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generic type conversion in C#

Is there any way the following code can be improved. I'm aware of the non nullable reference in C# 8.0 and was thinking either that or any other way they code below could be made more robust and better in general.
This method is called for converting xml data before insertion in a database Through entity framework core. Any way these tools can be used to improve this code is welcomed.
public object Convert(string value, Type toType)
{
try
{
if (toType == typeof(short))
{
return short.Parse(value);
}
if (toType == typeof(short?))
{
if (string.IsNullOrEmpty(value))
{
return null;
}
return short.Parse(value);
}
if (toType == typeof(int))
{
return int.Parse(value);
}
if (toType == typeof(int?))
{
if (string.IsNullOrEmpty(value))
{
return null;
}
return int.Parse(value);
}
if (toType == typeof(decimal))
{
return decimal.Parse(value);
}
if (toType == typeof(decimal?))
{
if (string.IsNullOrEmpty(value))
{
return null;
}
return decimal.Parse(value);
}
if (toType == typeof(DateTime))
{
return DateTime.Parse(value);
}
if (toType == typeof(DateTime?))
{
if (string.IsNullOrEmpty(value))
{
return null;
}
return DateTime.Parse(value);
}
throw new NotSupportedException($"No conversion defined for type:'{toType}'");
}
catch (System.FormatException excp)
{
throw new ConversionException($"Value:'{value}' could not be converted to:'{toType.Name}'", excp);
}
}
Many thanks in advance

The only thing I can offer is to improve robustness by using .TryParse() for the parsing instead of .Parse()
class Program
{
static void Main(string[] args)
{
var i = Parse<int>("100");
var x = Parse<double>("3.1417");
var s = Parse<string>("John");
var d = Parse<Decimal>("1234.56");
var f = Parse<DateTime>("4/1/2044");
var q = Parse<byte>("4A");
Decimal? p = Parse<decimal>("Not Decimal");
}
public static dynamic Parse<T>(string text)
{
var toType = typeof(T);
if (toType == typeof(int))
{
if (int.TryParse(text, out int x))
{
return x;
}
}
else if (toType == typeof(short))
{
if (short.TryParse(text, out short x))
{
return x;
}
}
else if (toType == typeof(double))
{
if (double.TryParse(text, out double x))
{
return x;
}
}
else if (toType == typeof(decimal))
{
if (decimal.TryParse(text, out decimal x))
{
return x;
}
}
else if (toType == typeof(DateTime))
{
if (DateTime.TryParse(text, out DateTime x))
{
return x;
}
}
else if (toType == typeof(byte))
{
if (byte.TryParse(text, System.Globalization.NumberStyles.HexNumber, null, out byte x))
{
return x;
}
}
else if (toType == typeof(string))
{
return text;
}
return null;
}
}

IMO the main improvement here would be to remove all boxing. Which means using generics throughout. Now, there's a complication there: with generics, it is hard to change types without with boxing (to convince the compiler you know what you're doing), or using meta-programming. So: I'd lean towards the latter. Something like:
public static T Convert<T>(string input)
=> TypeCache<T>.Convert(input);
private static TypeCache<T> {
public static readonly Func<string, T> Convert
= CreateConverter<T>();
}
private static Func<string, T> CreateConverter<T>()
{...}
The magic all happens in that last method. The problem is: it isn't trivial. The simplest approach should be to use reflection to discover a suitable parse method, then manually construct an Expression<Func<string, T>> by linking appropriate Expression nodes to repreresent the operation, then call Compile() to get a delegate. Another approach is to go straight to DynamicMethod and ILGenerator. Both are advanced topics.

