Develop Reference

C# appsetttings bind array of objects to class

I have int appsettings.js section like that:
"AccessKeys": {
"user1": {
"pass": ""
},
I created classes in C# to bind this section to these classes:
public class AccessKeys
{
public List Users = new List();
}
public class AccessKeyUserJson
{
public AccessKeyUser AccessKeyUser { get; set; }
}
public class AccessKeyUser
{
public string Pass { get; set; }
}
I bind above classes in Startup.cs:
services.Configure<AppSettingsConfig>(Configuration);
In AppSettingsConfig I have property AccessKeys and this property is binded correctly but Users is empty (0 items)
I changed structure:
"AccessKeys": [
{
"user1": "",
"pass": ""
},
]

Why don't you try something like this:
using (var ms = new System.IO.MemoryStream(Encoding.Unicode.GetBytes(myJSONstring)))
{
System.Runtime.Serialization.Json.DataContractJsonSerializer js = new System.Runtime.Serialization.Json.DataContractJsonSerializer(typeof(myStruct));
myStruct aux = (myStruct)js.ReadObject(ms);
}
This is a single level approach, and sincerely, I've never tried to cast anything in a sub-classing scheme but maybe it worths trying.
As you can see, here, the JSON string is taken by a Memory Stream and then casted into the final struct/class.

How can I parse json to a C# object (Class)?

I have JSON data that I need to parse from C# object.
this is JSON Example.
{
"types":
[
[
"tour_type",
[
["groups",1],
["individual",2]
]
]
]
}
Here are my C# classes that are meant to contain that data:
using System;
using Newtonsoft.Json;
namespace JsonDeserializationTest
{
[JsonProperty("types")]
public class Types
{
[JsonProperty]
public List<Type> Values {get;set;}
}
public class Type
{
[JsonProperty]
public string Key {get;set;}
[JsonProperty]
public List<Dictionary<string, int>> Values { get; set; }
}
}
It's not working now.
How can I fix it?

Use the JsonSerializer (System.Text.Json) object.
Code:
YourClass obj = JsonSerializer.Deserialize<YourClass>(jsonString);

Your json has a list of list of the object... but you are declaring only List of the object.
public class Types
{
[JsonProperty("types")]
public List<List<object>> Values { get; set; }
// ------ UPDATE: This can only be list of list of 'object' ------- \\
}
Also, you are using the JsonProperty on the class, which is not where that normally goes. You want to use that on the property of the class.
UPDATE:
You cannot use List<List<Type>> for the json you are getting, it can only be List<List<object>>. You have to use object because it can either be a string or a List<List<string>>. After you update your Types class, you can successfully deserialize the json above.
var obj = JsonConvert.DeserializeObject<Types>(json);
and based on your json definition, you can access tour_type by using the following code
types.Values.First()[0].ToString()
// output: tour_type
List<List<string>> data = JsonConvert.DeserializeObject<List<List<string>>>(types.Values.First()[1].ToString())
// data[0]
[0]: "groups"
[1]: "1"
// data[1]
[0]: "individual"
[1]: "2"
Since both of the items in the types are objects, you will either have to convert them to string or a list of list of strings or whatever object they actually are.

