Related
The goal of this code is to iterate through multiple nested classes, and multiple any integer by 2. Provided simple example, however, example will be more complicated in future.
How do I change a Object to its underlying class? When I iterate through this function, it reads the type for OuterProduct correctly, but fails for InnerProduct reading as type System.RuntimeType, giving an error below
How can I resolve this code to multiply all nested integers by 2?
An unhandled exception of type 'System.StackOverflowException' occurred in Unknown Module.
class Program
{
static void Main(string[] args)
{
var test = new OuterProduct();
test.AmountSold = 5;
test.ProductName = "BookOuter";
test.InnerProduct = new InnerProduct();
test.InnerProduct.ProductNameInner = "BookInner";
test.InnerProduct.AmountSoldInner = 7;
ReadPropertiesTest.ReadPropertiesRecursive(test);
}
}
public class OuterProduct
{
public string ProductName { get; set; }
public int AmountSold { get; set; }
public InnerProduct InnerProduct { get; set; }
}
public class InnerProduct
{
public string ProductNameInner { get; set; }
public int AmountSoldInner { get; set; }
}
public static class ReadPropertiesTest
{
public static void ReadPropertiesRecursive(object test)
{
var type = test.GetType();
foreach (PropertyInfo property in type.GetProperties())
{
if (property.PropertyType == typeof(int) || property.PropertyType == typeof(int?))
{
property.SetValue(test, (int)(property.GetValue(test)) * 2);
}
if (property.PropertyType.IsClass && !(property.PropertyType == typeof(string)))
{
ReadPropertiesRecursive(property.PropertyType);
}
}
}
}
Resources:
C#: How to get all public (both get and set) string properties of a type
How to iterate through nested properties of an object
System.RuntimeType is the implementation of the class that represents typeof(X) or something.GetType(). When you pass PropertyType to your function you are not passing the property value, but it's type.
You will need to pass the next object in the hierarchy into the recursive function by using GetValue.
Note though that this is dangerous and error prone. For example, if you have a List<> property you obviously cannot increase its Count (it is readonly!). You should check to make sure that the property can be written to using the CanWrite property.
You also need to check for null objects. On top of that we need to handle int differently from int? (otherwise casting null to int will throw). The latter we can clean up a bit with c#7 pattern matching:
public static void ReadPropertiesRecursive(object test)
{
if (test is null) // base case
return;
var type = test.GetType();
foreach (PropertyInfo property in type.GetProperties())
{
// check if we can even read the property
if(!property.CanRead)
continue;
// use pattern matching on the value
// nulls will be ignored
// we *could* cache GetValue but then it means we will invoke it for uninteresting types/properties
// it's also why I don't call GetValue until we've inspected PropertyType
if (property.CanWrite &&
(property.PropertyType == typeof(int) || property.PropertyType == typeof(int?)) &&
property.GetValue(test) is int i)
{
property.SetValue(test, i * 2);
}
else if (property.PropertyType.IsClass && property.PropertyType != typeof(string))
{
ReadPropertiesRecursive(property.GetValue(test));
}
}
}
An alternative version that omits some of the checks against PropertyType can also be used. It's a bit cleaner looking but it could potentially perform the GetValue reflection in cases where we don't need/want it (like on a double or a struct):
public static void ReadPropertiesRecursive(object test)
{
if (test is null) // base case
return;
var type = test.GetType();
foreach (PropertyInfo property in type.GetProperties())
{
// check if we can even read the property
if(!property.CanRead)
continue;
// possibly unnecessary if not int or class
var val = property.GetValue(test);
if (property.CanWrite && val is int i)
{
property.SetValue(test, i * 2);
}
else if (property.PropertyType.IsClass && property.PropertyType != typeof(string))
{
ReadPropertiesRecursive(val);
}
}
}
Note that you may want to have a whitelist or blacklist of types. Recursing into a Type object for example isn't going to get you much.
Alternative would be to go with more object-oriented approach. Make it responsibility of every class which need to be "updated".
For every type with properties which need to be updated introduce a method to do it.
public class OuterProduct
{
public string ProductName { get; set; }
public int AmountSold { get; set; }
public InnerProduct InnerProduct { get; set; }
public void Update()
{
AmountSold *= 2;
InnerProduct.Update();
}
}
public class InnerProduct
{
public string ProductNameInner { get; set; }
public int AmountSoldInner { get; set; }
public void Update()
{
AmountSoldInner *= 2;
}
}
// Usage is simple
var test = new OuterProduct
{
AmountSold = 5,
ProductName = "BookOuter",
InnerProduct = new InnerProduct
{
ProductNameInner = "BookInner",
AmountSoldInner = 7
}
};
test.Update();
// test.AmountSold == 10 is true
// test.InnerProduct.AmountSoldInner == 14 is true
This approach will simplify code maintenance. For example adding/removing properties or worse case scenario adding some other logic to Update method will be isolated in one class.
In your recursive call you are passing the type, not the actual property value:
if (property.PropertyType.IsClass && !(property.PropertyType == typeof(string)))
{
ReadPropertiesRecursive(property.PropertyType);
}
should be:
if (property.PropertyType.IsClass && !(property.PropertyType == typeof(string)))
{
ReadPropertiesRecursive(property.GetValue(test));
}
I have two complex objects like Object1 and Object2. They have around 5 levels of child objects.
I need the fastest method to say if they are same or not.
How could this be done in C# 4.0?
Implement IEquatable<T> (typically in conjunction with overriding the inherited Object.Equals and Object.GetHashCode methods) on all your custom types. In the case of composite types, invoke the contained types’ Equals method within the containing types. For contained collections, use the SequenceEqual extension method, which internally calls IEquatable<T>.Equals or Object.Equals on each element. This approach will obviously require you to extend your types’ definitions, but its results are faster than any generic solutions involving serialization.
Edit: Here is a contrived example with three levels of nesting.