This is the code I wrote and used in my company's project really well.
You can try to use this:
/// <summary>
/// Method : Simply Universal Type Converter
/// Requirement : C# 7.0+
/// Created by : Byungho Park(Tapegawui) in South Korea.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="val">Original value</param>
/// <param name="rfrom">(Optional)Character(s) want to replace from</param>
/// <param name="rto">(Optional)Character(s) will be replace to</param>
/// <returns></returns>
public static T Cast<T>(dynamic val, string rfrom = "", string rto = "") where T : IConvertible
{
try
{
// Convert null to empty else 0
if (val is null || val.Equals(DBNull.Value))
{
if (typeof(T) == typeof(string) || typeof(T) == typeof(DateTime))
{
val = string.Empty;
}
else if (typeof(T) == typeof(bool))
{
val = false;
}
else
{
val = 0;
}
}
else
{
// Replace string given parameter from a to b
if (typeof(T) == typeof(string) && rfrom == "" & rto.Length > 0)
{
if (val.ToString().Length == 0)
{
val = rto;
}
}
else if (typeof(T) == typeof(string) && rto.Length > 0)
{
val = (string)val.ToString().Replace(rfrom, rto);
}
}
// Convert type on this block finally
return (T)Convert.ChangeType(val, typeof(T));
}
catch (Exception)
{
return default(T);
}
}
And usage examples:
using System;
int vint = 10;
int vint2 = vint;
string vstr = "1000000";
string vdcm = "123456789123456789";
for (int i = 1; i <= vint; i++)
{
vint2 += i;
}
Console.WriteLine($"Adding int with loop : {vint2} from {vint}\n");
string tint = Cast<string>(vint);
for (int i = 1; i <= vint; i++)
{
tint += i;
}
Console.WriteLine($"Adding string with loop : {tint} from {vint}\n");
long tlong = Cast<long>(vstr);
tlong *= tlong;
Console.WriteLine($"Multiply long : {tlong} from {vstr}\n");
double tdbl = Cast<double>(vdcm);
for (int i = 1; i <= vint; i++)
{
tdbl *= i;
}
Console.WriteLine($"Multiply double with loop : {tdbl} from {vdcm}\n");
decimal tdcm = Cast<decimal>(vdcm);
for (int i = 1; i <= vint; i++)
{
tdcm *= i;
}
Console.WriteLine($"Multiply decimal with loop : {tdcm} from {vdcm}\n");
string ns = null;
Console.WriteLine($"Null string : {Cast<string>(ns)}\n");
int? ni = null;
Console.WriteLine($"Null int : {Cast<int>(ni)}\n");
long? nl = null;
Console.WriteLine($"Null long : {Cast<long>(nl)}\n");
double? ndbl = null;
Console.WriteLine($"Null double : {Cast<double>(ndbl)}\n");
decimal? nd = null;
Console.WriteLine($"Null decimal : {Cast<decimal>(nd)}\n");
string tb = "true";
Console.WriteLine($"Convert string to boolean : {Cast<bool>(tb)}\n");
bool? nb = null;
Console.WriteLine($"Null boolean : {Cast<bool>(nb)}\n");
// -----------------------
// From Microsoft examples
double d = -2.345;
int t = Cast<int>(d);
Console.WriteLine($"The double value {d} when converted to an int becomes {t}\n");
string s = "98/12/12";
DateTime dt = Cast<DateTime>(s);
Console.WriteLine($"The string value {s} when converted to a Date becomes {dt}\n");
// -----------------------
// ------------------------------------------
// Replace some character(s) with string type
string rs = "Replace this string with x to y.";
Console.WriteLine($"{Cast<string>(rs, " ", "_")}\n");
Console.WriteLine($"{Cast<string>("abcd", "", "abc")}\n");
Console.WriteLine($"{Cast<string>("", "", "abc")}\n");
string rs3 = "Replace this string from x to y.";
string ts = "string";
Console.WriteLine($"{Cast<string>(rs3, ts, ts.ToUpper())}\n");
Console.WriteLine($"Replace int character with string : {Cast<string>(vstr, "0", "1")}\n");
// ------------------------------------------
Console.WriteLine("Press any key to close...");
Console.ReadKey();
In addition, output results:
Adding int with loop : 65 from 10
Adding string with loop : 1012345678910 from 10
Multiply long : 1000000000000 from 1000000
Multiply double with loop : 4.479999963712E+23 from 123456789123456789
Multiply decimal with loop : 447999996371199995923200 from 123456789123456789
Null string :
Null int : 0
Null long : 0
Null double : 0
Null decimal : 0
Convert string to boolean : True
Null boolean : False
The double value -2.345 when converted to an int becomes -2
The string value 98/12/12 when converted to a Date becomes 1998-12-12 오전 12:00:00
Replace_this_string_with_x_to_y.
abcd
abc
Replace this STRING from x to y.
Replace int character with string : 1111111
Press any key to close...

public static class StringExtensions
{
public static TDest ConvertStringTo<TDest>(this string src)
{
if (src == null)
{
return default(TDest);
}
try
{
return ChangeType<TDest>(src);
}
catch
{
return default(TDest);
}
}
private static T ChangeType<T>(string value)
{
var t = typeof(T);
if (t.GetTypeInfo().IsGenericType && t.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
{
t = Nullable.GetUnderlyingType(t);
}
return (T)Convert.ChangeType(value, t);
}
}

Using runtime infrastructure to determine types and perform conversions between them as proposed by the other answers is very convenient and probably what you are looking for.
If, however, you need more control over your conversion (or rather parsing), e.g. because you get weird input formats that require pre-processing, may I suggest the following class.
It lets you provide a parser method for each type you register. The types from your question with their nullable cousins come pre-registered in the constructor, but you can also add any other method to the dictionary as your input data requires:
public delegate bool Parser<T>(string input, out T output);
public class Parsers
{
private delegate bool UntypedParser(string input, out object output);
private Dictionary<Type, UntypedParser> _parsersByType = new Dictionary<Type, UntypedParser>();
/// <summary>
/// Creates a <see cref="Parsers"/> instance pre-populated with parsers for the most common types.
/// </summary>
public static Parsers CreateDefault()
{
Parsers result = new Parsers();
result.AddParser<string>((string input, out string output) => { output = input; return true; });
result.AddParserForNullable<bool>(bool.TryParse);
result.AddParserForNullable<byte>(byte.TryParse);
result.AddParserForNullable<DateTime>(DateTime.TryParse);
result.AddParserForNullable<decimal>(decimal.TryParse);
result.AddParserForNullable<double>(double.TryParse);
result.AddParserForNullable<float>(float.TryParse);
result.AddParserForNullable<int>(int.TryParse);
result.AddParserForNullable<short>(short.TryParse);
return result;
}
/// <summary>
/// Registers a parser for the given type T
/// </summary>
public void AddParser<T>(Parser<T> parser)
{
_parsersByType[typeof(T)] = (string input, out object output) => ParseObject(parser, input, out output);
}
/// <summary>
/// Registers a parser for the given type T as well as <see cref="Nullable{T}"/>
/// </summary>
public void AddParserForNullable<T>(Parser<T> parser)
where T : struct
{
_parsersByType[typeof(T)] = (string input, out object output) => ParseObject(parser, input, out output);
_parsersByType[typeof(T?)] = (string input, out object output) => ParseNullable(parser, input, out output);
}
/// <summary>
/// For nullable types, return null when the input is an empty string or null.
/// </summary>
/// <remarks>This is not called for the string-parser. Meaning an empty string is not parsed into a null value.</remarks>
private bool ParseNullable<T>(Parser<T> parser, string input, out object output)
where T : struct
{
bool result;
if (string.IsNullOrEmpty(input))
{
result = true;
output = null;
}
else
{
result = ParseObject(parser, input, out output);
}
return result;
}
/// <summary>
/// Helper method to convert the typed output into an object (possibly boxing the value)
/// </summary>
private bool ParseObject<T>(Parser<T> parser, string input, out object output)
{
bool result = parser(input, out T typedOutput);
output = typedOutput;
return result;
}
/// <summary>
/// Finds the parser for the given target type and uses it to parse the input.
/// </summary>
public object Parse<T>(string input)
{
Type targetType = typeof(T);
object result;
if (!_parsersByType.TryGetValue(targetType, out UntypedParser parser))
{
throw new ArgumentException($"No parser defined for type '{targetType}'.");
}
else if (!parser(input, out result))
{
throw new ArgumentException($"Cannot parse '{targetType}' from input '{input}'.");
}
return result;
}
}