The JSON payload in the provided example is formatted quite strangely, especially since it contains seemingly unnecessary array nesting. A payload like this usually includes more nested objects (rather than a bunch of nested arrays). Additionally, it has a list of (string, int) pairs, which is semantically very similar to a Dictionary<string, int>, but the payload doesn't lend itself to that. It would be helpful to know where it is coming from (what context) to understand how it might change.
The example JSON brings up a few questions (that you may want to ask yourself):
Can the "types" array contain multiple entries (at its immediate nesting)?
Can the "tour_type" key name appear after the array of string, int pairs? Is it possible for an entry where no such name exists?
What other elements can exist in the arrays within "tour_type"?
Is it guaranteed that the most nested array will contain just a single (string, int) pair?
Similarly, it is hard to understand what the example C# class is trying to encapsulate. Is List<Dictionary<string, int>> necessary?
All that said, here's a solution using the built-in System.Text.Json library, that could work for you. You could write something similar using Newtonsoft.Json, if necessary. The solution assumes:
We can't change the JSON payload (and that the third party API response will always returns something that is structurally similar to the example)
We can only make minimal changes to the C# class object provided in the example
The solution creates and a JsonConverter<T> that uses the low-level Utf8JsonReader to manually parse and create the custom object. This is required since nested "[" are being used to delineate what should be objects rather than "{". The converter is then registered by annotating the class with the attribute. Now, simply call JsonSerializer.Deserialize, passing in the JSON payload.
public class Tours
{
[JsonPropertyName("types")]
public List<UserType> Types { get; set; }
}
// Annotate the type to register the converter to use
[JsonConverter(typeof(CustomUserTypeConverter))]
public class UserType
{
public string Key { get; set; }
public Dictionary<string, int> Values { get; set; }
}
// This will use the low-level reader to build up the UserType
public class CustomUserTypeConverter : JsonConverter<UserType>
{
// Extra structural validation was done for invalid/incomplete JSON
// which might be too strict or incorrect and hence might require adjustments.
public override UserType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
{
var result = new UserType();
if (!reader.Read())
{
throw new JsonException("Incomplete JSON.");
}
if (reader.TokenType != JsonTokenType.EndArray)
{
result.Key = reader.GetString();
ReadAndValidate(ref reader, JsonTokenType.StartArray);
int depthSnapshot = reader.CurrentDepth;
var values = new Dictionary<string, int>();
do
{
reader.Read();
if (reader.TokenType != JsonTokenType.StartArray && reader.TokenType != JsonTokenType.EndArray)
{
throw new JsonException($"Invalid JSON payload. Expected Start or End Array. TokenType: {reader.TokenType}, Depth: {reader.CurrentDepth}.");
}
if (reader.CurrentDepth <= depthSnapshot)
{
break;
}
reader.Read();
if (reader.TokenType != JsonTokenType.EndArray)
{
string key = reader.GetString();
reader.Read();
int value = reader.GetInt32();
values.Add(key, value);
ReadAndValidate(ref reader, JsonTokenType.EndArray);
}
} while (true);
ReadAndValidate(ref reader, JsonTokenType.EndArray);
result.Values = values;
}
return result;
}
private void ReadAndValidate(ref Utf8JsonReader reader, JsonTokenType expectedTokenType)
{
bool readNext = reader.Read();
if (!readNext || reader.TokenType != expectedTokenType)
{
string message = readNext ?
$"Invalid JSON payload. TokenType: {reader.TokenType}, Depth: {reader.CurrentDepth}, Expected: {expectedTokenType}" :
$"Incomplete JSON. Expected: {expectedTokenType}";
throw new JsonException(message);
}
}
// Implement this method if you need to Serialize (i.e. write) the object
// back to JSON
public override void Write(Utf8JsonWriter writer, UserType value, JsonSerializerOptions options)
{
throw new NotImplementedException();
}
}
Here's how you would use the above converter to serialize the JSON string provided in the example, along with how to access the values.
public static Tours ParseJson(string json)
{
Tours tours = JsonSerializer.Deserialize<Tours>(json);
return tours;
}
public static void AccessValues(Tours tours)
{
foreach (UserType data in tours.Types)
{
string typeName = data.Key; // "tour_type"
foreach (KeyValuePair<string, int> pairs in data.Values)
{
string key = pairs.Key; // "groups" or "individual
int value = pairs.Value; // 1 or 2
}
}
}
For what it's worth, Visual Studio suggests the following C# class structure for the example JSON (which is similar to what #Jawad suggested):
public class Rootobject
{
public object[][] types { get; set; }
}
Hope that helps.

