![7/21/2022 26
JSON Syntax Rules
Data is in name/value pairs
Data is separated by commas
Curly braces hold objects
Square brackets hold arrays
{
"employees":
[
{"firstName":"John", "lastName":"Doe"},
{"firstName":"Anna", "lastName":"Smith"},
{"firstName":"Peter", "lastName":"Jones"}
]
}](https://image.slidesharecdn.com/slot0506-workingwithxmlandjsonserializing-220721084056-59a0c8bc/85/Working-with-XML-and-JSON-Serializing-26-320.jpg)
![7/21/2022 30
JSON Data Types
Array: It is an ordered collection of values and begins with [ (left bracket) and
ends with ] (right bracket). The values of array are separated by ,(comma)
Syntax:
[ value, .......]
Example:
{
"collection" : [
{"id" : 101},
{"id" : 102},
{"id" : 103}
]
}](https://image.slidesharecdn.com/slot0506-workingwithxmlandjsonserializing-220721084056-59a0c8bc/85/Working-with-XML-and-JSON-Serializing-30-320.jpg)
![7/21/2022 38
Json Serialization Behavior
By default, all public properties are serialized. To ignore individual properties,
use the [JsonIgnore] attribute
The default encoder escapes non-ASCII characters, HTML-sensitive characters
within the ASCII-range, and characters that must be escaped according to the
RFC 8259 JSON spec
By default, JSON is minified. To pretty-print the JSON output, set
JsonSerializerOptions.WriteIndented to true
By default, casing of JSON names matches the .NET names. To set the name
of individual properties, we can use the [JsonPropertyName] attribute
By default, fields are ignored (use [JsonInclude] attribute to include fields)](https://image.slidesharecdn.com/slot0506-workingwithxmlandjsonserializing-220721084056-59a0c8bc/85/Working-with-XML-and-JSON-Serializing-38-320.jpg)
![7/21/2022 39
Json Deserialization Behavior
By default, property name matching is case-sensitive
If the JSON contains a value for a read-only property, the value is ignored and
no exception is thrown. Non-public constructors are ignored by the serializer
Deserialization to immutable objects or read-only properties is supported
By default, enums are supported as numbers. We can serialize enum names
as strings
By default, fields are ignored. Use the [JsonInclude] attribute to include fields
The default maximum depth is 64
By default, comments or trailing commas in the JSON throw exceptions. To
allow comments in the JSON, we can set the JsonSerializerOptions
.ReadCommentHandling property to JsonCommentHandling.Skip](https://image.slidesharecdn.com/slot0506-workingwithxmlandjsonserializing-220721084056-59a0c8bc/85/Working-with-XML-and-JSON-Serializing-39-320.jpg)
Working with XML and JSON Serializing
- 1. Working with XML and JSON Serializing
- 2. 2 Overview Serialization in .NET Understanding Serialization Engines in .NET Explain about how serialization works Describe use Serialization Overview XML Serialization Overview JSON (JavaScript Object Notation) Serialization Create demo using XML with WPF application Create demo XML Serialization in .NET application Create demo JSON Serialization in .NET application 7/21/2022 Objectives
- 4. 7/21/2022 4 Understanding Serialization in .NET Serialization is the act of taking an in-memory object or object graph (set of objects that reference one another) and flattening it into a stream of bytes, XML, JSON, or a similar representation that can be stored or transmitted Deserialization works in reverse, taking a data stream and reconstituting it into an in-memory object or object graph There are four serialization engines in .NET : XmlSerializer (XML) JsonSerializer (JSON) The data contract serializer (XML and JSON) The binary serializer (binary)
- 5. 7/21/2022 5 Understanding Serialization Engines XmlSerializer: Serializes and deserializes objects into and from XML documents. The XmlSerializer enables us to control how objects are encoded into XML JsonSerializer: Provides functionality to serialize objects or value types to JSON and to deserialize JSON into objects or value types The Data Contract Serializer: Serializes and deserializes an instance of a type into an XML stream or document using a supplied Data Contract (classes)
- 6. 7/21/2022 6 Understanding Serialization Engines The Binary Serializer: Serialization can be defined as the process of storing the state of an object to a storage medium. During this process, the public and private fields of the object and the name of the class, including the assembly containing the class, are converted to a stream of bytes, which is then written to a data stream. When the object is subsequently deserialized, an exact clone of the original object is created