For value types, you can typically just call their Equals method. Even if the fields or properties were never explicitly assigned, they would still have a default value.
For reference types, you should first call ReferenceEquals, which checks for reference equality – this would serve as an efficiency boost when you happen to be referencing the same object. It would also handle cases where both references are null. If that check fails, confirm that your instance's field or property is not null (to avoid NullReferenceException) and call its Equals method. Since our members are properly typed, the IEquatable<T>.Equals method gets called directly, bypassing the overridden Object.Equals method (whose execution would be marginally slower due to the type cast).
When you override Object.Equals, you’re also expected to override Object.GetHashCode; I didn’t do so below for the sake of conciseness.
public class Person : IEquatable<Person>
{
public int Age { get; set; }
public string FirstName { get; set; }
public Address Address { get; set; }
public override bool Equals(object obj)
{
return this.Equals(obj as Person);
}
public bool Equals(Person other)
{
if (other == null)
return false;
return this.Age.Equals(other.Age) &&
(
object.ReferenceEquals(this.FirstName, other.FirstName) ||
this.FirstName != null &&
this.FirstName.Equals(other.FirstName)
) &&
(
object.ReferenceEquals(this.Address, other.Address) ||
this.Address != null &&
this.Address.Equals(other.Address)
);
}
}
public class Address : IEquatable<Address>
{
public int HouseNo { get; set; }
public string Street { get; set; }
public City City { get; set; }
public override bool Equals(object obj)
{
return this.Equals(obj as Address);
}
public bool Equals(Address other)
{
if (other == null)
return false;
return this.HouseNo.Equals(other.HouseNo) &&
(
object.ReferenceEquals(this.Street, other.Street) ||
this.Street != null &&
this.Street.Equals(other.Street)
) &&
(
object.ReferenceEquals(this.City, other.City) ||
this.City != null &&
this.City.Equals(other.City)
);
}
}
public class City : IEquatable<City>
{
public string Name { get; set; }
public override bool Equals(object obj)
{
return this.Equals(obj as City);
}
public bool Equals(City other)
{
if (other == null)
return false;
return
object.ReferenceEquals(this.Name, other.Name) ||
this.Name != null &&
this.Name.Equals(other.Name);
}
}
Update: This answer was written several years ago. Since then, I've started to lean away from implementing IEquality<T> for mutable types for such scenarios. There are two notions of equality: identity and equivalence. At a memory representation level, these are popularly distinguished as “reference equality” and “value equality” (see Equality Comparisons). However, the same distinction can also apply at a domain level. Suppose that your Person class has a PersonId property, unique per distinct real-world person. Should two objects with the same PersonId but different Age values be considered equal or different? The answer above assumes that one is after equivalence. However, there are many usages of the IEquality<T> interface, such as collections, that assume that such implementations provide for identity. For example, if you're populating a HashSet<T>, you would typically expect a TryGetValue(T,T) call to return existing elements that share merely the identity of your argument, not necessarily equivalent elements whose contents are completely the same. This notion is enforced by the notes on GetHashCode:
In general, for mutable reference types, you should override GetHashCode() only if:
You can compute the hash code from fields that are not mutable; or
You can ensure that the hash code of a mutable object does not change while the object is contained in a collection that relies on its hash code.
Serialize both objects and compare the resulting strings
You can use extension method, recursion to resolve this problem:
public static bool DeepCompare(this object obj, object another)
{
if (ReferenceEquals(obj, another)) return true;
if ((obj == null) || (another == null)) return false;
//Compare two object's class, return false if they are difference
if (obj.GetType() != another.GetType()) return false;
var result = true;
//Get all properties of obj
//And compare each other
foreach (var property in obj.GetType().GetProperties())
{
var objValue = property.GetValue(obj);
var anotherValue = property.GetValue(another);
if (!objValue.Equals(anotherValue)) result = false;
}
return result;
}
public static bool CompareEx(this object obj, object another)
{
if (ReferenceEquals(obj, another)) return true;
if ((obj == null) || (another == null)) return false;
if (obj.GetType() != another.GetType()) return false;
//properties: int, double, DateTime, etc, not class
if (!obj.GetType().IsClass) return obj.Equals(another);
var result = true;
foreach (var property in obj.GetType().GetProperties())
{
var objValue = property.GetValue(obj);
var anotherValue = property.GetValue(another);
//Recursion
if (!objValue.DeepCompare(anotherValue)) result = false;
}
return result;
}
or compare by using Json (if object is very complex)
You can use Newtonsoft.Json:
public static bool JsonCompare(this object obj, object another)
{
if (ReferenceEquals(obj, another)) return true;
if ((obj == null) || (another == null)) return false;
if (obj.GetType() != another.GetType()) return false;
var objJson = JsonConvert.SerializeObject(obj);
var anotherJson = JsonConvert.SerializeObject(another);
return objJson == anotherJson;
}
If you don't want to implement IEquatable, you can always use Reflection to compare all the properties:
- if they're value type, just compare them
-if they are reference type, call the function recursively to compare its "inner" properties.
I'm not thinking about performace, but about simplicity. It depends, however on the exact design of your objects. It could get complicated depending on your objects shape (for example if there are cyclic dependencies between properties). There are, however, several solutions out there that you can use, like this one:
Compare .NET objects
Another option is to serialize the object as text, for example using JSON.NET, and comparing the serialization result. (JSON.NET can handle Cyclic dependencies between properties).