creating new element will delete first element in a list in C#

I have made a class -WhiteList - that contains data which is read from an xml file. I want to make a list of these elements, but after the first element is added to the list, I create a new element for data which erases the contens of the first element in the list. I.E. It seems that the new (elements) re-creates a reference to the element in the list.
Code snippet:
namespace WhiteList
{
public class WhiteListElement
{
private const byte EQL = 0;
private const byte CTN = 1;
private const byte COMMON_NAME = 0;
private const byte ORG = 1;
private const byte ORG_UNIT = 2;
private const byte LOC = 3;
private const byte STATE = 4;
private const byte COUNTRY = 5;
private static string[,] Subject;
private static string[,] Issuer;
private static string MinTlsLevel;
private static string Customer;
public WhiteListElement()
{
Subject = new string[6, 2];
Issuer = new string[6, 2];
Customer = "";
MinTlsLevel = "";
}
//---- set/get functions ---- example
public string GetCommonName(bool SubjectVal, bool Name)
{
if (true == SubjectVal) { if (true == Name) return Subject[COMMON_NAME, 0]; else return Subject[COMMON_NAME, 1]; }
else { if (true == Name) return Issuer[COMMON_NAME, 0]; else return Issuer[COMMON_NAME, 1]; }
}
public void SetCommonName(bool SubjectVal, bool Name, string NewValue)
{
if (true == SubjectVal) { if (true == Name) Subject[COMMON_NAME, 0] = NewValue; else Subject[COMMON_NAME, 1] = NewValue; }
else { if (true == Name) Issuer[COMMON_NAME, 0] = NewValue; else Issuer[COMMON_NAME, 1] = NewValue; }
}
}
class Program
{
public static void CreateWhiteList()
{
try
{
using (XmlReader reader = XmlReader.Create("WhiteList.xml"))
{
while (reader.Read())
{
if (reader.NodeType == XmlNodeType.Element)
{
if (reader.Name == "Kunder")
{
while (reader.Read())
{
if (reader.NodeType == XmlNodeType.Element)
{
XElement el = (XElement)XNode.ReadFrom(reader);
if (el != null)
{
WhiteListElement elem = new WhiteListElement();
var noderef = el.FirstNode;
elem.SetCustomer(el.Name.ToString());
while (noderef.NextNode != null)
{
noderef = noderef.NextNode;
string nodestring = noderef.ToString();
if (nodestring[0] == '<')
{
int startindx, stopindx;
string tag = nodestring.Substring(3);
string data;
tag = tag.Substring(0, tag.IndexOf('_'));
startindx = nodestring.IndexOf('\"') + 1;
stopindx = (nodestring.Substring(startindx)).IndexOf('\"');
data = nodestring.Substring(startindx, stopindx);
switch (tag)
{
case "CERTLVL": elem.SetCertLvl(data); break;
case "CN": if (nodestring[1] == 'S') elem.SetCommonName(true, true, data); if (nodestring[1] == 'I') elem.SetCommonName(false, true, data); break;
case "OU": if (nodestring[1] == 'S') elem.SetOrgUnit(true, true, data); if (nodestring[1] == 'I') elem.SetOrgUnit(false, true, data); break;
case "O": if (nodestring[1] == 'S') elem.SetOrg(true, true, data); if (nodestring[1] == 'I') elem.SetOrg(false, true, data); break;
case "L": if (nodestring[1] == 'S') elem.SetLocation(true, true, data); if (nodestring[1] == 'I') elem.SetLocation(false, true, data); break;
case "S": if (nodestring[1] == 'S') elem.SetState(true, true, data); if (nodestring[1] == 'I') elem.SetState(false, true, data); break;
case "C": if (nodestring[1] == 'S') elem.SetCountry(true, true, data); if (nodestring[1] == 'I') elem.SetCountry(false, true, data); break;
}
}
}
CustomerList.Add(elem);
}
}
}
}
}
}
}
}
catch (Exception ex) { Console.WriteLine(ex.Message); throw (ex); }
}
public static List<WhiteListElement>CustomerList = null;
static void Main(string[] args)
{
CustomerList = new List<WhiteListElement>();
CreateWhiteList();
}
}
}
------------- Code snippet end.
The problem occur after the first element is put in the list (CustomerList.Add(elem)) and returns to the line "WhiteListElement elem = new WhiteListElement();". This will delete the elements in CustomerList[0] and when putting data into elem afterwards, it is inserted into both elem and CustomerList[0], ending up with two identical elements in the list.
I have even tried to put an elem = null after adding elem just to try to erase the reference, but that didn't work
What am I doing wrong?
/Karsten