- 7. 7/21/2022 7 How Serialization Works The object is serialized to a stream that carries the data. The stream may also have information about the object's type, such as its version, culture, and assembly name. From that stream, the object can be stored in a database, a file, or memory
- 8. 7/21/2022 8 Uses for Serialization Serialization allows the developer to save the state of an object and re-create it as needed, providing storage of objects as well as data exchange. Through serialization, a developer can perform actions such as: Sending the object to a remote application by using a web service Passing an object from one domain to another Passing an object through a firewall as a JSON or XML string Maintaining security or user-specific information across applications
- 10. 7/21/2022 10 What is the XML? XML stands for Extensible Markup Language. It is a text-based markup language derived from Standard Generalized Markup Language (SGML) XML tags identify the data and are used to store and organize the data, rather than specifying how to display it like HTML tags, which are used to display the data. There are three important characteristics of XML that make it useful in a variety of systems and solutions: XML is extensible: XML allows us to create our self-descriptive tags, or language, that suits our the application XML carries the data, does not present it: XML allows us to store the data irrespective of how it will be presented XML is a public standard: XML was developed by an organization called the World Wide Web Consortium (W3C) and is available as an open standard
- 11. 7/21/2022 11 What is the XML? An XML document can have only one root element. The following diagram depicts the syntax rules to write different types of markup and text in an XML document
- 12. XmlDataProvider in WPF Application Demonstration
- 13. 7/21/2022 13 1.Create a WPF app named ContactListApp 2.Right-click on the project | Add | New Item, select XML File then rename to Contacts.xml , click Add and write contents as follows: <?xml version="1.0" encoding="utf-8" ?> <ContactList> <Contact Id="001"> <ContactName >Maria Anders</ContactName> <Company>Alfreds Futterkiste</Company> <Phone>030-0074321</Phone> </Contact> <Contact Id="002"> <ContactName >Thomas Hardy</ContactName> <Company>Around & The Horn</Company> <Phone>(171) 555-7788</Phone> </Contact> <Contact Id="003"> <ContactName >Elizabeth Lincoln</ContactName> <Company>Bottom-Dollar & Markets</Company> <Phone>(604) 555-4729</Phone> </Contact> </ContactList>
- 14. 7/21/2022 14 3.Right-click on the project, select Edit Project File and write config information as follows then press Crtl+S to save: <Project Sdk="Microsoft.NET.Sdk"> <PropertyGroup> <OutputType>WinExe</OutputType> <TargetFramework>net5.0-windows</TargetFramework> <UseWPF>true</UseWPF> </PropertyGroup> <ItemGroup> <Content Include="Contacts.xml"> <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory> </Content> </ItemGroup> </Project>
- 15. 7/21/2022 15 4.Write code for MainWindow.xaml as follows: <Window x:Class="ContactListApp.MainWindow" //xmlns:…… Title="Contact List" Height="300" SizeToContent="Width" WindowStartupLocation="CenterScreen"> <Window.Resources> <XmlDataProvider Source="Contacts.xml" XPath="ContactList/Contact" x:Key="ContactList"/> </Window.Resources> <Grid> <ListView Name="lvContacts" Margin="31,14,31,16" ItemsSource="{Binding Source={StaticResource ContactList}}"> <ListView.View> <GridView> <GridViewColumn Header="Id" DisplayMemberBinding="{Binding XPath=@Id}"/> <GridViewColumn Header="Contact Name" Width="100" DisplayMemberBinding="{Binding XPath=ContactName }"/> <GridViewColumn Header="Company" Width="200" DisplayMemberBinding="{Binding XPath=Company}"/> <GridViewColumn Header="Phone" Width="150" DisplayMemberBinding="{Binding XPath=Phone}"/> </GridView> </ListView.View> </ListView> </Grid> </Window>
- 16. 7/21/2022 16 5.Press Crtl+F5 to run project
- 17. 7/21/2022 17 Understanding XmlSerializer The XML serialization engine can produce only XML, and it is less powerful than the binary and data contract serializers in saving and restoring a complex object The XML serialization is the process of converting an object's public properties and fields to a serial format (in this case, XML) for storage or transport. Deserialization re-creates the object in its original state from the XML output The data in our objects is described using programming language constructs like classes, fields, properties, primitive types, arrays, and even embedded XML in the form of XmlElement or XmlAttribute objects
