I have a json dataset that varies widely. it can have a field that is either an object or a list. how do I map these into a data model property if when I'm ingesting the data it can be either or. I can have a list of if else statements to check if a property is a list or object but for 10 fields that would grow rather big and make the code ugly.
field:{property1: 3, property2:4}
or
field:{[property1: 3, property2:4], [property1: 5, property2:6]}
if I understand you correctly, you receive data whose format is partially unknown to you.
var input = "{\"field\":{\"property1\": 3, \"property2\":4, \"property3\": 5, \"property4\":6}}";
var obj = JsonConvert.DeserializeObject<JObject>(input);
var res = new MyClass(){Fields = new List<MyField>()};
var field = obj.SelectToken("field") as JObject;
if(field != null)
{
foreach (var item in field.Properties())
{
res.Fields.Add(new MyField()
{
Name = item.Name,
Value = item.Value.Value<int>()
});
}
}
public sealed class MyField
{
public string Name { get; set; }
public object Value { get; set; }
}
public sealed class MyClass
{
public List<MyField> Fields { get; set; }
}
Related
I need to deserialize a JSON string into a type which is not know at compile time. There are several classes that it can be deserialized into. The name of the class is provided as input into the application and based on that I want to instantiate the class (already done this through reflection):
var type = Type.GetType(className);
var myClassInstance = (IParser)Activator.CreateInstance(type);
...and then use its type as the generic type parameter for JsonConvert.DeserializeObject<typeof(myClassInstance).Name>(jsonString) but that doesn't work.
How can I provide the class to DeserializeObject<>() dynamically?
Instead of using an generic method overload like JsonConvert.DeserializeObject<T>(String) and having to resort to reflection as some comments state, you could simply use the non generic counterpart JsonConvert.DeserializeObject(String, Type), which just takes in a Type instance like you already have!
Implementation
Initialization
var class1s = new Class1() {
ID = 1, Name = "Test", Comment = "This Code is Tested!."
};
var class2s = new Class2() {
xVal1 = 1, XVal2 = 5, xval3 = 10
};
var JSON1 = Newtonsoft.Json.JsonConvert.SerializeObject(class1s);
var JSON2 = Newtonsoft.Json.JsonConvert.SerializeObject(class2s);
Calling Functions
var classname1 = typeof(Class1).FullName;
var type1 = Type.GetType(classname1);
var classname2 = typeof(Class2).FullName;
var type2 = Type.GetType(classname2);
var c = LocalConverter(JSON1, type1);
var c2 = LocalConverter(JSON2, type2);
Class Models
public class Class1 {
public int ID {
get;
set;
}
public string Name {
get;
set;
}
public string Comment {
get;
set;
}
}
public class Class2 {
public int xVal1 {
get;
set;
}
public int XVal2 {
get;
set;
}
public int xval3 {
get;
set;
}
}
Required Method
private object LocalConverter(string o, Type xtype) {
return Newtonsoft.Json.JsonConvert.DeserializeObject(o, xtype);
}
I found this answer here at SO, Get nested property values through reflection C#, though when I run it in my case, it also tries to dump/recurse on e.g. a string's property, like Name, and when, it throws an exception.
My classes look like this
public class MyModels
{
public int Id { get; set; }
public DateTime EditDate { get; set; }
public string EditBy { get; set; }
}
public class Person
{
public string Name { get; set; }
}
public class Organization
{
public Person Person { get; set; }
public Organization()
{
Person = new Person();
}
public string Name { get; set; }
}
public class Company : MyModels
{
public Organization Organization { get; set; }
public Company()
{
Organization = new Organization();
}
public string Description { get; set; }
}
And here's the code from the linked answer
var objtree = "";
void DumpObjectTree(object propValue, int level = 0)
{
if (propValue == null)
return;
var childProps = propValue.GetType().GetProperties();
foreach (var prop in childProps)
{
var name = prop.Name;
var value = prop.GetValue(propValue, null);
// add some left padding to make it look like a tree
objtree += ("".PadLeft(level * 4, ' ') + $"{name} = {value}") + Environment.NewLine;
// call again for the child property
DumpObjectTree(value, level + 1);
}
}
DumpObjectTree(itemData);
What I want is to iterate all the properties and check their value.