private static string[,] Subject;
private static string[,] Issuer;
private static string MinTlsLevel;
private static string Customer;
your problem come from here, static members are shared through all instances of a class thus when you edit the second , you erase the first, your class should be like this
public class WhiteListElement
{
private const byte EQL = 0;
private const byte CTN = 1;
private const byte COMMON_NAME = 0;
private const byte ORG = 1;
private const byte ORG_UNIT = 2;
private const byte LOC = 3;
private const byte STATE = 4;
private const byte COUNTRY = 5;
private string[,] Subject;
private string[,] Issuer;
private string MinTlsLevel;
private string Customer;
public WhiteListElement()
{
Subject = new string[6, 2];
Issuer = new string[6, 2];
Customer = "";
MinTlsLevel = "";
}
//---- set/get functions ---- example
public string GetCommonName(bool SubjectVal, bool Name)
{
if (true == SubjectVal) { if (true == Name) return Subject[COMMON_NAME, 0]; else return Subject[COMMON_NAME, 1]; }
else { if (true == Name) return Issuer[COMMON_NAME, 0]; else return Issuer[COMMON_NAME, 1]; }
}
public void SetCommonName(bool SubjectVal, bool Name, string NewValue)
{
if (true == SubjectVal) { if (true == Name) Subject[COMMON_NAME, 0] = NewValue; else Subject[COMMON_NAME, 1] = NewValue; }
else { if (true == Name) Issuer[COMMON_NAME, 0] = NewValue; else Issuer[COMMON_NAME, 1] = NewValue; }
}
}
edit : you can read more on static in the reference : https://msdn.microsoft.com/fr-fr/library/98f28cdx.aspx
especially:
While an instance of a class contains a separate copy of all instance fields of the class, there is only one copy of each static field.
It is not possible to use this to reference static methods or property accessors.

Firstly I think Boo's answer solves your problem, but I thought I would at least suggest a more object orientated approach that might make working with / debugging this problem easier in the future:
public class WhiteListElement
{
public string CertLevel;
public static WhiteListElement Create(XElement xml)
{
WhiteListElement element = new WhiteListElement();
element.CertLevel = xml.Attribute("CERTLVL").Value;
// Put data into object...
return element;
}
}
public class WhiteList
{
public List<WhiteListElement> Elements = new List<WhiteListElement>();
public static WhiteList Create(string xmlUri)
{
WhiteList whiteList = new WhiteList();
whiteList.Elements.AddRange(XElement.Load(xmlUri).Descendants("Kunder")
.Where(xmlElement => xmlElement != null)
.Select(xmlElement => WhiteListElement.Create(xmlElement)));
return whiteList;
}
}
Which can be used as:
WhiteList list = WhiteList.Create("WhiteList.xml");
string certLevel1 = list.Elements[0].CertLevel;
With the example XML:
<Title>
<Kunder CERTLVL="123"></Kunder>
<Kunder CERTLVL="456"></Kunder>
</Title >

De-serializing a flagged enum with a space results in SerializationException

When de-serializing a flagged enum that is decorated with a EnumMemberAttribute with a value containing a space a SerializationException is thrown. The space in the value is treated as a separator.
Is there a way to change the separator or put the values in quotes ? Or is there even a more simple solution ?
Options I already am considering are :
Replacing the flagged enum with a list of this enum type
Replacing the spaces with underscores
This is used in a WCF service, and I am
aware that enums in datacontracts by some are considered a bad thing.
So I am also thinking about losing the enum’s all together.
But I really feel that this should be something configurable or something other people already solved. But I can't find anything.
I have boiled the problem down to a simple unit test. The code below results in:
Message=Invalid enum value 'Test' cannot be deserialized into type 'UnitTests.TestEnum'. Ensure that the necessary enum values are present and are marked with EnumMemberAttribute attribute if the type has DataContractAttribute attribute.
Source=System.Runtime.Serialization
using System;
using System.IO;
using System.Runtime.Serialization;
using System.Xml;
using FluentAssertions;
using Microsoft.VisualStudio.TestTools.UnitTesting;
namespace UnitTests
{
[TestClass]
public class EnumSerizalizationTests
{
[TestMethod]
public void SerializingAndDesrializingAFlaggedEnumShouldResultInSameEnumValues()
{
//Arrange
var orgObject = new TestClass { Value = TestEnum.TestValue1 | TestEnum.TestValue2 };
//Act
var temp = DataContractSerializeObject(orgObject);
var newObject = DataContractDeSerializeObject<TestClass>(temp);
//Assert
newObject.ShouldBeEquivalentTo(orgObject, "Roundtripping serialization should result in same value");
}
public string DataContractSerializeObject<T>(T objectToSerialize)
{
using (var output = new StringWriter())
{
using (var writer = new XmlTextWriter(output) {Formatting = Formatting.Indented})
{
new DataContractSerializer(typeof (T)).WriteObject(writer, objectToSerialize);
return output.GetStringBuilder().ToString();
}
}
}
public T DataContractDeSerializeObject<T>(string stringToDeSerialize)
{
DataContractSerializer ser = new DataContractSerializer(typeof(T));
T result;
using (StringReader stringReader = new StringReader(stringToDeSerialize))
{
using (XmlReader xmlReader = XmlReader.Create(stringReader))
{
result = (T)ser.ReadObject(xmlReader);
}
}
return result;
}
}
[DataContract]
[KnownType(typeof(TestEnum))]
public class TestClass
{
[DataMember]
public TestEnum Value { get; set; }
}
[Flags]
[DataContract]
public enum TestEnum
{
[EnumMember(Value = "Test value one")]
TestValue1 = 1,
[EnumMember(Value = "Test value two")]
TestValue2 = 2,
[EnumMember]
TestValue3 = 4,
[EnumMember]
TestValue4 = 8,
}
}