I couldn't figure out your JSON so I created an example with verified JSON.
Try this:
JSON:
{
"Items": [
{
"Name": "tour",
"Attributes": [
{
"Name": "groups",
"Value": 1
},
{
"Name": "individual",
"Value": 2
}
]
},
{
"Name": "demo",
"Attributes": [
{
"Name": "this is demo",
"Value": 3
},
{
"Name": "design pattern",
"Value": 99
}
]
}
]
}
Types foo = JsonSerializer.Deserialize<Types>(jsonString);
public class TypeAttribute
{
public string Name { get; set; }
public int Value { get; set; }
}
public class Type
{
private readonly ICollection<TypeAttribute> _attributes;
public Type()
{
_attributes = new Collection<TypeAttribute>();
}
public void AddAttributes(IEnumerable<TypeAttribute> attrs)
{
foreach(TypeAttribute ta in attrs)
{
_attributes.Add(ta);
}
}
public string Name { get; set; }
public IEnumerable<TypeAttribute> Attributes
{
get { return _attributes; }
set
{
foreach(TypeAttribute ta in value)
{
_attributes.Add(ta);
}
}
}
}
public class Types
{
ICollection<Type> _items;
public Types()
{
_items = new Collection<Type>();
}
public void AddItems(IEnumerable<Type> tps)
{
foreach (Type t in tps)
{
_items.Add(t);
}
}
public IEnumerable<Type> Items
{
get { return _items; }
set
{
foreach (Type t in value)
{
_items.Add(t);
}
}
}
}

Xml List Serialization and Node Type Names

Ive come across multiple questions and answers on here but none specific to my situation.
I have a class 'Entity' with multiple classes that extend off of it. I want the serialization to hit the list and understand and use the type of each item for the node name.
Now, I can use what is commented out (define each array item in the main class and define the name of such by using [XmlArrayItem("Subclass1", typeof(subclass1)] but I want to keep all definitions in their subclass and I will be having too many subclasses to define everything in the main entity class...Is there anyway to achieve this?
I have tried using [XmlType(TypeName="...")] for the subclasses and so on but that did not work.
[Serializable]
[XmlInclude(typeof(Subclass1))]
[XmlRoot("Entity")]
public class Entity{
[XmlArray("CausedBy")]
//[XmlArrayItem("Subclass1", typeof(subclass1))]
//[XmlArrayItem("Sublcass2", typeof(Subclass2))]
public List<Entity> CausedBy { get; set; }
}
[Serializable]
[XmlRoot("Subclass1")]
[XmlInclude(typeof(Subclass2))]
public class Subclass1:Entity{
//Code...
}
[Serializable]
[XmlRoot("Subclass2")]
public class Subclass2:Subclass1{
//Code...
}
Serializing the above code after creating an entity and adding a Subclass1 and Subclass2 to the list 'CausedBy' class results in the following:
<Entity>
<CausedBy>
<Entity ... xsi:type="SubClass1" />
<Entity ... xsi:type="SubClass2" />
</CausedBy>
<Entity>
I would like the output to show:
<Entity>
<CausedBy>
<SubClass1 .../>
<SubClass2 .../>
</CausedBy>
<Entity>

