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Simplest method to prove that the contents of two lists (containing objects) are equal

I am having a bit of a frustrating time finding a simple method to compare and prove that the contents of two lists are equal. I have looked at a number of solutions on stackoverflow but I have not been successful. Some of the solutions look like they will require a large amount of work to implement and do something that on the face of it to my mind should be simpler, but perhaps I am too simple to realize that this cannot be done simply :)
I have created a fiddle with some detail that can be viewed here: https://dotnetfiddle.net/cvQr5d
Alternatively please find the full example below, I am having trouble with the object comparison method (variable finalResult) as it's returning false and if the content were being compared I would expect the value to be true:
using System;
using System.Collections.Generic;
using System.Linq;
public class ResponseExample
{
public Guid Id { get; set; } = Guid.Parse("00000000-0000-0000-0000-000000000000");
public int Value { get; set; } = 0;
public string Initials { get; set; } = "J";
public string FirstName { get; set; } = "Joe";
public string Surname { get; set; } = "Blogs";
public string CellPhone { get; set; } = "0923232199";
public bool EmailVerified { get; set; } = false;
public bool CellPhoneVerified { get; set; } = true;
}
public class Program
{
public static void Main()
{
var responseOne = new ResponseExample();
var responseTwo = new ResponseExample();
var responseThree = new ResponseExample();
var responseFour = new ResponseExample();
List<ResponseExample> objectListOne = new List<ResponseExample>();
objectListOne.Add(responseOne);
objectListOne.Add(responseTwo);
List<ResponseExample> objectListTwo = new List<ResponseExample>();
objectListTwo.Add(responseThree);
objectListTwo.Add(responseFour);
bool result = objectListOne.Count == objectListTwo.Count();
Console.WriteLine($"Count: {result}");
bool finalResult = ScrambledEquals<ResponseExample>(objectListOne, objectListTwo);
Console.WriteLine($"Object compare: {finalResult}");
}
//https://stackoverflow.com/a/3670089/3324415
public static bool ScrambledEquals<T>(IEnumerable<T> list1, IEnumerable<T> list2)
{
var cnt = new Dictionary<T,
int>();
foreach (T s in list1)
{
if (cnt.ContainsKey(s))
{
cnt[s]++;
}
else
{
cnt.Add(s, 1);
}
}
foreach (T s in list2)
{
if (cnt.ContainsKey(s))
{
cnt[s]--;
}
else
{
return false;
}
}
return cnt.Values.All(c => c == 0);
}
}

As people in comments have pointed out this will not work as comparing a complex type by default compares whether the reference is the same. Field by field comparison will not work without implementing equality methods (and then you would need to overload GetHashCode and so on). See https://learn.microsoft.com/en-us/dotnet/api/system.object.equals?view=net-5.0
However, if you can use c# 9, which is what you have in the fiddle you can define the type as a record instead of class. Records have built in field by field comparison. See https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/tutorials/records#characteristics-of-records
So public class ResponseExample would become public record ResponseExample and your code works as you expect.

Use Enumerable.All<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>) Method which Determines whether all elements of a sequence satisfy a condition.
Once you have initilized your two List
list1.All(x=>list2.Contains(x))
This works by ensuring that all elements in list2 are containted in list1 otherwise returns false

Your method as is will compare if the 2 lists contain the same objects. So it is returning false as there are 4 different objects. If you create your list like this, using the same objects, it will return true:
List<ResponseExample> objectListOne = new List<ResponseExample>();
objectListOne.Add(responseOne);
objectListOne.Add(responseTwo);
List<ResponseExample> objectListTwo = new List<ResponseExample>();
objectListTwo.Add(responseTwo);
objectListTwo.Add(responseOne);
To get a true value when the contents of the objects are the same you could serialize the objects into a json string like this:
public static bool ScrambledEquals<T>(IEnumerable<T> list1, IEnumerable<T> list2)
{
JavaScriptSerializer json = new JavaScriptSerializer();
var cnt = new Dictionary<string,
int>();
foreach (T _s in list1)
{
string s = json.Serialize(_s);
if (cnt.ContainsKey(s))
{
cnt[s]++;
}
else
{
cnt.Add(s, 1);
}
}
foreach (T _s in list2)
{
string s = json.Serialize(_s);
if (cnt.ContainsKey(s))
{
cnt[s]--;
}
else
{
return false;
}
}
return cnt.Values.All(c => c == 0);
}