You can't use space in values because DataContractSerializer uses it and it is hardcoded. See the source and the post. But if you really want to use space between words, then use one of the listed solutions:
The first way. Use other whitespace characters such as three-per-em space in values. But you will have another problem - there is no visual separator between values.
<TestClass xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/ConsoleApplication">
<Value>Test value one Test value two</Value>
</TestClass>
The second way is to use IDataContractSurrogate. This way will produce the XML listed below:
<TestClass xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/ConsoleApplication">
<Value i:type="EnumValueOfTestEnum9cBcd6LT">Test value one, Test value two</Value>
</TestClass>
How does it work? We will just wrap our enumeration in the process of serialization and unwrap in case of deserialization. In order to do that we should use IDataContractSurrogate:
new DataContractSerializerSettings()
{
DataContractSurrogate = new EnumSurrogate(),
KnownTypes = new Type[] { typeof(EnumValue<TestEnum>) }
};
public class EnumSurrogate : IDataContractSurrogate
{
#region IDataContractSurrogate Members
public object GetCustomDataToExport(Type clrType, Type dataContractType)
{
return null;
}
public object GetCustomDataToExport(MemberInfo memberInfo, Type dataContractType)
{
return null;
}
public Type GetDataContractType(Type type)
{
return type;
}
public object GetDeserializedObject(object obj, Type targetType)
{
IEnumValue enumValue = obj as IEnumValue;
if (enumValue!= null)
{ return enumValue.Value; }
return obj;
}
public void GetKnownCustomDataTypes(Collection<Type> customDataTypes)
{
}
public object GetObjectToSerialize(object obj, Type targetType)
{
if (obj != null)
{
Type type = obj.GetType();
if (type.IsEnum && Attribute.IsDefined(type, typeof(FlagsAttribute)))
{ return Activator.CreateInstance(typeof(EnumValue<>).MakeGenericType(type), obj); }
}
return obj;
}
public Type GetReferencedTypeOnImport(string typeName, string typeNamespace, object customData)
{
return null;
}
public CodeTypeDeclaration ProcessImportedType(CodeTypeDeclaration typeDeclaration, CodeCompileUnit compileUnit)
{
return null;
}
#endregion
}
public interface IEnumValue : IXmlSerializable
{
object Value { get; }
}
[Serializable]
public class EnumValue<T> : IEnumValue
where T : struct
{
#region Fields
private Enum value;
private static Type enumType;
private static long[] values;
private static string[] names;
private static bool isULong;
#endregion
#region Constructors
static EnumValue()
{
enumType = typeof(T);
if (!enumType.IsEnum)
{ throw new InvalidOperationException(); }
FieldInfo[] fieldInfos = enumType.GetFields(BindingFlags.Static | BindingFlags.Public);
values = new long[fieldInfos.Length];
names = new string[fieldInfos.Length];
isULong = Enum.GetUnderlyingType(enumType) == typeof(ulong);
for (int i = 0; i < fieldInfos.Length; i++)
{
FieldInfo fieldInfo = fieldInfos[i];
EnumMemberAttribute enumMemberAttribute = (EnumMemberAttribute)fieldInfo
.GetCustomAttributes(typeof(EnumMemberAttribute), false)
.FirstOrDefault();
IConvertible value = (IConvertible)fieldInfo.GetValue(null);
values[i] = (isULong)
? (long)value.ToUInt64(null)
: value.ToInt64(null);
names[i] = (enumMemberAttribute == null || string.IsNullOrEmpty(enumMemberAttribute.Value))
? fieldInfo.Name
: enumMemberAttribute.Value;
}
}
public EnumValue()
{
}
public EnumValue(Enum value)
{
this.value = value;
}
#endregion
#region IXmlSerializable Members
public XmlSchema GetSchema()
{
return null;
}
public void ReadXml(XmlReader reader)
{
string stringValue = reader.ReadElementContentAsString();
long longValue = 0;
int i = 0;
// Skip initial spaces
for (; i < stringValue.Length && stringValue[i] == ' '; i++) ;
// Read comma-delimited values
int startIndex = i;
int nonSpaceIndex = i;
int count = 0;
for (; i < stringValue.Length; i++)
{
if (stringValue[i] == ',')
{
count = nonSpaceIndex - startIndex + 1;
if (count > 1)
{ longValue |= ReadEnumValue(stringValue, startIndex, count); }
nonSpaceIndex = ++i;
// Skip spaces
for (; i < stringValue.Length && stringValue[i] == ' '; i++) ;
startIndex = i;
if (i == stringValue.Length)
{ break; }
}
else
{
if (stringValue[i] != ' ')
{ nonSpaceIndex = i; }
}
}
count = nonSpaceIndex - startIndex + 1;
if (count > 1)
longValue |= ReadEnumValue(stringValue, startIndex, count);
value = (isULong)
? (Enum)Enum.ToObject(enumType, (ulong)longValue)
: (Enum)Enum.ToObject(enumType, longValue);
}
public void WriteXml(XmlWriter writer)
{
long longValue = (isULong)
? (long)((IConvertible)value).ToUInt64(null)
: ((IConvertible)value).ToInt64(null);
int zeroIndex = -1;
bool noneWritten = true;
for (int i = 0; i < values.Length; i++)
{
long current = values[i];
if (current == 0)
{
zeroIndex = i;
continue;
}
if (longValue == 0)
{ break; }
if ((current & longValue) == current)
{
if (noneWritten)
{ noneWritten = false; }
else
{ writer.WriteString(","); }
writer.WriteString(names[i]);
longValue &= ~current;
}
}
if (longValue != 0)
{ throw new InvalidOperationException(); }
if (noneWritten && zeroIndex >= 0)
{ writer.WriteString(names[zeroIndex]); }
}
#endregion
#region IEnumValue Members
public object Value
{
get { return value; }
}
#endregion
#region Private Methods
private static long ReadEnumValue(string value, int index, int count)
{
for (int i = 0; i < names.Length; i++)
{
string name = names[i];
if (count == name.Length && string.CompareOrdinal(value, index, name, 0, count) == 0)
{ return values[i]; }
}
throw new InvalidOperationException();
}
#endregion
}
The third way is to emit dynamically the class, if base class has flagged Enum properties, replace them with string properties and use instances of the generated class as surrogates.