Since I totally failed to read the question to begin with, here's a new answer (it's a bit of a tl;dr, so you can always skip to the end and follow the link):
It isn't possible to get the built in serializer class to work because you don't wish to add the attributes that it needs to be able to operate. Your only option is to seralize the class yourself, however, this need not be as tedious as it sounds; I had a similar issue a few years ago with DataGridView in virtual mode and produced a generic virtualizer that could be used to virtualize the data for display; it used a custom attribute:
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
public sealed class showColumnAttribute : System.Attribute
{
///<summary>Optional display format for column</summary>
public string Format;
///<summary>Optional Header string for column<para>Defaults to propety name</para></summary>
public string Title;
///<summary>Optional column edit flag - defaults to false</summary>
public bool ReadOnly;
///<summary>Optional column width</summary>
public int Width;
///<summary>
///Marks public properties that are to be displayed in columns
///</summary>
public showColumnAttribute()
{
Format = String.Empty;
Title = String.Empty;
ReadOnly = false;
Width = 0;
}
}
And a constructor:
///<summary>
///Extracts the properties of the supplied type that are to be displayed
///<para>The type must be a class or an InvalidOperationException will be thrown</para>
///</summary>
public Virtualiser(Type t)
{
if (!t.IsClass)
throw new InvalidOperationException("Supplied type is not a class");
List<VirtualColumnInfo> definedColumns = new List<VirtualColumnInfo>();
PropertyInfo[] ps = t.GetProperties();
MethodInfo mg, ms;
for (int i = 0; i < ps.Length; i++)
{
Object[] attr = ps[i].GetCustomAttributes(true);
if (attr.Length > 0)
{
foreach (var a in attr)
{
showColumnAttribute ca = a as showColumnAttribute;
if (ca != null)
{
mg = ps[i].GetGetMethod();
if (mg != null)
{
ms = ps[i].GetSetMethod();
definedColumns.Add
(
new VirtualColumnInfo
(
ps[i].Name, ca.Width, ca.ReadOnly, ca.Title == String.Empty ? ps[i].Name : ca.Title,
ca.Format, mg, ms
)
);
}
break;
}
}
}
}
if (definedColumns.Count > 0)
columns = definedColumns.ToArray();
}
This extracts the public properties of the class and supplies marked items to the DataGridView as columns together with a header, format, etc.
The effect of all of this (and the rest of the missing code) was that any type could be virtualized in a dataGridView simply by tagging public properties and calling the virtualizer once for a given type:
#region Virtualisation
static readonly Virtualiser Virtual = new Virtualiser(typeof(UserRecord));
[XmlIgnore] // just in case!
public static int ColumnCount { get { return Virtual.ColumnCount; } }
public static VirtualColumnInfo ColumnInfo(int column)
{
return Virtual.ColumnInfo(column);
}
public Object GetItem(int column)
{
return Virtual.GetItem(column, this);
}
/*
** The supplied item should be a string - it is up to this method to supply a valid value to the property
** setter (this is the simplest place to determine what this is and how it can be derived from a string).
*/
public void SetItem(int column, Object item)
{
String v = item as String;
int t = 0;
if (v == null)
return;
switch (Virtual.GetColumnPropertyName(column))
{
case "DisplayNumber":
if (!int.TryParse(v, out t))
t = 0;
item = t;
break;
}
try
{
Virtual.SetItem(column, this, item);
}
catch { }
}
#endregion
The number of columns, their properties and order can be specified automatically by creating a number of public properties derived from the class data:
#region Display columns
[showColumn(ReadOnly = true, Width = 100, Title = "Identification")]
public String DisplayIdent
{
get
{
return ident;
}
set
{
ident = value;
}
}
[showColumn(Width = 70, Title = "Number on Roll")]
public int DisplayNumber
{
get
{
return number;
}
set
{
number = value;
}
}
[showColumn(Width = -100, Title = "Name")]
public string DisplayName
{
get
{
return name == String.Empty ? "??" : name;
}
set
{
name = value;
}
}
#endregion
This would virtualize any class for dataGridView to display and edit data and I used it many times over the years and the extraction of properties to display is exactly what is required for XML serialization, indeed, it has a lot of the same characteristics.
I was going to adapt this method to do the same job for XML serialization but someone has already done it at https://www.codeproject.com/script/Articles/ViewDownloads.aspx?aid=474453, I hope you can make use of this method to solve your problem.

This works for me:
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
Entity entity = new Entity();
entity.CausedBy = new List<Entity>();
entity.CausedBy.Add(new Subclass1());
entity.CausedBy.Add(new Subclass2());
entity.CausedBy.Add(new Subclass2());
entity.CausedBy.Add(new Subclass1());
entity.CausedBy.Add(new Subclass1());
entity.Save(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), "Test.txt"));
}
}
[Serializable]
[XmlRoot("Entity")]
public class Entity
{
[XmlArray("CausedBy")]
[XmlArrayItem("SubClass1", typeof(Subclass1))]
[XmlArrayItem("SubClass2", typeof(Subclass2))]
public List<Entity> CausedBy { get; set; }
}
[Serializable]
[XmlRoot("Subclass1")]
public class Subclass1 : Entity
{
[XmlIgnore]
String t = DateTime.Now.ToShortDateString();
public String SubClass1Item { get { return "Test1 " + t; } set { } }
}
[Serializable]
[XmlRoot("Subclass2")]
public class Subclass2 : Entity
{
[XmlIgnore]
String t = DateTime.Now.ToString();
public String SubClass2Item { get { return "Test2 " + t; } set { } }
}
It produces:
<Entity xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<CausedBy>
<SubClass1>
<SubClass1Item>Test1 20/09/2017</SubClass1Item>
</SubClass1>
<SubClass2>
<SubClass2Item>Test2 20/09/2017 01:06:55</SubClass2Item>
</SubClass2>
<SubClass2>
<SubClass2Item>Test2 20/09/2017 01:06:55</SubClass2Item>
</SubClass2>
<SubClass1>
<SubClass1Item>Test1 20/09/2017</SubClass1Item>
</SubClass1>
<SubClass1>
<SubClass1Item>Test1 20/09/2017</SubClass1Item>
</SubClass1>
</CausedBy>
</Entity>

