready(function () {
            $("#colorPicker1").kendoComboBox({
                dataSource: ["Blue", "Green", "Red", "Yellow"]
            });
        });
    </script>

    <input id="colorPicker2" data-role="combobox" data-source='["Blue", "Green", "Red", "Yellow"]' />
    <script type="text/javascript">
        $(document).ready(function () {
            kendo.init($("#colorPicker2"));
        });
    </script>

    <input id="colorPicker3" />
    <script type="text/javascript">
        function onColorChange(e) {
             alert('Color Change!');
        }

        $(document).ready(function () {
            $("#colorPicker3").kendoComboBox({
                dataSource: ["Blue", "Green", "Red", "Yellow"],
                change: onColorChange
            });
        });
    </script>

    <input id="colorPicker4" data-role="combobox"
           data-source='["Blue", "Green", "Red", "Yellow"]'
           data-change="onColorChange" />

    <script type="text/javascript">
        function onColorChange(e) {
            alert('Color Change!');
        }

        $(document).ready(function () {
            kendo.init($("#colorPicker4"));
        });
    </script>

 > ng test --help

 <alert type="success">Alert success!</alert>

import { NO_ERRORS_SCHEMA } from '@angular/core';

describe('AppComponent', () => {
  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [
        AppComponent
      ],
  schemas: [NO_ERRORS_SCHEMA]
    }).compileComponents();
  }));

> ng test -sr
> ng test -w false

 > ng test --code-coverage

 > ng test -sr -cc

 >ng e2e --help

getParagraphText() {
    return element(by.css('app-root h1')).getText();
}

 expect(page.getParagraphText()).toEqual('app works!');

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