I don't know if by fastest you mean the fastest way to implement it or a code that runs fast. You should not optimize before knowing if you need to. Premature optimization is the root of all evil
Serialize both objects and compare the resulting strings by #JoelFan
So to do this, create a static class like so and use Extensions to extend ALL objects (so you can pass anytype of object, collection, etc into the method)
using System;
using System.IO;
using System.Runtime.Serialization.Json;
using System.Text;
public static class MySerializer
{
public static string Serialize(this object obj)
{
var serializer = new DataContractJsonSerializer(obj.GetType());
using (var ms = new MemoryStream())
{
serializer.WriteObject(ms, obj);
return Encoding.Default.GetString(ms.ToArray());
}
}
}
Once you reference this static class in any other file, you can do this:
Person p = new Person { Firstname = "Jason", LastName = "Argonauts" };
Person p2 = new Person { Firstname = "Jason", LastName = "Argonaut" };
//assuming you have already created a class person!
string personString = p.Serialize();
string person2String = p2.Serialize();
Now you can simply use .Equals to compare them.
I use this for checking if objects are in collections too. It works really well.
If you have a requirement where you want the class which is immutable. I mean that none of the properties can be modified once it's been created. In that case, C# 9 have a feature which is called a record.
You can easily compare records by values and types is they are equal.
public record Person
{
public string LastName { get; }
public string FirstName { get; }
public Person(string first, string last) => (FirstName, LastName) = (first, last);
}
var person1 = new Person("Bill", "Wagner");
var person2 = new Person("Bill", "Wagner");
Console.WriteLine(person1 == person2); // true
You can now use json.net. Just go on Nuget and install it.
And you can do something like this:
public bool Equals(SamplesItem sampleToCompare)
{
string myself = JsonConvert.SerializeObject(this);
string other = JsonConvert.SerializeObject(sampleToCompare);
return myself == other;
}
You could perhaps make a extension method for object if you wanted to get fancier. Please note this only compares the public properties. And if you wanted to ignore a public property when you do the comparison you could use the [JsonIgnore] attribute.
Serialize both objects, then calculate Hash Code, then compare.
I'll assume you are not referring to literally the same objects
Object1 == Object2
You might be thinking about doing a memory comparison between the two
memcmp(Object1, Object2, sizeof(Object.GetType())
But that's not even real code in c# :). Because all of your data is probably created on the heap, the memory is not contiguous and you can't just compare the equality of two objects in an agnostic manner. You're going to have to compare each value, one at a time, in a custom way.
Consider adding the IEquatable<T> interface to your class, and define a custom Equals method for your type. Then, in that method, manual test each value. Add IEquatable<T> again on enclosed types if you can and repeat the process.
class Foo : IEquatable<Foo>
{
public bool Equals(Foo other)
{
/* check all the values */
return false;
}
}
Based off a few answers already given here I decided to mostly back JoelFan's answer. I love extension methods and these have been working great for me when none of the other solutions would using them to compare my complex classes.
Extension Methods
using System.IO;
using System.Xml.Serialization;
static class ObjectHelpers
{
public static string SerializeObject<T>(this T toSerialize)
{
XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType());
using (StringWriter textWriter = new StringWriter())
{
xmlSerializer.Serialize(textWriter, toSerialize);
return textWriter.ToString();
}
}
public static bool EqualTo(this object obj, object toCompare)
{
if (obj.SerializeObject() == toCompare.SerializeObject())
return true;
else
return false;
}
public static bool IsBlank<T>(this T obj) where T: new()
{
T blank = new T();
T newObj = ((T)obj);
if (newObj.SerializeObject() == blank.SerializeObject())
return true;
else
return false;
}
}
Usage Examples
if (record.IsBlank())
throw new Exception("Record found is blank.");
if (record.EqualTo(new record()))
throw new Exception("Record found is blank.");
I would say that:
Object1.Equals(Object2)
would be what you're looking for. That's if you're looking to see if the objects are the same, which is what you seem to be asking.
If you want to check to see if all the child objects are the same, run them through a loop with the Equals() method.
I found this below function for comparing objects.
static bool Compare<T>(T Object1, T object2)
{
//Get the type of the object
Type type = typeof(T);
//return false if any of the object is false
if (object.Equals(Object1, default(T)) || object.Equals(object2, default(T)))
return false;
//Loop through each properties inside class and get values for the property from both the objects and compare
foreach (System.Reflection.PropertyInfo property in type.GetProperties())
{
if (property.Name != "ExtensionData")
{
string Object1Value = string.Empty;
string Object2Value = string.Empty;
if (type.GetProperty(property.Name).GetValue(Object1, null) != null)
Object1Value = type.GetProperty(property.Name).GetValue(Object1, null).ToString();
if (type.GetProperty(property.Name).GetValue(object2, null) != null)
Object2Value = type.GetProperty(property.Name).GetValue(object2, null).ToString();
if (Object1Value.Trim() != Object2Value.Trim())
{
return false;
}
}
}
return true;
}
I am using it and it is working fine for me.
Thanks to the example of Jonathan. I expanded it for all cases (arrays, lists, dictionaries, primitive types).
This is a comparison without serialization and does not require the implementation of any interfaces for compared objects.