When I run the above code sample:
it first finds Organization, and recurse
at 1st level it finds Person, and recurse
at 2nd level if finds Name, and recurse
at 3rd level it throws an exception when it tries to GetValue for Name
If I remove my nested classes, and run it:
it first finds Description, and recurse
at 1st level it throws an exception when it tries to GetValue for Description
How do I make it to not try to dump/recurse on properties of type string, datetime, etc., like e.g. Name, Description?
The exception message says: "Parameter count mismatch."
As a note , the expected output/content in the objtree variable is e.g.
Organization = MyNameSpace.Models.Organization
Person = MyNameSpace.Models.Person
Name = TestName
Name = TestCompany
Description = Some info about the company...
Id = 1
EditDate = 31/08/2019
EditBy = user#domain.com
The reason for the exception is that string has a property named Chars. You normally don't see this property, because it's the indexer used when you do something like char c = myString[0];.
This property obviously needs a paramter (the index), and since you don't provide one, an exception is thrown.
To filter the types you don't want to recurse you need to extend the first line in the method. For example
if (propValue == null) return;
if (propValue.GetType().Assembly != Assembly.GetExecutingAssembly())
return;
This will only recurse through types declared in your assembly. If you want special filtering you need to adjust it.
Your current specification ("of type string, datetime etc") is not specific enough to give an exact solution, but I think the idea is clear.
Note that this won't prevent an exception to be raised if you declare an indexer in your own classes. So a better way might be to check for indexers directly:
foreach (var prop in childProps)
{
if (prop.GetIndexParameters().Any()) continue;
Second note: The current code has another flaw: You should keep track of which types you already dumped and abort the recursion when you come across a type the second time. That's possibly the reason for the exception at DateTime. A DateTime has a Date property, which is - hurray - of type DateTime. And so your objtree string grows infinitly until an OutOfMemoryException or StackOverflowException is thrown.
You need to skip recursion when:
Property is a value type
Property is a string
Property value contains reference to the object from the previous recursion level (ie, ParentObject) so that you don't get a stack overflow exception
Edit: Also when property is a collection type. If you want to get creative, you can have your recursor iterate through each object in the collection and then recurse through those
This PropertyInfo recursor seems to do the trick.
[Flags]
public enum PropertyRecursionOverflowProtectionType
{
SkipSameReference,
SkipSameType
}
public class PropertyRecursionBot
{
public object ParentObject { get; set; }
public object CurrentObject { get; set; }
public PropertyInfo PropertyInfo { get; set; }
public Type ParentType { get; set; }
public int Level { get; set; }
}
public static IEnumerable<PropertyRecursionBot> GetAllProperties(object entity,
PropertyRecursionOverflowProtectionType overflowProtectionType = PropertyRecursionOverflowProtectionType.SkipSameReference)
{
var type = entity.GetType();
var bot = new PropertyRecursionBot { CurrentObject = entity };
IEnumerable<PropertyRecursionBot> GetAllProperties(PropertyRecursionBot innerBot, PropertyInfo[] properties)
{
var currentParentObject = innerBot.ParentObject;
var currentObject = innerBot.CurrentObject;
foreach (var pi in properties)
{
innerBot.PropertyInfo = pi;
var obj = pi.GetValue(currentObject);
innerBot.CurrentObject = obj;
//Return the property and value only if it's a value type or string