How to access a dynamic object's property dynamically (by variable)?

I have a class named Configurationwhich inherits from DynamicObject. It it a Dictionary<string, object>. In the constructor, it reads a text file and loads all the values from it splitted by =, so you can create dynamic configuration objects like this:
dynamic configuration = new Configuration("some_file.ini");
Here is my full class:
public sealed class Configuration : DynamicObject
{
private string Path { get; set; }
private Dictionary<string, object> Dictionary { get; set; }
public Configuration(string fileName)
{
this.Path = fileName;
this.Dictionary = new Dictionary<string, object>();
this.Populate();
}
~Configuration()
{
if (this.Dictionary != null)
{
this.Dictionary.Clear();
}
}
private void Populate()
{
using (StreamReader reader = new StreamReader(this.Path))
{
string line;
string currentSection = string.Empty;
while ((line = reader.ReadLine()) != null)
{
if (string.IsNullOrWhiteSpace(line))
{
continue;
}
if (line.StartsWith("[") && line.EndsWith("]"))
{
currentSection = line.Trim('[', ']');
}
else if (line.Contains("="))
{
this.Dictionary.Add(string.Format("{0}{1}{2}",
currentSection,
(currentSection != string.Empty) ? "_" : string.Empty,
line.Split('=')[0].Trim()),
ParseValue(line.Split('=')[1].Trim().Split(';')[0]));
}
}
}
}
private object ParseValue(string value)
{
if (string.IsNullOrWhiteSpace(value))
return string.Empty;
if (value.StartsWith("\"") && value.EndsWith("\""))
return value.Substring(1, value.Length - 1);
if (IsNumeric(value))
return Convert.ToInt32(value);
// TODO: FIXME Floating values (not to be confuse with IPAddress).
//if (IsFloating(value))
// return Convert.ToDouble(value);
if (string.Compare(value, "true", StringComparison.OrdinalIgnoreCase) == 0)
return true;
if (string.Compare(value, "false", StringComparison.OrdinalIgnoreCase) == 0)
return false;
return value;
}
public override bool TryGetMember(GetMemberBinder binder, out object result)
{
if (this.Dictionary.ContainsKey(binder.Name))
{
if (this.Dictionary[binder.Name] == null)
{
result = null;
}
else
{
result = this.Dictionary[binder.Name];
}
return true;
}
throw new ConfigurationException(binder.Name);
}
public override string ToString()
{
string result = this.Path + " [ ";
int processed = 0;
foreach (KeyValuePair<string, object> value in this.Dictionary)
{
result += value.Key;
processed++;
if (processed < this.Dictionary.Count)
{
result += ", ";
}
}
result += " ]";
return result;
}
private static bool IsNumeric(string value)
{
foreach (char c in value)
if (!char.IsDigit(c))
return false;
return true;
}
private static bool IsFloating(string value)
{
foreach (char c in value)
if (!char.IsDigit(c) && c != '.')
return false;
return true;
}
private class NullObject { }
}
Everything is working flawlessly. I've overriden TryGetMember and I'm returning the object based on the GetMemberBinder Name property. However, I'm facing a problem.
When I execute the following code:
string s = "some_config_key";
string d = configuration.s;
It retrieves the value of the key s rather than some_config_key, meaning that it doesn't evalute the value of the variable s. Is there a workaround for this?
Thanks.

C# dynamic features are partially compiled like the property/method access. To understand this lets take an example.
dynamic myVar = new { a=1, b="test" };
myVar.a += 1;
Here the C# type system would not test for the validity of the property while compilation, only at runtime the code is executed and if the property is not found it will through you runtime error.
So in your code the property access is already complied to access the property named "s" on the dynamic object "configuration".
In C# no-way you can do this not even in dynamically typed languages like python or javascript.
You have to use like this.
dynamic configuration = getConfig("path/to/file");
var myobj = configuration as IDictionary<string,object>;
string s = "config_key";
var value = myobj[s]; // this is correct.

C# implementation of deep/recursive object comparison in .net 3.5

I am looking for a C# specific , open source (or source code available) implementation of recursive, or deep, object comparison.
I currently have two graphs of live objects that I am looking to compare to each other, with the result of the comparison being a set of discrepancies in the graphs. The objects are instantiations of a set of classes that are known at run time (but not necessarily at compile time).
There is a specific requirement to be able to map from the discrepancies in the graphs, back to the objects containing the discrepancies.

I found a really nice, free implementation at www.kellermansoftware.com called Compare .NET Objects which can be found here. Highly recommended.
Appears to have relocated to github - most recent version is available here

This is a complex area; I've done some things like this at runtime, and it quickly gets messy. If possible, you might find that the simplest way to do this is to serialize the objects and compare the serialized form (perhaps xml-diff and XmlSerializer). This is complicated a little by the types not being known until runtime, but not hugely (you can always use new XmlSerializer(obj.GetType()) etc).
That would be my default approach, anyway.