- 18. 7/21/2022 18 Understanding XmlSerializer Method Name Description CreateReader() Returns an object used to read the XML document to be serialized CreateWriter() When overridden in a derived class, returns a writer used to serialize the object Deserialize(Stream) Deserializes the XML document contained by the specified Stream Deserialize(TextReader) Deserializes the XML document contained by the specified TextReader Serialize(Stream, Object) Serializes the specified Object and writes the XML document to a file using the specified Stream Serialize(TextWriter, Object) Serializes the specified Object and writes the XML document to a file using the specified TextWriter The following table describes some of the methods of the XmlSerializer class:
- 19. Serializing as XML Demonstration
- 20. 7/21/2022 20 1. Create a Console app named DemoXmlSerializer 2. Write code for Program.cs as follows then press Ctrl+F5 to run project XmlSerializer Demo-01
- 21. 7/21/2022 21 1. Create a Console app named DemoXmlSerializer02 2. Right-click on the project , select Add | Class named Person.cs then write codes as follows: 3. Write code for Program.cs as follows then press Ctrl+F5 to run project XmlSerializer Demo-02
- 22. 7/21/2022 22
- 23. 7/21/2022 23
- 25. 7/21/2022 25 What is the JSON? JSON stands for JavaScript Object Notation JSON is a lightweight format for storing and transporting data JSON is often used when data is sent from a server to a web page JSON is "self-describing" and easy to understand { "firstName":"John", "lastName":"Doe" } JSON data is written as name/value pairs, just like JavaScript object properties. A name/value pair consists of a field name (in double quotes), followed by a colon, followed by a value:
- 26. 7/21/2022 26 JSON Syntax Rules Data is in name/value pairs Data is separated by commas Curly braces hold objects Square brackets hold arrays { "employees": [ {"firstName":"John", "lastName":"Doe"}, {"firstName":"Anna", "lastName":"Smith"}, {"firstName":"Peter", "lastName":"Jones"} ] }
- 27. 7/21/2022 27 JSON Data Types JSON supports mainly 06 data types: String, Number, Boolean, null, Object, and Array String: JSON strings must be written in double quotes like C-language there are various special characters(Escape Characters) in JSON that you can use in strings such as (backslash), / (forward slash), b (backspace), n (new line), r (carriage return), t (horizontal tab), etc Example: { "name":"Vivek" } { "city":"Delhi/India" } here / is used for Escape Character / (forward slash)
- 28. 7/21/2022 28 JSON Data Types Number: Represented in base 10. The octal and hexadecimal formats are not used Example: { "age": 20 } , { "percentage": 82.44} Boolean: This data type can be either true or false Example: { "result" : true } Null: It is just a define null value Example: { "middlename":null }
- 29. 7/21/2022 29 JSON Data Types Object: It is a set of name or value pairs inserted between {} (curly braces). The keys must be strings and should be unique and multiple key and value pairs are separated by a, (comma) Syntax: { key : value, .......} Example: { “student":{ "name":“David", "age":20, "score": 50.05} }
- 30. 7/21/2022 30 JSON Data Types Array: It is an ordered collection of values and begins with [ (left bracket) and ends with ] (right bracket). The values of array are separated by ,(comma) Syntax: [ value, .......] Example: { "collection" : [ {"id" : 101}, {"id" : 102}, {"id" : 103} ] }
- 31. 7/21/2022 31 Understanding JSON Serialization The JSON (JavaScript Object Notation) serializer is fast and efficient, and was introduced relatively recently to .NET (.NET Core). It also offers good version tolerance and allows the use of custom converters for flexibility JsonSerializer is used by ASP.NET Core 3, removing the dependency on Json.NET, though it is straightforward to opt back in to Json.NET should its features be required JsonSerializer (in the System.Text.Json namespace) is straightforward to use because of the simplicity of the JSON format. The root of a JSON document is either an array or an object. Under that root are properties, which can be an object, array, string, number, "true", "false", or "null" The JSON serializer directly maps class property names to property names in JSON