Serialize Property, but Do Not Deserialize Property in Json.Net

While I've found plenty of approaches to deserializing specific properties while preventing them from serializing, I'm looking for the opposite behavior.
I've found plenty of questions asking the inverse:
Making a property deserialize but not serialize with json.net
Can I instruct Json.NET to deserialize, but not serialize, specific properties?
JSON.Net - Use JsonIgnoreAttribute only on serialization (But not when deserialzing)
How can I serialize a specific property, but prevent it from deserializing back to the POCO? Is there an attribute I can use to decorate the specific property?
Basically I'm looking for an equivalent to the ShouldSerialize* methods for deserialization.
I know I can write a custom converter, but that seems like overkill for this.
Edit:
Here's a little more context. The reason behind this is my class looks like:
public class Address : IAddress
{
/// <summary>
/// Gets or sets the two character country code
/// </summary>
[JsonProperty("countryCode")]
[Required]
public string CountryCode { get; set; }
/// <summary>
/// Gets or sets the country code, and province or state code delimited by a vertical pipe: <c>US|MI</c>
/// </summary>
[JsonProperty("countryProvinceState")]
public string CountryProvinceState
{
get
{
return string.Format("{0}|{1}", this.CountryCode, this.ProvinceState);
}
set
{
if (!string.IsNullOrWhiteSpace(value) && value.Contains("|"))
{
string[] valueParts = value.Split('|');
if (valueParts.Length == 2)
{
this.CountryCode = valueParts[0];
this.ProvinceState = valueParts[1];
}
}
}
}
[JsonProperty("provinceState")]
[Required]
public string ProvinceState { get; set; }
}
I need the CountryProvinceState property for the request, but I don't want it to deserialize back and trigger the setter logic.

Simplest method would be to mark the real property as [JsonIgnore] and create a get-only proxy property:
/// <summary>
/// Gets or sets the country code, and province or state code delimited by a vertical pipe: <c>US|MI</c>
/// </summary>
[JsonIgnore]
public string CountryProvinceState
{
get
{
return string.Format("{0}|{1}", this.CountryCode, this.ProvinceState);
}
set
{
if (!string.IsNullOrWhiteSpace(value) && value.Contains("|"))
{
string[] valueParts = value.Split('|');
if (valueParts.Length == 2)
{
this.CountryCode = valueParts[0];
this.ProvinceState = valueParts[1];
}
}
}
}
[JsonProperty("countryProvinceState")]
string ReadCountryProvinceState
{
get { return CountryProvinceState; }
}
The proxy property can be private if you desire.
Update
If you have to do this for lots of properties in lots of classes, it might be easier to create your own ContractResolver that checks for a custom attribute. If found, the attribute would signal that the property is get-only:
[System.AttributeUsage(System.AttributeTargets.Property, AllowMultiple = false)]
public class GetOnlyJsonPropertyAttribute : Attribute
{
}
public class GetOnlyContractResolver : DefaultContractResolver
{
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
var property = base.CreateProperty(member, memberSerialization);
if (property != null && property.Writable)
{
var attributes = property.AttributeProvider.GetAttributes(typeof(GetOnlyJsonPropertyAttribute), true);
if (attributes != null && attributes.Count > 0)
property.Writable = false;
}
return property;
}
}
Then use it like:
[JsonProperty("countryProvinceState")]
[GetOnlyJsonProperty]
public string CountryProvinceState { get; set; }
And then:
var settings = new JsonSerializerSettings { ContractResolver = new GetOnlyContractResolver() };
var address = JsonConvert.DeserializeObject<Address>(jsonString, settings);