Here's an NUnit 2.4.6 custom constraint we use for comparing complex graphs. It supports embedded collections, parent references, setting tolerance for numeric comparisons, identifying field names to ignore (even deep within the hierarchy), and decorating types to be always ignored.
I'm sure this code can be adapted to be used outside NUnit, the bulk of the code isn't dependent on NUnit.
We use this in thousands of unit tests.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
using NUnit.Framework;
using NUnit.Framework.Constraints;
namespace Tests
{
public class ContentsEqualConstraint : Constraint
{
private readonly object expected;
private Constraint failedEquality;
private string expectedDescription;
private string actualDescription;
private readonly Stack<string> typePath = new Stack<string>();
private string typePathExpanded;
private readonly HashSet<string> _ignoredNames = new HashSet<string>();
private readonly HashSet<Type> _ignoredTypes = new HashSet<Type>();
private readonly LinkedList<Type> _ignoredInterfaces = new LinkedList<Type>();
private readonly LinkedList<string> _ignoredSuffixes = new LinkedList<string>();
private readonly IDictionary<Type, Func<object, object, bool>> _predicates = new Dictionary<Type, Func<object, object, bool>>();
private bool _withoutSort;
private int _maxRecursion = int.MaxValue;
private readonly HashSet<VisitedComparison> _visitedObjects = new HashSet<VisitedComparison>();
private static readonly HashSet<string> _globallyIgnoredNames = new HashSet<string>();
private static readonly HashSet<Type> _globallyIgnoredTypes = new HashSet<Type>();
private static readonly LinkedList<Type> _globallyIgnoredInterfaces = new LinkedList<Type>();
private static object _regionalTolerance;
public ContentsEqualConstraint(object expectedValue)
{
expected = expectedValue;
}
public ContentsEqualConstraint Comparing<T>(Func<T, T, bool> predicate)
{
Type t = typeof (T);
if (predicate == null)
{
_predicates.Remove(t);
}
else
{
_predicates[t] = (x, y) => predicate((T) x, (T) y);
}
return this;
}
public ContentsEqualConstraint Ignoring(string fieldName)
{
_ignoredNames.Add(fieldName);
return this;
}
public ContentsEqualConstraint Ignoring(Type fieldType)
{
if (fieldType.IsInterface)
{
_ignoredInterfaces.AddFirst(fieldType);
}
else
{
_ignoredTypes.Add(fieldType);
}
return this;
}
public ContentsEqualConstraint IgnoringSuffix(string suffix)
{
if (string.IsNullOrEmpty(suffix))
{
throw new ArgumentNullException("suffix");
}
_ignoredSuffixes.AddLast(suffix);
return this;
}
public ContentsEqualConstraint WithoutSort()
{
_withoutSort = true;
return this;
}
public ContentsEqualConstraint RecursingOnly(int levels)
{
_maxRecursion = levels;
return this;
}
public static void GlobalIgnore(string fieldName)
{
_globallyIgnoredNames.Add(fieldName);
}
public static void GlobalIgnore(Type fieldType)
{
if (fieldType.IsInterface)
{
_globallyIgnoredInterfaces.AddFirst(fieldType);
}
else
{
_globallyIgnoredTypes.Add(fieldType);
}
}
public static IDisposable RegionalIgnore(string fieldName)
{
return new RegionalIgnoreTracker(fieldName);
}
public static IDisposable RegionalIgnore(Type fieldType)
{
return new RegionalIgnoreTracker(fieldType);
}
public static IDisposable RegionalWithin(object tolerance)
{
return new RegionalWithinTracker(tolerance);
}
public override bool Matches(object actualValue)
{
typePathExpanded = null;
actual = actualValue;
return Matches(expected, actualValue);
}
private bool Matches(object expectedValue, object actualValue)
{
bool matches = true;
if (!MatchesNull(expectedValue, actualValue, ref matches))
{
return matches;
}
// DatesEqualConstraint supports tolerance in dates but works as equal constraint for everything else
Constraint eq = new DatesEqualConstraint(expectedValue).Within(tolerance ?? _regionalTolerance);
if (eq.Matches(actualValue))
{
return true;
}
if (MatchesVisited(expectedValue, actualValue, ref matches))
{
if (MatchesDictionary(expectedValue, actualValue, ref matches) &&
MatchesList(expectedValue, actualValue, ref matches) &&
MatchesType(expectedValue, actualValue, ref matches) &&
MatchesPredicate(expectedValue, actualValue, ref matches))
{
MatchesFields(expectedValue, actualValue, eq, ref matches);
}
}
return matches;
}
private bool MatchesNull(object expectedValue, object actualValue, ref bool matches)
{
if (IsNullEquivalent(expectedValue))
{
expectedValue = null;
}
if (IsNullEquivalent(actualValue))
{
actualValue = null;
}
if (expectedValue == null && actualValue == null)
{
matches = true;
return false;
}
if (expectedValue == null)
{
expectedDescription = "null";
actualDescription = "NOT null";
matches = Failure;
return false;
}
if (actualValue == null)
{
expectedDescription = "not null";
actualDescription = "null";
matches = Failure;
return false;
}
return true;
}
private bool MatchesType(object expectedValue, object actualValue, ref bool matches)
{
Type expectedType = expectedValue.GetType();
Type actualType = actualValue.GetType();
if (expectedType != actualType)
{
try
{