- 32. 7/21/2022 32 Understanding JSON Serialization Method Name Description Deserialize(String, Type, JsonSerializerOptions) Parses the text representing a single JSON value into an instance of a specified type Deserialize(Utf8JsonReader, Type, JsonSerializerOptions) Reads one JSON value (including objects or arrays) from the provided reader and converts it into an instance of a specified type Deserialize<TValue>(String, JsonSerializerOptions) Parses the text representing a single JSON value into an instance of the type specified by a generic type parameter. Serialize(Object, Type, JsonSerializerOptions) Converts the value of a specified type into a JSON string Serialize(Utf8JsonWriter, Object, Type, JsonSerializerOptions) Writes the JSON representation of the specified type to the provided writer SerializeToUtf8Bytes(Object, Type, JsonSerializerOptions) Converts a value of the specified type into a JSON string, encoded as UTF-8 bytes Serialize<TValue>(TValue, JsonSerializerOptions) Converts the value of a type specified by a generic type parameter into a JSON string The following table describes some of the methods of the JsonSerializer class:
- 33. 7/21/2022 33 Controlling Serialization with Attributes We can control the serialization process with attributes defined in the System.Text.Json.Serialization namespace The following subsections present the most useful attributes: Attribute Name Description JsonIgnoreAttribute Prevents a property from being serialized or deserialized JsonPropertyNameAttribute Specifies the property name that is present in the JSON when serializing and deserializing. This overrides any naming policy specified by JsonNamingPolicy JsonExtensionDataAttribute When placed on a property of type IDictionary<TKey,TValue>, any properties that do not have a matching member are added to that dictionary during deserialization and written during serialization JsonConverterAttribute Converts an object or value to or from JSON JsonIncludeAttribute Indicates that the member should be included for serialization and deserialization JsonNumberHandlingAttribute When placed on a type, property, or field, indicates what JsonNumberHandling settings should be used when serializing or deserializing numbers
- 34. 7/21/2022 34 Controlling Serialization with Attributes Demo //… using System.Text.Json; using System.Text.Json.Serialization;
- 35. 7/21/2022 35 JSON Serialization Options The serializer accepts an optional JsonSerializationOptions parameter, allowing additional control over the serialization and deserialization process The following subsections present the most useful options: Property Name Description WriteIndented Gets or sets a value that defines whether JSON should use pretty printing. By default, JSON is serialized without any extra white space AllowTrailingCommas Get or sets a value that indicates whether an extra comma at the end of a list of JSON values in an object or array is allowed (and ignored) within the JSON payload being deserialized ReadCommentHandling Gets or sets a value that defines how comments are handled during deserialization PropertyNameCaseInsensitive Gets or sets a value that determines whether a property's name uses a case- insensitive comparison during deserialization. The default value is false ReferenceHandler Configures how object references are handled when reading and writing JSON
- 36. 7/21/2022 36 JSON Serialization Options Property Name Description PropertyNamingPolicy Gets or sets a value that specifies the policy used to convert a property's name on an object to another format, such as camel-casing, or null to leave property names unchanged DictionaryKeyPolicy Gets or sets the policy used to convert a IDictionary key's name to another format, such as camel-casing Encoder Gets or sets the encoder to use when escaping strings, or null to use the default encoder IgnoreNullValues ets or sets a value that determines whether null values are ignored during serialization and deserialization. The default value is false. IgnoreReadOnlyProperties Determines whether read-only fields are ignored during serialization. A field is read-only if it is marked with the readonly keyword. The default value is false MaxDepth Gets or sets the maximum depth allowed when serializing or deserializing JSON, with the default value of 0 indicating a maximum depth of 64