In your question you have a simple string property. But it's a bit more complicated when you have an object. The solution with .Writeable = false will not work, as deserialization will go to properties of an object. Consider the following code:
public class Constants
{
public Address Headquarters { get; set; }
public static Constants Instance = new Constants
{
Headquarters = new Address { Street = "Baker Street" }
};
}
public class Address
{
public string Street { get; set; }
}
public class Data
{
[GetOnlyJsonProperty]
// we want this to be included in the response, but not deserialized back
public Address HqAddress { get { return Constants.Instance.Headquarters; } }
}
// somewhere in your code:
var data = JsonConvert.DeserializeObject<Data>("{'HqAddress':{'Street':'Liverpool Street'}}", settings);
Now JSON will still not try to create a new Addreess object for HqAddress property, as it only has getter. But then (even though .Writeable == false) it goes deeper and deserializes Street property, setting "Liverpool Street" into Constants.Instance.Heqdquarters object, overwriting data in Constants of your application.
Solution is:
In a new version of Newtonsoft.JSON (I tried in v10), there is a new property ShouldDeserialize. So the resolver should be:
public class GetOnlyContractResolver : DefaultContractResolver
{
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
var property = base.CreateProperty(member, memberSerialization);
if (property != null) // Change here (1)
{
var attributes = property.AttributeProvider.GetAttributes(typeof(GetOnlyJsonPropertyAttribute), true);
if (attributes != null && attributes.Count > 0)
property.ShouldDeserialize = (a) => false; // Change here (2)
}
return property;
}
}
(1) I removed the condition for && property.Writeable, so it processes the HqAddress and skips deserialization for a full tree.
(2) ShouldDeserialize is a predicate, called on every object to deserialize. So you can conditionally skip only some properties. But here I made it simple for example.

Display List contents specific field in a ComboBox (C#)

Well, my question is a bit silly, but I've tried lots of different thing without result.
I have a ComboBox in my main form and I want to point its data source to the public readonly List PriceChanges list declared in the Filters class. No problem with that but I want to list the Description field.
I tried to assign the "Description" string to the DisplayMember attribute without success. My ComboBox only lists: "BusinessLogic.PriceChange" for each entry, where BusinessLogic is the name of my Namespace and PriceChange the class.
I appreciate any help.
Regards
That's part of the code of my main form
public mainFrm()
{
InitializeComponent();
prodFilter = new Filters();
cbPriceChanges.DataSource = prodFilter.PriceChanges;
cbPriceChanges.DisplayMember = "Description"
}
That's is part of the code that declares the List object
public enum PriceChangeTypes
{
No_Change,
Increased,
Decreased,
All
}
public class PriceChange
{
public String Description;
public readonly PriceChangeTypes Type;
public delegate bool ComparisonFuntionDelegate(Decimal a);
public readonly ComparisonFuntionDelegate ComparisonFunction;
public PriceChange(String Description, PriceChangeTypes type , ComparisonFuntionDelegate CompFunc)
{
this.Description = Description;
Type = type;
ComparisonFunction = CompFunc;
}
}
public class Filters
{
public readonly List<PriceChange> PriceChanges = null;
public Filters()
{
PriceChanges = new List<PriceChange>();
PriceChanges.Add(new PriceChange("No Change", PriceChangeTypes.No_Change, PriceChange => PriceChange == 0));
PriceChanges.Add(new PriceChange("Increased", PriceChangeTypes.Increased, PriceChange => PriceChange > 0));
PriceChanges.Add(new PriceChange("Decreased", PriceChangeTypes.Decreased, PriceChange => PriceChange < 0));
PriceChanges.Add(new PriceChange("All", PriceChangeTypes.All, a => true));
}
}

Have you tried making "Description" a property? It will change a lot in case the list tries to get the field through reflection (as it most likely does).
public class PriceChange {
public string Description{
get;
set;
}
// ...
}

Try adding this to your class :
public override string ToString()
{
return Description;
}
Currently you're just getting the default value of ToString, which is the object namespace and class