/// <summary>Returns description of difference or empty value if equal</summary>
public static string Compare(object obj1, object obj2, string path = "")
{
string path1 = string.IsNullOrEmpty(path) ? "" : path + ": ";
if (obj1 == null && obj2 != null)
return path1 + "null != not null";
else if (obj2 == null && obj1 != null)
return path1 + "not null != null";
else if (obj1 == null && obj2 == null)
return null;
if (!obj1.GetType().Equals(obj2.GetType()))
return "different types: " + obj1.GetType() + " and " + obj2.GetType();
Type type = obj1.GetType();
if (path == "")
path = type.Name;
if (type.IsPrimitive || typeof(string).Equals(type))
{
if (!obj1.Equals(obj2))
return path1 + "'" + obj1 + "' != '" + obj2 + "'";
return null;
}
if (type.IsArray)
{
Array first = obj1 as Array;
Array second = obj2 as Array;
if (first.Length != second.Length)
return path1 + "array size differs (" + first.Length + " vs " + second.Length + ")";
var en = first.GetEnumerator();
int i = 0;
while (en.MoveNext())
{
string res = Compare(en.Current, second.GetValue(i), path);
if (res != null)
return res + " (Index " + i + ")";
i++;
}
}
else if (typeof(System.Collections.IEnumerable).IsAssignableFrom(type))
{
System.Collections.IEnumerable first = obj1 as System.Collections.IEnumerable;
System.Collections.IEnumerable second = obj2 as System.Collections.IEnumerable;
var en = first.GetEnumerator();
var en2 = second.GetEnumerator();
int i = 0;
while (en.MoveNext())
{
if (!en2.MoveNext())
return path + ": enumerable size differs";
string res = Compare(en.Current, en2.Current, path);
if (res != null)
return res + " (Index " + i + ")";
i++;
}
}
else
{
foreach (PropertyInfo pi in type.GetProperties(BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public))
{
try
{
var val = pi.GetValue(obj1);
var tval = pi.GetValue(obj2);
if (path.EndsWith("." + pi.Name))
return null;
var pathNew = (path.Length == 0 ? "" : path + ".") + pi.Name;
string res = Compare(val, tval, pathNew);
if (res != null)
return res;
}
catch (TargetParameterCountException)
{
//index property
}
}
foreach (FieldInfo fi in type.GetFields(BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public))
{
var val = fi.GetValue(obj1);
var tval = fi.GetValue(obj2);
if (path.EndsWith("." + fi.Name))
return null;
var pathNew = (path.Length == 0 ? "" : path + ".") + fi.Name;
string res = Compare(val, tval, pathNew);
if (res != null)
return res;
}
}
return null;
}
For easy copying of the code created repository
public class GetObjectsComparison
{
public object FirstObject, SecondObject;
public BindingFlags BindingFlagsConditions= BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
}
public struct SetObjectsComparison
{
public FieldInfo SecondObjectFieldInfo;
public dynamic FirstObjectFieldInfoValue, SecondObjectFieldInfoValue;
public bool ErrorFound;
public GetObjectsComparison GetObjectsComparison;
}
private static bool ObjectsComparison(GetObjectsComparison GetObjectsComparison)
{
GetObjectsComparison FunctionGet = GetObjectsComparison;
SetObjectsComparison FunctionSet = new SetObjectsComparison();
if (FunctionSet.ErrorFound==false)
foreach (FieldInfo FirstObjectFieldInfo in FunctionGet.FirstObject.GetType().GetFields(FunctionGet.BindingFlagsConditions))
{
FunctionSet.SecondObjectFieldInfo =
FunctionGet.SecondObject.GetType().GetField(FirstObjectFieldInfo.Name, FunctionGet.BindingFlagsConditions);
FunctionSet.FirstObjectFieldInfoValue = FirstObjectFieldInfo.GetValue(FunctionGet.FirstObject);
FunctionSet.SecondObjectFieldInfoValue = FunctionSet.SecondObjectFieldInfo.GetValue(FunctionGet.SecondObject);
if (FirstObjectFieldInfo.FieldType.IsNested)
{
FunctionSet.GetObjectsComparison =
new GetObjectsComparison()
{
FirstObject = FunctionSet.FirstObjectFieldInfoValue
,
SecondObject = FunctionSet.SecondObjectFieldInfoValue
};
if (!ObjectsComparison(FunctionSet.GetObjectsComparison))
{
FunctionSet.ErrorFound = true;
break;
}
}
else if (FunctionSet.FirstObjectFieldInfoValue != FunctionSet.SecondObjectFieldInfoValue)
{
FunctionSet.ErrorFound = true;
break;
}
}
return !FunctionSet.ErrorFound;
}
Generic Extension Method
public static class GenericExtensions
{
public static bool DeepCompare<T>(this T objA, T objB)
{
if (typeof(T).IsValueType)
return objA.Equals(objB);
if (ReferenceEquals(objA, objB))
return true;
if ((objA == null) || (objB == null))
return false;
if (typeof(T) is IEnumerable)
{
var enumerableA = (IEnumerable<T>) objA;
var enumerableB = (IEnumerable<T>) objB;
if (enumerableA.Count() != enumerableB.Count())
return false;
using (var enumeratorA = enumerableA.GetEnumerator())
using (var enumeratorB = enumerableB.GetEnumerator())
{
while (true)
{
bool moveNextA = enumeratorA.MoveNext();
bool moveNextB = enumeratorB.MoveNext();
if (!moveNextA || !moveNextB)
break;
var currentA = enumeratorA.Current;
var currentB = enumeratorB.Current;
if (!currentA.DeepCompare<T>(currentB))
return false;
}
return true;
}
}
foreach (var property in objA.GetType().GetProperties())
{
var valueA = property.GetValue(objA);
var valueB = property.GetValue(objB);
if (!valueA.DeepCompare(valueB))
return false;
}
return true;
}
}
One way to do this would be to override Equals() on each type involved. For example, your top level object would override Equals() to call the Equals() method of all 5 child objects. Those objects should all override Equals() as well, assuming they are custom objects, and so on until the entire hierarchy could be compared by just performing an equality check on the top level objects.
Use IEquatable<T> Interface which has a method Equals.
To return each property updated:
public IEnumerable<string> GetPropsUpdated(T oldModel, T newModel)
{
var diff = new List<string>();
foreach (var prop in oldModel.GetType().GetProperties())
{
var oldValue = prop.GetValue(oldModel);
var newValue = prop.GetValue(newModel);
if (oldValue == null && newValue == null)
continue;
if (oldValue == null && newValue != null
|| oldValue != null && newValue == null)
{
diff.Add(prop.Name);
continue;
}
var oldPropHashed = oldValue.GetHashCode();
var newPropHashed = newValue.GetHashCode();
if (!oldPropHashed.Equals(newPropHashed))
diff.Add(prop.Name);
}
return diff;
}
I'm working on a project and I need to be able to do the following:
Say, We have Aa class that is configuration class:
public class Aa
{
public Bb BbName { set; get; }
public string Dd { set; get; }
}
public class Bb
{
public string bb { set; get; }
public string cc { set; get; }
}
I want to fetch variables from environment in order to assign them to the respective properties. Here is what I mean: as a simulation of Environment.GetEnvironmentVariable, let's use Dictionary<string, string>.