if (pi.PropertyType == typeof(string) || !pi.PropertyType.IsClass)
{
yield return innerBot;
continue;
}
//This overflow protection check will prevent stack overflow if your object has bidirectional navigation
else if (innerBot.CurrentObject == null ||
(overflowProtectionType.HasFlag(PropertyRecursionOverflowProtectionType.SkipSameReference) && innerBot.CurrentObject == currentParentObject) ||
(overflowProtectionType.HasFlag(PropertyRecursionOverflowProtectionType.SkipSameType) && innerBot.CurrentObject.GetType() == currentParentObject?.GetType()))
{
continue;
}
innerBot.Level++;
innerBot.ParentObject = currentObject;
foreach (var innerPi in GetAllProperties(innerBot, pi.PropertyType.GetProperties()))
{
yield return innerPi;
}
innerBot.Level--;
innerBot.ParentObject = currentParentObject;
innerBot.CurrentObject = obj;
}
}
foreach (var pi in GetAllProperties(bot, type.GetProperties()))
{
yield return pi;
}
}
Use it like this:
public class RecursionTest
{
public string StringValue { get; set; }
public int IntValue { get; set; }
public RecursionTest Test { get; set; }
public RecursionTest ParentTest { get; set; }
}
var rec1 = new RecursionTest
{
IntValue = 20,
StringValue = Guid.NewGuid().ToString()
};
rec1.Test = new RecursionTest
{
IntValue = 30,
StringValue = Guid.NewGuid().ToString(),
ParentTest = rec1
};
rec1.Test.Test = new RecursionTest
{
IntValue = 40,
StringValue = Guid.NewGuid().ToString(),
ParentTest = rec1.Test
};
foreach (var bot in GetAllProperties(rec1, PropertyRecursionOverflowProtectionType.SkipSameReference))
{
Console.WriteLine($"{new string(' ', bot.Level * 2)}{bot.PropertyInfo.Name}: {bot.CurrentObject}");
}
I have the following code which returns results from a database table comprising of an Id field and a Name field, and transfers it to a list of SelectListItems (this populates a dropdown box in my view.)
var locationTypes = await APIHelper.GetAsync<List<LocationType>>(url);
var items = new List<SelectListItem>();
items.AddRange(locationTypes.Select(locationType =>
{
var item = new SelectListItem();
item.Value = locationType.LocationTypeId.ToString();
item.Text = locationType.Name;
return item;
}));
I am repeating this a lot throughout my application, substituting LocationType for various other things. The item.Value always gets the Id property of the data returned (the Id field is always in the format of {TableName}+"Id"), and the item.Text always gets ".Name" property.
How can I make this generic? I am trying to achieve something like this, although it is syntactically incorrect and may be the incorrect approach:
var myGenericObjects = await APIHelper.GetAsync<List<T>>(url)
var items = new List<SelectListItem>();
items.AddRange(myGenericObjects .Select(myGenericObjects =>
{
var item = new SelectListItem();
item.Value = myGenericObject.Field[0].ToString();
item.Text = myGenericObject.Name;
return item;
}));
You can create a custom extension for a generic list object, then, using reflection retrieve the values that you are wanting to map to the SelectListItem.Text and Name fields. Note I am using "nameof" in order to prevent any confusion or magic string representations of the properties to which I am trying to map.
I did define a default value of "Name" to the namePropertyName parameter. Per your description it sounded like, by convention, most of your DTOs have the property "Name" in them. If that's not the case simply remove the default value that is defined.
There are additional checks that could be made to this extension to prevent NullReference and ArgumentExceptions as well, but for simplicity of the example were left out. Example: Ensuring a value is provided in the idPropertyName and namePropertyName parameters and ensuring those property names exist on the provided generic object prior to conversion.