- 37. 7/21/2022 37 JSON Serialization Options Demo //… using System.Text.Json; using System.Text.Json.Serialization;
- 38. 7/21/2022 38 Json Serialization Behavior By default, all public properties are serialized. To ignore individual properties, use the [JsonIgnore] attribute The default encoder escapes non-ASCII characters, HTML-sensitive characters within the ASCII-range, and characters that must be escaped according to the RFC 8259 JSON spec By default, JSON is minified. To pretty-print the JSON output, set JsonSerializerOptions.WriteIndented to true By default, casing of JSON names matches the .NET names. To set the name of individual properties, we can use the [JsonPropertyName] attribute By default, fields are ignored (use [JsonInclude] attribute to include fields)
- 39. 7/21/2022 39 Json Deserialization Behavior By default, property name matching is case-sensitive If the JSON contains a value for a read-only property, the value is ignored and no exception is thrown. Non-public constructors are ignored by the serializer Deserialization to immutable objects or read-only properties is supported By default, enums are supported as numbers. We can serialize enum names as strings By default, fields are ignored. Use the [JsonInclude] attribute to include fields The default maximum depth is 64 By default, comments or trailing commas in the JSON throw exceptions. To allow comments in the JSON, we can set the JsonSerializerOptions .ReadCommentHandling property to JsonCommentHandling.Skip
- 40. Serializing as Json Demonstration
- 41. 7/21/2022 41 1.Create a WPF app named ManageProductsApp includes a window named WindowManageProducts.xaml that has controls as follows : ListView Control TextBox Control Label Control Button Control
- 42. 7/21/2022 42 XAML code of WindowManageProducts.xaml: <Window x:Class="ManageProductsApp.WindowManageProducts" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:Demo_JSON_Serialization" mc:Ignorable="d" Title="Manage Products" Height="430" Width="420" Loaded="Window_Loaded" WindowStartupLocation="CenterScreen" ResizeMode="NoResize"> <DockPanel VerticalAlignment="Top" Margin="10"> <Grid> </Grid> </DockPanel> </Window> View details in next slide
- 43. 7/21/2022 43 XAML code of Grid tag <Grid> <Grid.RowDefinitions> <RowDefinition Height="*"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <StackPanel Background="LightBlue" Orientation ="Vertical" HorizontalAlignment="Left" Width="400"> <Label Name="lblInstruction" Foreground="Red" FontWeight="DemiBold" FontSize="20" Content="Product Information"/> <Label Name="lblProductID" Content="ProductID"/> <TextBox Name="txtProductID" HorizontalAlignment="Left" Height="25" Width="300" Text="{Binding Path=ProductID, Mode=OneWay}" DataContext="{Binding ElementName=lvProducts, Path=SelectedItem}" /> <Label Name="lbProductName" Content="Product Name" /> <TextBox Name="txtProductName" HorizontalAlignment="Left" Height="25" Width="300" Text="{Binding Path=ProductName, Mode=OneWay}" DataContext="{Binding ElementName=lvProducts, Path=SelectedItem}" />
- 44. 7/21/2022 44 XAML code of Grid tag (cont.) <StackPanel Orientation="Horizontal" HorizontalAlignment="Left"> <Button x:Name="btnInsert" Margin="10" Width="70" Content="Insert" Click="btnInsert_Click" /> <Button x:Name="btnUpdate" Margin="10" Width="70" Content="Update" Click="btnUpdate_Click"/> <Button x:Name="btnDelete" Margin="10" Width="70" Content="Delete" Click="btnDelete_Click"/> </StackPanel> </StackPanel> <ListView Grid.Row="1" Name="lvProducts" Width="400" > <ListView.View> <GridView> <GridViewColumn Header="Product ID" Width="100" DisplayMemberBinding="{Binding Path=ProductID }"/> <GridViewColumn Header="Product Name" Width="200" DisplayMemberBinding="{Binding Path=ProductName}"/> </GridView> </ListView.View> </ListView> </Grid>
- 45. 7/21/2022 45 2.Right-click on the project | Add | Class, named ManageProducts.cs then write codes as follows:
- 46. 7/21/2022 46
- 47. 7/21/2022 47 3.Write codes in WindowManageProducts.xaml.cs as follows
- 48. 7/21/2022 48
- 49. 7/21/2022 49
- 50. 7/21/2022 50 4. Press Ctrl+F5 to run project and view the output
- 51. Summary Concepts were introduced: Overview Serialization in .NET Understanding Serialization Engines in .NET Explain about how serialization works Describe use Serialization Overview XML Serialization Overview JSON Serialization Create demo using XML with WPF application Create demo XML Serialization in .NET application Create demo JSON Serialization in .NET application 51