Setup will look like this:
var dic = new Dictionary<string, string>();
dic.Add("Dd", "236.154");
dic.Add("BbName.bb", "value_for_Bb.bb"); // as you can see, I'm using nested object's full
dic.Add("BbName.cc", "value_for_Bb.cc"); // path, in order to be able to identify it
Then I wrote a method, which looks like this:
private static void ReadPropertiesRecursive<T>(T obj, Type type, List<string> prefixes)
{
foreach (PropertyInfo property in type.GetProperties())
{
if (property.PropertyType.GetTypeInfo().IsClass && property.PropertyType != typeof(string))
{
prefixes.Add(property.Name);
ReadPropertiesRecursive(obj, property.PropertyType, prefixes);
prefixes.Remove(property.Name);
}
else
{
var propertyFullName = prefixes != null && prefixes.Count > 0 ? $"{prefixes.Aggregate((i, j) => i + "." + j)}.{property.Name}" : property.Name;
property.SetValue(obj, dic[propertyFullName]);
Console.WriteLine(propertyFullName); // just for debugging
}
}
}
So, using recursion, I'm able to reach all nested objects of the given Type and the only thing that is left is assigning corresponding values to them. I'm trying to do that on property.SetValue(obj, dic[propertyFullName]);, but it throws an error, and it makes sense: obj is a "root" object, not the one that I want to assign values to, directly. So, I probably need to pass here not obj, but rather an instance of property, which is obj's property. Is that correct? Will that work? If yes, how should I do that?
That did the trick:
private static void ReadPropertiesRecursive<Tt>(Tt obj, Type type, List<string> prefixes)
{
foreach (PropertyInfo property in type.GetProperties())
{
if (property.PropertyType.GetTypeInfo().IsClass && property.PropertyType != typeof(string))
{
prefixes.Add(property.Name);
var val = property.GetValue(obj);
if (val == null)
val = Activator.CreateInstance(property.PropertyType);
property.SetValue(obj, val);
ReadPropertiesRecursive(val, property.PropertyType, prefixes);
prefixes.Remove(property.Name);
}
else
{
var propertyFullName = prefixes != null && prefixes.Count > 0 ? $"{prefixes.Aggregate((i, j) => i + "." + j)}.{property.Name}" : property.Name;
property.SetValue(obj, dic[propertyFullName]);
Console.WriteLine(propertyFullName);
}
}
}
I have a method to update some customer information
public UpdateCustomerInformationResponse UpdateCustomerInformation(UpdateCustomerInformationRequest request)
{
var customer = new Customer
{
FirstName = request.Customer
LastName = request.LastName,
MiddleInitial = request.MiddleInitial,
CustomerEmail = request.CustomerEmail,
UnitNumber = request.UnitNumber,
}
Another object
var fieldRequired = new FieldRequired{
FieldName = "CustomerEmail ",
IsRequired = 1
}
I want to compare 2 objects so that I can find out if FieldName "CustomerEmail"
is present in Customer object.
Its so simple buddy. I found a simple solution using the reflection and extnetion method just follow as below
Create a static class with the name "CompareTwoObjects" and add the code to it.
public static object CompareEquals(this T objectFromCompare, T objectToCompare)//Generic method
{
if (objectFromCompare == null && objectToCompare == null)
return true;
else if (objectFromCompare == null && objectToCompare != null)
return false;
else if (objectFromCompare != null && objectToCompare == null)
return false;
//Gets all the properties of the class
PropertyInfo[] props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
foreach (PropertyInfo prop in props)
{
object dataFromCompare = objectFromCompare.GetType().GetProperty(prop.Name).GetValue(objectFromCompare, null);
object dataToCompare = objectToCompare.GetType().GetProperty(prop.Name).GetValue(objectToCompare, null);
Type type = objectFromCompare.GetType().GetProperty(prop.Name).GetValue(objectToCompare, null).GetType();
if (prop.PropertyType.IsClass && !prop.PropertyType.FullName.Contains("System.String"))
{
dynamic convertedFromValue = Convert.ChangeType(dataFromCompare, type);
dynamic convertedToValue = Convert.ChangeType(dataToCompare, type);
object result = CompareTwoObjects.CompareEquals(convertedFromValue, convertedToValue);
bool compareResult = (bool)result;
if (!compareResult)
return false;
}
else if (!dataFromCompare.Equals(dataToCompare))
return false;
}
return true;
}
This will give the result of two objects are having same values or not.
Usage:-
Object1.CompareEquals(Object2);
If the class object is complex also this will work. If you found any issues please post back
Your question is a little vague. Is this what you are looking for?
if (fieldRequired.FieldName == "CustomerEmail" && fieldRequired.IsRequired == 1)
{
CustomerEmail = request.CustomerEmail;
}
You can implement the interface IEqualtable, then design the method Equals with the data members that you want to compare. You can see an example of this implementation below:
class Customer: IEquatable<Customer>
{
public string FirstName { get; set; }
public string LastName { get; set; }
...
public bool Equals(Person other)
{
return ((FirstName == other.FirstName) &&
(LastName == other.LastName));
}
}
I have two complex objects like Object1 and Object2. They have around 5 levels of child objects.
I need the fastest method to say if they are same or not.
How could this be done in C# 4.0?
Implement IEquatable<T> (typically in conjunction with overriding the inherited Object.Equals and Object.GetHashCode methods) on all your custom types. In the case of composite types, invoke the contained types’ Equals method within the containing types. For contained collections, use the SequenceEqual extension method, which internally calls IEquatable<T>.Equals or Object.Equals on each element. This approach will obviously require you to extend your types’ definitions, but its results are faster than any generic solutions involving serialization.