If the performance is not a big deal, you can use Newtonsoft.Json. We will be able to compare different types of objects as well as run a deep equals check.
First install the package:
Install-Package Newtonsoft.Json
Here is the code snip:
public static bool DeepEqualsUsingJson<T>(IList<T> l1, IList<T> l2)
{
if (ReferenceEquals(l1, l2))
return true;
if (ReferenceEquals(l2, null))
return false;
if (l1.Count != l2.Count)
return false;
var l1JObject = l1.Select(i => JObject.FromObject(i)).ToList();
var l2JObject = l2.Select(i => JObject.FromObject(i)).ToList();
foreach (var o1 in l1JObject)
{
var index = l2JObject.FindIndex(o2 => JToken.DeepEquals(o1, o2));
if (index == -1)
return false;
l2JObject.RemoveAt(index);
}
return l2JObject.Count == 0;
}

dotnet core Storing objects in RedIs

Using .NET Core, I am trying to save and retrieve a JSON Array of the object from Redis using IDistributedCache. Below is my code for storing and reading from Redis cache:
public void Save(string key, object content, int duration)
{
string s;
if (content is string)
{
s = (string)content;
}
else
{
s = JsonConvert.SerializeObject(content);
}
duration = duration <= 0 ? DefaultCacheDuration : duration;
Cache.Set(key, Encoding.UTF8.GetBytes(s), new DistributedCacheEntryOptions()
{
AbsoluteExpiration = DateTime.Now + TimeSpan.FromSeconds(duration)
});
}
public T Get<T>(string key) where T : class
{
var c = Cache.Get(key);
if (c == null)
{
return null;
}
var str = Encoding.UTF8.GetString(c);
if (typeof(T) == typeof(string))
{
return str as T;
}
return JsonConvert.DeserializeObject<T>(str);
}
the object that I want to store is
public class RuleLoadCollection_Result
{
[Key]
public int RuleId { get; set; }
public string RuleName { get; set; }
}
In my biz logic, am saving the object like this
public IQueryable<RuleLoadCollection_Result> GetRuleLibrary()
{
var result = _dbClient.GetRuleLibrary();
_cache.Save("TestKey", result);
return result;
}
the output here is an Array of Object.
[{"ruleId":1,"ruleName":"a1"}]
What code should I write to return the same array of objects from cache? I tried a few options, most of them gave compile or runtime errors. After the bit of browsing, I tried below, it worked, but it is giving only the first element of the array.
public RuleLoadCollection_Result GetRuleLibraryFromCache()
{
return (_cache.Get<List<RuleLoadCollection_Result>>("TestKey").First());
}
output for this is
{"ruleId":1,"ruleName":"a1"}
which I understand why, but what c# should I write to JSON array back which I saved?
below code gives the runtime error
public IQueryable<RuleLoadCollection_Result> GetRuleLibraryFromCache()
{
return (_cache.Get<IQueryable<RuleLoadCollection_Result>>("TestKey"));
}
the runtime error is:
Cannot create and populate list type System.Linq.IQueryable`1[RuleLoadCollection_Result]. Path '', line 1, position 1.

This worked.
public IQueryable<RuleLoadCollection_Result> GetRuleLibraryFromCache()
{
var result = _cache.Get<IEnumerable<RuleLoadCollection_Result>>("TestKey").AsQueryable();
return result;
}