public static class ListExtensions
{
public static List<SelectListItem> ToSelectList<T>(this List<T> list, string idPropertyName, string namePropertyName = "Name")
where T : class, new()
{
List<SelectListItem> selectListItems = new List<SelectListItem>();
list.ForEach(item =>
{
selectListItems.Add(new SelectListItem
{
Text = item.GetType().GetProperty(namePropertyName).GetValue(item).ToString(),
Value = item.GetType().GetProperty(idPropertyName).GetValue(item).ToString()
});
});
return selectListItems;
}
}
Example Use:
var testList = new List<TestDto>
{
new TestDto { Name = "Test0", TestId = 0 },
new TestDto { Name = "Test1", TestId = 1 },
new TestDto { Name = "Test2", TestId = 2 },
new TestDto { Name = "Test3", TestId = 3 },
new TestDto { Name = "Test4", TestId = 4 },
};
var selectList = testList.ToSelectList(nameof(TestDto.TestId), nameof(TestDto.Name));
Here is the TestDto class for reference:
public class TestDto
{
public int TestId { get; set; }
public string Name { get; set; }
}
Some Prep Work
If you can change the table column names, then use a convention. For example, always name the "Value" column "X", and the "Text" column "Y" (give them better names). Then make all the classes for those tables implement an interface similar to this:
public interface ICustomLookup
{
string X { get; set; }
string Y { get; set; }
}
public class SomeClass : ICustomLookup
{
public string X { get; set; }
public string Y { get; set; }
}
Then an extension method like so:
public static class EnumerableExtension
{
public static SelectList ToSelectList(this IEnumerable<ICustomLookup> items)
{
return new SelectList(items.Select(thisItem => new SelectListItem
{
Text = thisItem.X,
Value = thisItem.Y
}));
}
}
Usage
var items = new List<SomeClass>
{
new SomeClass { X = "XOne", Y = "YOne" },
new SomeClass { X = "XTwo", Y = "YTwo" }
};
SelectList selectList = items.ToSelectList();
I have generic object and I need to get item {code, description} from it using LINQ Query
Class
[Serializable]
[XmlRoot("Genders")]
public class Gender
{
[XmlElement("Genders")]
public List<GenderListWrap> GenderListWrap = new List<GenderListWrap>();
}
public class GenderListWrap
{
[XmlAttribute("list")]
public string ListTag { get; set; }
[XmlElement("Item")]
public List<Item> GenderList = new List<Item>();
}
public class Item
{
[XmlElement("CODE")]
public string Code { get; set; }
[XmlElement("DESCRIPTION")]
public string Description { get; set; }
}
here in following screen shot I see my data in GenderObject
* EDIT *
Based on your edits, it appears your issue is related to the datatype you are receiving from your "ObjectToXML" method - this returns something of type Object by the looks of your code, not something of the type you have specified in your question. You could try to cast to the expected type eg. Gender GenderObject = (Gender)SystemCore.XMLPrasing.ObjectToXML(...), which may fail (if the returned type isn't actually Gender). Or you could use the .NET built in XML deserialization, which will be able to return objects of the correct type.
Despite the rather odd data structure you have (whay such effort for a list of genders?), if you want a List<Item>, the following will project just the items into a list:
genders.GenderListWrap.SelectMany(l => l.GenderList).ToList();
(This is assuming you have an instance called genders, constructed something like:
var genders = new Gender
{
GenderListWrap = new List<GenderListWrap>
{
new GenderListWrap
{
GenderList = new List<Item>
{
new Item { Code = "F", Description = "Female" },
new Item { Code = "M", Description = "Male" },
}
},
new GenderListWrap
{
GenderList = new List<Item>
{
new Item { Code = "N", Description = "Neutral" },
}
}
}
};
var genderList = genders.GenderListWrap.SelectMany(l => l.GenderList).ToList();
If, however, you want to get a specific item, you can just use the standard index accessors mentioned in comments, eg. genders.GenderListWrap[0].GenderList[0]
This should work for you, if you cast the object you have to Gender and then do a select on it:
var genderList = ((Gender)GenderObject).GenderListWrap.SelectMany(x => x.GenderList);
This will return a collection of Items on which you will have the {code, description} you are looking for.
I am trying to update a List which is a List of Interfaces to concrete classes.
I add to the List each Market type i am interested in, for this Example these Markets are A and B
I loop over all the markets, (sample provided with 3 markets A B & C, we are only interested in A and B) And determine which is of interest to us.
Once found we pass this to an extraction method too do its work and create an instance of the Correct Market_ class type.
This all works fine, but when i try to update the list with the Updates it does not get reflected in the List.
Code below, any Suggestions?