Edit: Here is a contrived example with three levels of nesting.
For value types, you can typically just call their Equals method. Even if the fields or properties were never explicitly assigned, they would still have a default value.
For reference types, you should first call ReferenceEquals, which checks for reference equality – this would serve as an efficiency boost when you happen to be referencing the same object. It would also handle cases where both references are null. If that check fails, confirm that your instance's field or property is not null (to avoid NullReferenceException) and call its Equals method. Since our members are properly typed, the IEquatable<T>.Equals method gets called directly, bypassing the overridden Object.Equals method (whose execution would be marginally slower due to the type cast).
When you override Object.Equals, you’re also expected to override Object.GetHashCode; I didn’t do so below for the sake of conciseness.
public class Person : IEquatable<Person>
{
public int Age { get; set; }
public string FirstName { get; set; }
public Address Address { get; set; }
public override bool Equals(object obj)
{
return this.Equals(obj as Person);
}
public bool Equals(Person other)
{
if (other == null)
return false;
return this.Age.Equals(other.Age) &&
(
object.ReferenceEquals(this.FirstName, other.FirstName) ||
this.FirstName != null &&
this.FirstName.Equals(other.FirstName)
) &&
(
object.ReferenceEquals(this.Address, other.Address) ||
this.Address != null &&
this.Address.Equals(other.Address)
);
}
}
public class Address : IEquatable<Address>
{
public int HouseNo { get; set; }
public string Street { get; set; }
public City City { get; set; }
public override bool Equals(object obj)
{
return this.Equals(obj as Address);
}
public bool Equals(Address other)
{
if (other == null)
return false;
return this.HouseNo.Equals(other.HouseNo) &&
(
object.ReferenceEquals(this.Street, other.Street) ||
this.Street != null &&
this.Street.Equals(other.Street)
) &&
(
object.ReferenceEquals(this.City, other.City) ||
this.City != null &&
this.City.Equals(other.City)
);
}
}
public class City : IEquatable<City>
{
public string Name { get; set; }
public override bool Equals(object obj)
{
return this.Equals(obj as City);
}
public bool Equals(City other)
{
if (other == null)
return false;
return
object.ReferenceEquals(this.Name, other.Name) ||
this.Name != null &&
this.Name.Equals(other.Name);
}
}
Update: This answer was written several years ago. Since then, I've started to lean away from implementing IEquality<T> for mutable types for such scenarios. There are two notions of equality: identity and equivalence. At a memory representation level, these are popularly distinguished as “reference equality” and “value equality” (see Equality Comparisons). However, the same distinction can also apply at a domain level. Suppose that your Person class has a PersonId property, unique per distinct real-world person. Should two objects with the same PersonId but different Age values be considered equal or different? The answer above assumes that one is after equivalence. However, there are many usages of the IEquality<T> interface, such as collections, that assume that such implementations provide for identity. For example, if you're populating a HashSet<T>, you would typically expect a TryGetValue(T,T) call to return existing elements that share merely the identity of your argument, not necessarily equivalent elements whose contents are completely the same. This notion is enforced by the notes on GetHashCode:
In general, for mutable reference types, you should override GetHashCode() only if:
You can compute the hash code from fields that are not mutable; or
You can ensure that the hash code of a mutable object does not change while the object is contained in a collection that relies on its hash code.
Serialize both objects and compare the resulting strings
You can use extension method, recursion to resolve this problem:
public static bool DeepCompare(this object obj, object another)
{
if (ReferenceEquals(obj, another)) return true;
if ((obj == null) || (another == null)) return false;
//Compare two object's class, return false if they are difference
if (obj.GetType() != another.GetType()) return false;
var result = true;
//Get all properties of obj
//And compare each other
foreach (var property in obj.GetType().GetProperties())
{
var objValue = property.GetValue(obj);
var anotherValue = property.GetValue(another);
if (!objValue.Equals(anotherValue)) result = false;
}
return result;
}
public static bool CompareEx(this object obj, object another)
{
if (ReferenceEquals(obj, another)) return true;
if ((obj == null) || (another == null)) return false;
if (obj.GetType() != another.GetType()) return false;
//properties: int, double, DateTime, etc, not class
if (!obj.GetType().IsClass) return obj.Equals(another);
var result = true;
foreach (var property in obj.GetType().GetProperties())
{
var objValue = property.GetValue(obj);
var anotherValue = property.GetValue(another);
//Recursion
if (!objValue.DeepCompare(anotherValue)) result = false;
}
return result;
}
or compare by using Json (if object is very complex)
You can use Newtonsoft.Json:
public static bool JsonCompare(this object obj, object another)
{
if (ReferenceEquals(obj, another)) return true;
if ((obj == null) || (another == null)) return false;
if (obj.GetType() != another.GetType()) return false;
var objJson = JsonConvert.SerializeObject(obj);
var anotherJson = JsonConvert.SerializeObject(another);
return objJson == anotherJson;
}
If you don't want to implement IEquatable, you can always use Reflection to compare all the properties:
- if they're value type, just compare them
-if they are reference type, call the function recursively to compare its "inner" properties.
I'm not thinking about performace, but about simplicity. It depends, however on the exact design of your objects. It could get complicated depending on your objects shape (for example if there are cyclic dependencies between properties). There are, however, several solutions out there that you can use, like this one:
Compare .NET objects
Another option is to serialize the object as text, for example using JSON.NET, and comparing the serialization result. (JSON.NET can handle Cyclic dependencies between properties).