Creating a Session Helper Class that uses an array object C#

I am using a session helper class to track more than several variable. So far I have 30 that are needed from page to page, not all at once of course. I need to convert some of the values from single to array. The Session helper class I use is as follows. For brevity I have shown only two session variables we use for tracking tab index for two accordions.
using System;
using System.Globalization;
using System.Linq;
using System.Web;
public class SessionHelper
{
//Session variable constants
public const string AccordionTop = "#tabTop";
public const string AccordionBot = "#tabBot";
public static T Read<T>(string variable)
{
object value = HttpContext.Current.Session[variable];
if (value == null)
return default(T);
else
return ((T)value);
}
public static void Write(string variable, object value)
{
HttpContext.Current.Session[variable] = value;
}
public static int TabTop
{
get
{
return Read<int>(AccordionTop);
}
set
{
Write(AccordionTop, value);
}
}
public static int TabBot
{
get
{
return Read<int>(AccordionBot);
}
set
{
Write(AccordionBot, value);
}
}
}
So on each page I can work with variables easily as follows:
To Write:
SessionHelper.TabTop = 1; or SessionHelper.TabBot = 3
To Read:
If (SessionHelper.TabTop……….)
This all works fine. I now want to extend this to array values held in session. The array contains int, string and date time value.
For the array session object I have tried adding:
public class SessionHelper
{
public const string CompInfo = "CompAccInfo";
public static T ReadArray<T>(string variable)
{
object[] result = HttpContext.Current.Session[variable] as object[];
if (result == null)
{
return default(T);
//result = new object[30];
}
else
return ((T)(object)result);
}
public static void WriteArray(string variable, object[] value)
{
HttpContext.Current.Session[variable] = value;
}
public static object[] CompDetails
{
get
{
return ReadArray<object[]>(CompInfo);
}
set
{
WriteArray(CompInfo, value);
}
}
}
But then I get an “Object reference not set to…… error when I try to do this:
public void EGetCompanyInformation(MasterPage myMaster, int entityCode)
{
int prevEntity = 0;Using (sqlconnetiooo
.....
//I get values here this works fine
//Then:
sqlr = cmd.ExecuteReader();
sqlr.Read();
if (sqlr.HasRows)
{
//Calculate accounting period adjustment.
yearEndDiff = 12 - Convert.ToInt32(sqlr.GetDateTime(5).Month);
//Company Code.
SessionHelper.CompDetails[0] = sqlr.GetInt32(0);
//Company Name.
SessionHelper.CompDetails[1] = sqlr.GetString(1);
//Currency Unit.
SessionHelper.CompDetails[2] = sqlr.GetString(2);
//Base Currency Code.
SessionHelper.CompDetails[3] = sqlr.GetString(3);
//Reporting Currency Code.
SessionHelper.CompDetails[4] = sqlr.GetString(4);
//Company Year End.
SessionHelper.CompDetails[5] = yearEndDiff;
//Country Code.
SessionHelper.CompDetails[6] = sqlr.GetString(6);
//Country Name.
SessionHelper.CompDetails[7] = sqlr.GetString(7);
//Base Currency Name.
SessionHelper.CompDetails[8] = sqlr.GetString(8);
//Report Currency Name.
SessionHelper.CompDetails[9] = sqlr.GetString(9);
//ClientID.
SessionHelper.CompDetails[10] = sqlr.GetInt32(10);
Other code here
}
}
It seems any SessionHelper.CompDetails[i] does not work : Error Object reference not set to an instance of an object.

What will happen if ReadArray will return default(T)? It will return null. Than access to any object by index inside the array will cause the exception you face.
It is not quite obvious what your code is intended to do.
SessionHelper.CompDetails[0] = sqlr.GetInt32(0);
What do you want here? CompDetails itself should return an array. But you are trying to rewrite it immediately by some values.
If you want to access the CompDetails and rewrite it's objects than you have to instantiate it by
int n = 10;
SessionHelper.CompDetails = new CompDetails[n];

default(object[]) will always throw null. because the array of object is reference type and default value of any reference type is null. So accessing null value will get you Object reference not set to an instance of object.
You can change your old implementation like below:
public static T Read<T>(string variable, int arraySize=10)
{
object value = HttpContext.Current.Session[variable];
if(typeof(T).IsArray && value == null)
{
//array requires size I personally prefer to have
//differnt read method for array.
return ((T)Activator.CreateInstance(typeof(T),arraySize));
}
if(!typeof(T).IsValueType && value == null)
{
//if it is not value type you can return new instance.
return ((T)Activator.CreateInstance(typeof(T)));
}
else if (value == null)
return default(T);
else
return ((T)value);
}
And access SessionHelper as below:
var sessionarray = SessionHelper.Read<object[]>("myarray",15);
....
// then use that sessionarray here.
....

You have to instantiate the CompDetails array before you start assigning values to it.
if (sqlr.HasRows)
{
//Calculate accounting period adjustment.
yearEndDiff = 12 - Convert.ToInt32(sqlr.GetDateTime(5).Month);
// Instantiate array
SessionHelper.CompDetails = new object[11];
//Company Code.
SessionHelper.CompDetails[0] = sqlr.GetInt32(0);
// etc

Returning a different provider (binding) based on an object (callcontext) with Ninject