Thanks
public class Test
{
public Test()
{
TheMarkets MarketsToUpdate = new TheMarkets();
List<SpecificCompanyMarket> lstMarks = new List<SpecificCompanyMarket>();
lstMarks.Add(new SpecificCompanyMarket(1234, "A", "Some HTML DATA HERE"));
lstMarks.Add(new SpecificCompanyMarket(5874, "B", "Some HTML DATA HERE"));
lstMarks.Add(new SpecificCompanyMarket(2224, "C", "Some HTML DATA HERE"));
foreach (var item in lstMarks)
{
if (MarketsToUpdate.IsMarketWeAreInterestedIn(item.MarketName))
{
ITheMarkets MarkToUpdate = ExtractMarketData(item);
var obj = MarketsToUpdate.MarketsWeAreInterestedIn.FirstOrDefault(x => x.MarketName() == "A");
if (obj != null)
{
obj = MarkToUpdate;
}
}
}
//Look At MarketsToUpdate Now and the item has not changed, still original values
//I was expecting to see the new values for the fields in A, not the default 0's
}
public ITheMarkets ExtractMarketData(SpecificCompanyMarket item)
{
ITheMarkets market = null;
if (item.MarketName.ToUpper() == "A")
{
Market_A marketType = new Market_A();
marketType.SomeValue1 = 123;
marketType.SomeValue2 = 158253;
market = marketType;
}
//Other Market extractions here
return market;
}
}
public class SpecificCompanyMarket
{
public int MarketId { get; set; }
public string MarketName { get; set; }
public string MarketDataHTML { get; set; }
public SpecificCompanyMarket(int MID, string MName, string MData)
{
MarketId = MID;
MarketName = MName;
MarketDataHTML = MData;
}
}
public class TheMarkets
{
public List<ITheMarkets> MarketsWeAreInterestedIn = new List<ITheMarkets>();
public TheMarkets()
{
Market_A A = new Market_A();
Market_B B = new Market_B();
MarketsWeAreInterestedIn.Add(A);
MarketsWeAreInterestedIn.Add(B);
}
public bool IsMarketWeAreInterestedIn(string strMarketName)
{
bool blnRetVal = false;
foreach (var item in MarketsWeAreInterestedIn)
{
if (item.MarketName().ToUpper().Trim().Equals(strMarketName.ToUpper().Trim()))
{
blnRetVal = true;
break;
}
}
return blnRetVal;
}
}
public interface ITheMarkets
{
string MarketName();
}
public class Market_A : ITheMarkets
{
public string LabelType { get; private set; }
public double SomeValue1 { get; set; }
public double SomeValue2 { get; set; }
public double SomeValue3 { get; set; }
public Market_A()
{
LabelType = "A";
}
public string MarketName()
{
return LabelType;
}
}
public class Market_B : ITheMarkets
{
public string LabelType { get; private set; }
public List<string> SomeList { get; set; }
public double SomeValue { get; set; }
public Market_B()
{
LabelType = "B";
}
public string MarketName()
{
return LabelType;
}
}
This is a short example to get you going. Loop through your list, find the object you want to update, create a new object of that type and then find the original objects index in the list and overwrite it in place. You are essentially just replacing the object in the list with a new one not mutating the existing one.
foreach (var item in lstMarks)
{
//your code to get an object with data to update
var yourObjectToUpdate = item.GetTheOneYouWant();
//make updates
yourObjectToUpdate.SomeProperty = "New Value";
int index = lstMarks.IndexOf(item);
lstMarks[index] = yourObjectToUpdate;
}
You are extracting an obj from marketWeAreInterestedIn list using LINQ's firstOrDefault extension. This is a new object and not a reference to the obj in that list. Therefore, no updates will be reflected in the object inside that list. Try using 'indexof'
You are not storing "list of interfaces" in your list. List<T> stores an array of pointers to objects that support T interface. Once you enumerate (with Linq in your case) your list, you copy a pointer from list, which is not associated with list itself in any way. It is just a pointer to your instance.
To do what you want, you will have to build new list while enumerating the original one, adding objects to it, according to your needs, so the second list will be based on the first one but with changes applied that you need.
You can also replace specific instance at specific index instead of building new list in your code, but to do this you will need to enumerate your list with for loop and know an index for each item:
list[index] = newvalue;
But there is a third solution to update list item directly by Proxying them. This is an example
class ItemProxy : T { public T Value { get; set; } }
var list = new List<ItemProxy<MyClass>>();
list.Insert(new ItemProxy { Value = new MyClass() });
list.Insert(new ItemProxy { Value = new MyClass() });
list.Insert(new ItemProxy { Value = new MyClass() });
foreach(var item in list)
if(item // ...)
item.Value = new MyClass(); // done, pointer in the list is updated.
Third is the best case for perfomance, but it will be better to use this proxying class for something more than just proxying.