I don't know if by fastest you mean the fastest way to implement it or a code that runs fast. You should not optimize before knowing if you need to. Premature optimization is the root of all evil
Serialize both objects and compare the resulting strings by #JoelFan
So to do this, create a static class like so and use Extensions to extend ALL objects (so you can pass anytype of object, collection, etc into the method)
using System;
using System.IO;
using System.Runtime.Serialization.Json;
using System.Text;
public static class MySerializer
{
public static string Serialize(this object obj)
{
var serializer = new DataContractJsonSerializer(obj.GetType());
using (var ms = new MemoryStream())
{
serializer.WriteObject(ms, obj);
return Encoding.Default.GetString(ms.ToArray());
}
}
}
Once you reference this static class in any other file, you can do this:
Person p = new Person { Firstname = "Jason", LastName = "Argonauts" };
Person p2 = new Person { Firstname = "Jason", LastName = "Argonaut" };
//assuming you have already created a class person!
string personString = p.Serialize();
string person2String = p2.Serialize();
Now you can simply use .Equals to compare them.
I use this for checking if objects are in collections too. It works really well.
If you have a requirement where you want the class which is immutable. I mean that none of the properties can be modified once it's been created. In that case, C# 9 have a feature which is called a record.
You can easily compare records by values and types is they are equal.
public record Person
{
public string LastName { get; }
public string FirstName { get; }
public Person(string first, string last) => (FirstName, LastName) = (first, last);
}
var person1 = new Person("Bill", "Wagner");
var person2 = new Person("Bill", "Wagner");
Console.WriteLine(person1 == person2); // true
You can now use json.net. Just go on Nuget and install it.
And you can do something like this:
public bool Equals(SamplesItem sampleToCompare)
{
string myself = JsonConvert.SerializeObject(this);
string other = JsonConvert.SerializeObject(sampleToCompare);
return myself == other;
}
You could perhaps make a extension method for object if you wanted to get fancier. Please note this only compares the public properties. And if you wanted to ignore a public property when you do the comparison you could use the [JsonIgnore] attribute.
Serialize both objects, then calculate Hash Code, then compare.
I'll assume you are not referring to literally the same objects
Object1 == Object2
You might be thinking about doing a memory comparison between the two
memcmp(Object1, Object2, sizeof(Object.GetType())
But that's not even real code in c# :). Because all of your data is probably created on the heap, the memory is not contiguous and you can't just compare the equality of two objects in an agnostic manner. You're going to have to compare each value, one at a time, in a custom way.
Consider adding the IEquatable<T> interface to your class, and define a custom Equals method for your type. Then, in that method, manual test each value. Add IEquatable<T> again on enclosed types if you can and repeat the process.
class Foo : IEquatable<Foo>
{
public bool Equals(Foo other)
{
/* check all the values */
return false;
}
}
Based off a few answers already given here I decided to mostly back JoelFan's answer. I love extension methods and these have been working great for me when none of the other solutions would using them to compare my complex classes.
Extension Methods
using System.IO;
using System.Xml.Serialization;
static class ObjectHelpers
{
public static string SerializeObject<T>(this T toSerialize)
{
XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType());
using (StringWriter textWriter = new StringWriter())
{
xmlSerializer.Serialize(textWriter, toSerialize);
return textWriter.ToString();
}
}
public static bool EqualTo(this object obj, object toCompare)
{
if (obj.SerializeObject() == toCompare.SerializeObject())
return true;
else
return false;
}
public static bool IsBlank<T>(this T obj) where T: new()
{
T blank = new T();
T newObj = ((T)obj);
if (newObj.SerializeObject() == blank.SerializeObject())
return true;
else
return false;
}
}
Usage Examples
if (record.IsBlank())
throw new Exception("Record found is blank.");
if (record.EqualTo(new record()))
throw new Exception("Record found is blank.");
I would say that:
Object1.Equals(Object2)
would be what you're looking for. That's if you're looking to see if the objects are the same, which is what you seem to be asking.
If you want to check to see if all the child objects are the same, run them through a loop with the Equals() method.
I found this below function for comparing objects.
static bool Compare<T>(T Object1, T object2)
{
//Get the type of the object
Type type = typeof(T);
//return false if any of the object is false
if (object.Equals(Object1, default(T)) || object.Equals(object2, default(T)))
return false;
//Loop through each properties inside class and get values for the property from both the objects and compare
foreach (System.Reflection.PropertyInfo property in type.GetProperties())
{
if (property.Name != "ExtensionData")
{
string Object1Value = string.Empty;
string Object2Value = string.Empty;
if (type.GetProperty(property.Name).GetValue(Object1, null) != null)
Object1Value = type.GetProperty(property.Name).GetValue(Object1, null).ToString();
if (type.GetProperty(property.Name).GetValue(object2, null) != null)
Object2Value = type.GetProperty(property.Name).GetValue(object2, null).ToString();
if (Object1Value.Trim() != Object2Value.Trim())
{
return false;
}
}
}
return true;
}
I am using it and it is working fine for me.
Thanks to the example of Jonathan. I expanded it for all cases (arrays, lists, dictionaries, primitive types).
This is a comparison without serialization and does not require the implementation of any interfaces for compared objects.