I'm trying to return a different provider, depending on a custom context. Given the following
public interface IProvider
{
string WhoAreYou();
}
And two providers
namespace ProviderOne
{
public class Implementation : IProvider
{
public string WhoAreYou()
{
return "Provider One";
}
}
}
namespace ProviderTwo
{
public class Implementation : IProvider
{
public string WhoAreYou()
{
return "Provider Two";
}
}
}
And a context as follows
public class CallContext
{
public string SomeValue{ get; set; }
public int AnotherValue { get; set; }
}
My binding looks like this
CallContext context1 = new CallContext()
{
SomeValue = "one",
AnotherValue = 1
};
Bind<IProvider>().To<ProviderOne.Implementation>().WithMetadata("callcontext", context1);
CallContext context2 = new CallContext()
{
SomeValue = "two",
AnotherValue = 2
};
Bind<IProvider>().To<ProviderOne.Implementation>().WithMetadata("callcontext", context2);
I'm fairly certain it is correct up to here, though it's late, and I'm out of ideas.
My problem is getting to those bindings. I have tried various methods
var test1 = kernel.Get<IProvider>(b => b.Get<CallContext>("callcontext") == context1);
//var test1 = kernel.Get<IProvider>(m => m.Has("callcontext") && m.Get<CallContext>("callcontext").Equals(context1));
//var test1 = kernel.Get<IProvider>(m => m.Get<CallContext>("callcontext").Equals(context1));
//var test1 = kernel.Get<IProvider>().Equals(context1);
But they don't work, at best I get the "No binding" error, at worst I just get errors. I'm sure there must be something easy I am overlooking, or just no aware off.
Thank you

I found the problem, and if anyone runs up against this in the future, the solution above is fine, except you have to explicit override Equals for Ninject to resolve to the object. As follows.
public override bool Equals(object obj)
{
if (obj.GetType() == typeof(CallContext))
{
var context = (CallContext)obj;
if (Country != null)
{
if (Country.ToLower() != context.Country.ToLower())
return false;
}
if (Store != context.Store)
return false;
return true;
}
return false;
}
Then you can resolve it as proposed.
CallContext context1 = new CallContext()
{
SomeValue = "one",
AnotherValue = 1
};
var test1 = kernel.Get<IProvider>(b => b.Get<CallContext>("callcontext").Equals(context1));

How to get current property name via reflection?

I would like to get property name when I'm in it via reflection. Is it possible?
I have code like this:
public CarType Car
{
get { return (Wheel) this["Wheel"];}
set { this["Wheel"] = value; }
}
And because I need more properties like this I would like to do something like this:
public CarType Car
{
get { return (Wheel) this[GetThisPropertyName()];}
set { this[GetThisPropertyName()] = value; }
}

Since properties are really just methods you can do this and clean up the get_ returned:
class Program
{
static void Main(string[] args)
{
Program p = new Program();
var x = p.Something;
Console.ReadLine();
}
public string Something
{
get
{
return MethodBase.GetCurrentMethod().Name;
}
}
}
If you profile the performance you should find MethodBase.GetCurrentMethod() is miles faster than StackFrame. In .NET 1.1 you will also have issues with StackFrame in release mode (from memory I think I found it was 3x faster).
That said I'm sure the performance issue won't cause too much of a problem- though an interesting discussion on StackFrame slowness can be found here.
I guess another option if you were concerned about performance would be to create a Visual Studio Intellisense Code Snippet that creates the property for you and also creates a string that corresponds to the property name.

Slightly confusing example you presented, unless I just don't get it.
From C# 6.0 you can use the nameof operator.
public CarType MyProperty
{
get { return (CarType)this[nameof(MyProperty)]};
set { this[nameof(MyProperty)] = value]};
}
If you have a method that handles your getter/setter anyway, you can use the C# 4.5 CallerMemberName attribute, in this case you don't even need to repeat the name.
public CarType MyProperty
{
get { return Get<CarType>(); }
set { Set(value); }
}
public T Get<T>([CallerMemberName]string name = null)
{
return (T)this[name];
}
public void Set<T>(T value, [CallerMemberName]string name = null)
{
this[name] = value;
}

I'd like to know more about the context in which you need it since it seems to me that you should already know what property you are working with in the property accessor. If you must, though, you could probably use MethodBase.GetCurrentMethod().Name and remove anything after get_/set_.
Update:
Based on your changes, I would say that you should use inheritance rather than reflection. I don't know what data is in your dictionary, but it seems to me that you really want to have different Car classes, say Sedan, Roadster, Buggy, StationWagon, not keep the type in a local variable. Then you would have implementations of methods that do the proper thing for that type of Car. Instead of finding out what kind of car you have, then doing something, you then simply call the appropriate method and the Car object does the right thing based on what type it is.
public interface ICar
{
void Drive( decimal velocity, Orientation orientation );
void Shift( int gear );
...
}
public abstract class Car : ICar
{
public virtual void Drive( decimal velocity, Orientation orientation )
{
...some default implementation...
}
public abstract void Shift( int gear );
...
}
public class AutomaticTransmission : Car
{
public override void Shift( int gear )
{
...some specific implementation...
}
}
public class ManualTransmission : Car
{
public override void Shift( int gear )
{
...some specific implementation...
}
}