/// <summary>Returns description of difference or empty value if equal</summary>
public static string Compare(object obj1, object obj2, string path = "")
{
string path1 = string.IsNullOrEmpty(path) ? "" : path + ": ";
if (obj1 == null && obj2 != null)
return path1 + "null != not null";
else if (obj2 == null && obj1 != null)
return path1 + "not null != null";
else if (obj1 == null && obj2 == null)
return null;
if (!obj1.GetType().Equals(obj2.GetType()))
return "different types: " + obj1.GetType() + " and " + obj2.GetType();
Type type = obj1.GetType();
if (path == "")
path = type.Name;
if (type.IsPrimitive || typeof(string).Equals(type))
{
if (!obj1.Equals(obj2))
return path1 + "'" + obj1 + "' != '" + obj2 + "'";
return null;
}
if (type.IsArray)
{
Array first = obj1 as Array;
Array second = obj2 as Array;
if (first.Length != second.Length)
return path1 + "array size differs (" + first.Length + " vs " + second.Length + ")";
var en = first.GetEnumerator();
int i = 0;
while (en.MoveNext())
{
string res = Compare(en.Current, second.GetValue(i), path);
if (res != null)
return res + " (Index " + i + ")";
i++;
}
}
else if (typeof(System.Collections.IEnumerable).IsAssignableFrom(type))
{
System.Collections.IEnumerable first = obj1 as System.Collections.IEnumerable;
System.Collections.IEnumerable second = obj2 as System.Collections.IEnumerable;
var en = first.GetEnumerator();
var en2 = second.GetEnumerator();
int i = 0;
while (en.MoveNext())
{
if (!en2.MoveNext())
return path + ": enumerable size differs";
string res = Compare(en.Current, en2.Current, path);
if (res != null)
return res + " (Index " + i + ")";
i++;
}
}
else
{
foreach (PropertyInfo pi in type.GetProperties(BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public))
{
try
{
var val = pi.GetValue(obj1);
var tval = pi.GetValue(obj2);
if (path.EndsWith("." + pi.Name))
return null;
var pathNew = (path.Length == 0 ? "" : path + ".") + pi.Name;
string res = Compare(val, tval, pathNew);
if (res != null)
return res;
}
catch (TargetParameterCountException)
{
//index property
}
}
foreach (FieldInfo fi in type.GetFields(BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public))
{
var val = fi.GetValue(obj1);
var tval = fi.GetValue(obj2);
if (path.EndsWith("." + fi.Name))
return null;
var pathNew = (path.Length == 0 ? "" : path + ".") + fi.Name;
string res = Compare(val, tval, pathNew);
if (res != null)
return res;
}
}
return null;
}
For easy copying of the code created repository
public class GetObjectsComparison
{
public object FirstObject, SecondObject;
public BindingFlags BindingFlagsConditions= BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
}
public struct SetObjectsComparison
{
public FieldInfo SecondObjectFieldInfo;
public dynamic FirstObjectFieldInfoValue, SecondObjectFieldInfoValue;
public bool ErrorFound;
public GetObjectsComparison GetObjectsComparison;
}
private static bool ObjectsComparison(GetObjectsComparison GetObjectsComparison)
{
GetObjectsComparison FunctionGet = GetObjectsComparison;
SetObjectsComparison FunctionSet = new SetObjectsComparison();
if (FunctionSet.ErrorFound==false)
foreach (FieldInfo FirstObjectFieldInfo in FunctionGet.FirstObject.GetType().GetFields(FunctionGet.BindingFlagsConditions))
{
FunctionSet.SecondObjectFieldInfo =
FunctionGet.SecondObject.GetType().GetField(FirstObjectFieldInfo.Name, FunctionGet.BindingFlagsConditions);
FunctionSet.FirstObjectFieldInfoValue = FirstObjectFieldInfo.GetValue(FunctionGet.FirstObject);
FunctionSet.SecondObjectFieldInfoValue = FunctionSet.SecondObjectFieldInfo.GetValue(FunctionGet.SecondObject);
if (FirstObjectFieldInfo.FieldType.IsNested)
{
FunctionSet.GetObjectsComparison =
new GetObjectsComparison()
{
FirstObject = FunctionSet.FirstObjectFieldInfoValue
,
SecondObject = FunctionSet.SecondObjectFieldInfoValue
};
if (!ObjectsComparison(FunctionSet.GetObjectsComparison))
{
FunctionSet.ErrorFound = true;
break;
}
}
else if (FunctionSet.FirstObjectFieldInfoValue != FunctionSet.SecondObjectFieldInfoValue)
{
FunctionSet.ErrorFound = true;
break;
}
}
return !FunctionSet.ErrorFound;
}
Generic Extension Method
public static class GenericExtensions
{
public static bool DeepCompare<T>(this T objA, T objB)
{
if (typeof(T).IsValueType)
return objA.Equals(objB);
if (ReferenceEquals(objA, objB))
return true;
if ((objA == null) || (objB == null))
return false;
if (typeof(T) is IEnumerable)
{
var enumerableA = (IEnumerable<T>) objA;
var enumerableB = (IEnumerable<T>) objB;
if (enumerableA.Count() != enumerableB.Count())
return false;
using (var enumeratorA = enumerableA.GetEnumerator())
using (var enumeratorB = enumerableB.GetEnumerator())
{
while (true)
{
bool moveNextA = enumeratorA.MoveNext();
bool moveNextB = enumeratorB.MoveNext();
if (!moveNextA || !moveNextB)
break;
var currentA = enumeratorA.Current;
var currentB = enumeratorB.Current;
if (!currentA.DeepCompare<T>(currentB))
return false;
}
return true;
}
}
foreach (var property in objA.GetType().GetProperties())
{
var valueA = property.GetValue(objA);
var valueB = property.GetValue(objB);
if (!valueA.DeepCompare(valueB))
return false;
}
return true;
}
}
One way to do this would be to override Equals() on each type involved. For example, your top level object would override Equals() to call the Equals() method of all 5 child objects. Those objects should all override Equals() as well, assuming they are custom objects, and so on until the entire hierarchy could be compared by just performing an equality check on the top level objects.
Use IEquatable<T> Interface which has a method Equals.
To return each property updated:
public IEnumerable<string> GetPropsUpdated(T oldModel, T newModel)
{
var diff = new List<string>();
foreach (var prop in oldModel.GetType().GetProperties())
{
var oldValue = prop.GetValue(oldModel);
var newValue = prop.GetValue(newModel);
if (oldValue == null && newValue == null)
continue;
if (oldValue == null && newValue != null
|| oldValue != null && newValue == null)
{
diff.Add(prop.Name);
continue;
}
var oldPropHashed = oldValue.GetHashCode();
var newPropHashed = newValue.GetHashCode();
if (!oldPropHashed.Equals(newPropHashed))
diff.Add(prop.Name);
}
return diff;
}