Use MethodBase.GetCurrentMethod() instead!
Reflection is used to do work with types that can't be done at compile time. Getting the name of the property accessor you're in can be decided at compile time so you probably shouldn't use reflection for it.
You get use the accessor method's name from the call stack using System.Diagnostics.StackTrace though.
string GetPropertyName()
{
StackTrace callStackTrace = new StackTrace();
StackFrame propertyFrame = callStackTrace.GetFrame(1); // 1: below GetPropertyName frame
string properyAccessorName = propertyFrame.GetMethod().Name;
return properyAccessorName.Replace("get_","").Replace("set_","");
}

FWIW I implemented a system like this:
[CrmAttribute("firstname")]
public string FirstName
{
get { return GetPropValue<string>(MethodBase.GetCurrentMethod().Name); }
set { SetPropValue(MethodBase.GetCurrentMethod().Name, value); }
}
// this is in a base class, skipped that bit for clairty
public T GetPropValue<T>(string propName)
{
propName = propName.Replace("get_", "").Replace("set_", "");
string attributeName = GetCrmAttributeName(propName);
return GetAttributeValue<T>(attributeName);
}
public void SetPropValue(string propName, object value)
{
propName = propName.Replace("get_", "").Replace("set_", "");
string attributeName = GetCrmAttributeName(propName);
SetAttributeValue(attributeName, value);
}
private static Dictionary<string, string> PropToAttributeMap = new Dictionary<string, string>();
private string GetCrmAttributeName(string propertyName)
{
// keyName for our propertyName to (static) CrmAttributeName cache
string keyName = this.GetType().Name + propertyName;
// have we already done this mapping?
if (!PropToAttributeMap.ContainsKey(keyName))
{
Type t = this.GetType();
PropertyInfo info = t.GetProperty(propertyName);
if (info == null)
{
throw new Exception("Cannot find a propety called " + propertyName);
}
object[] attrs = info.GetCustomAttributes(false);
foreach (object o in attrs)
{
CrmAttributeAttribute attr = o as CrmAttributeAttribute ;
if (attr != null)
{
// found it. Save the mapping for next time.
PropToAttributeMap[keyName] = attr.AttributeName;
return attr.AttributeName;
}
}
throw new Exception("Missing MemberOf attribute for " + info.Name + "." + propertyName + ". Could not auto-access value");
}
// return the existing mapping
string result = PropToAttributeMap[keyName];
return result;
}
There's also a custom attribute class called CrmAttributeAttribute.
I'd strongly recommend against using GetStackFrame() as part of your solution, my original version of the solution was originally the much neater:
return GetPropValue<string>();
But it was 600x slower than the version above.

Solution # 1
var a = nameof(SampleMethod); //a == SampleMethod
var b = nameof(SampleVariable); //b == SampleVariable
var c = nameof(SampleProperty); //c == SampleProperty
Solution # 2
MethodBase.GetCurrentMethod().Name; // Name of method in which you call the code
MethodBase.GetCurrentMethod().Name.Replace("set_", "").Replace("get_", ""); // current Property
Solution # 3
from StackTrace:
public static class Props
{
public static string CurrPropName =>
(new StackTrace()).GetFrame(1).GetMethod().Name.Replace("set_", "").Replace("get_", "");
public static string CurrMethodName =>
(new StackTrace()).GetFrame(1).GetMethod().Name;
}
you just need to call Props.CurrPropName or Props.CurrMethodName
Solution # 4
Solution for .NET 4.5+:
public static class Props
{
public static string GetCallerName([System.Runtime.CompilerServices.CallerMemberName] String propertyName = "")
{
return propertyName;
}
}
usage: Props.GetCallerName();

Yes, it is!
string test = "test string";
Type type = test.GetType();
PropertyInfo[] propInfos = type.GetProperties();
for (int i = 0; i < propInfos.Length; i++)
{
PropertyInfo pi = (PropertyInfo)propInfos.GetValue(i);
string propName = pi.Name;
}

Try using System.Diagnostics.StackTrace to reflect on the call stack. The property should be somewhere in the call stack (probably at the top if you're calling it directly from the property's code).