Convert.ChangeType(actualValue, expectedType);
}
catch(InvalidCastException)
{
expectedDescription = expectedType.FullName;
actualDescription = actualType.FullName;
matches = Failure;
return false;
}
}
return true;
}
private bool MatchesPredicate(object expectedValue, object actualValue, ref bool matches)
{
Type t = expectedValue.GetType();
Func<object, object, bool> predicate;
if (_predicates.TryGetValue(t, out predicate))
{
matches = predicate(expectedValue, actualValue);
return false;
}
return true;
}
private bool MatchesVisited(object expectedValue, object actualValue, ref bool matches)
{
var c = new VisitedComparison(expectedValue, actualValue);
if (_visitedObjects.Contains(c))
{
matches = true;
return false;
}
_visitedObjects.Add(c);
return true;
}
private bool MatchesDictionary(object expectedValue, object actualValue, ref bool matches)
{
if (expectedValue is IDictionary && actualValue is IDictionary)
{
var expectedDictionary = (IDictionary)expectedValue;
var actualDictionary = (IDictionary)actualValue;
if (expectedDictionary.Count != actualDictionary.Count)
{
expectedDescription = expectedDictionary.Count + " item dictionary";
actualDescription = actualDictionary.Count + " item dictionary";
matches = Failure;
return false;
}
foreach (DictionaryEntry expectedEntry in expectedDictionary)
{
if (!actualDictionary.Contains(expectedEntry.Key))
{
expectedDescription = expectedEntry.Key + " exists";
actualDescription = expectedEntry.Key + " does not exist";
matches = Failure;
return false;
}
if (CanRecurseFurther)
{
typePath.Push(expectedEntry.Key.ToString());
if (!Matches(expectedEntry.Value, actualDictionary[expectedEntry.Key]))
{
matches = Failure;
return false;
}
typePath.Pop();
}
}
matches = true;
return false;
}
return true;
}
private bool MatchesList(object expectedValue, object actualValue, ref bool matches)
{
if (!(expectedValue is IList && actualValue is IList))
{
return true;
}
var expectedList = (IList) expectedValue;
var actualList = (IList) actualValue;
if (!Matches(expectedList.Count, actualList.Count))
{
matches = false;
}
else
{
if (CanRecurseFurther)
{
int max = expectedList.Count;
if (max != 0 && !_withoutSort)
{
SafeSort(expectedList);
SafeSort(actualList);
}
for (int i = 0; i < max; i++)
{
typePath.Push(i.ToString());
if (!Matches(expectedList[i], actualList[i]))
{
matches = false;
return false;
}
typePath.Pop();
}
}
matches = true;
}
return false;
}
private void MatchesFields(object expectedValue, object actualValue, Constraint equalConstraint, ref bool matches)
{
Type expectedType = expectedValue.GetType();
FieldInfo[] fields = expectedType.GetFields(BindingFlags.Instance | BindingFlags.NonPublic);
// should have passed the EqualConstraint check
if (expectedType.IsPrimitive ||
expectedType == typeof(string) ||
expectedType == typeof(Guid) ||
fields.Length == 0)
{
failedEquality = equalConstraint;
matches = Failure;
return;
}
if (expectedType == typeof(DateTime))
{
var expectedDate = (DateTime)expectedValue;
var actualDate = (DateTime)actualValue;
if (Math.Abs((expectedDate - actualDate).TotalSeconds) > 3.0)
{
failedEquality = equalConstraint;
matches = Failure;
return;
}
matches = true;
return;
}
if (CanRecurseFurther)
{
while(true)
{
foreach (FieldInfo field in fields)
{
if (!Ignore(field))
{
typePath.Push(field.Name);
if (!Matches(GetValue(field, expectedValue), GetValue(field, actualValue)))
{
matches = Failure;
return;
}
typePath.Pop();
}
}
expectedType = expectedType.BaseType;
if (expectedType == null)
{
break;
}
fields = expectedType.GetFields(BindingFlags.Instance | BindingFlags.NonPublic);
}
}
matches = true;
return;
}
private bool Ignore(FieldInfo field)
{
if (_ignoredNames.Contains(field.Name) ||
_ignoredTypes.Contains(field.FieldType) ||
_globallyIgnoredNames.Contains(field.Name) ||
_globallyIgnoredTypes.Contains(field.FieldType) ||
field.GetCustomAttributes(typeof (IgnoreContentsAttribute), false).Length != 0)
{
return true;
}
foreach(string ignoreSuffix in _ignoredSuffixes)
{
if (field.Name.EndsWith(ignoreSuffix))
{
return true;
}
}
foreach (Type ignoredInterface in _ignoredInterfaces)
{
if (ignoredInterface.IsAssignableFrom(field.FieldType))
{
return true;
}
}
return false;
}
private static bool Failure
{
get
{
return false;
}
}
private static bool IsNullEquivalent(object value)
{
return value == null ||
value == DBNull.Value ||
(value is int && (int) value == int.MinValue) ||
(value is double && (double) value == double.MinValue) ||
(value is DateTime && (DateTime) value == DateTime.MinValue) ||
(value is Guid && (Guid) value == Guid.Empty) ||
(value is IList && ((IList)value).Count == 0);
}
private static object GetValue(FieldInfo field, object source)
{
try
{
return field.GetValue(source);
}
catch(Exception ex)
{
return ex;
}
}
public override void WriteMessageTo(MessageWriter writer)
{
if (TypePath.Length != 0)
{
writer.WriteLine("Failure on " + TypePath);
}
if (failedEquality != null)
{
failedEquality.WriteMessageTo(writer);
}
else
{
base.WriteMessageTo(writer);
}
}
public override void WriteDescriptionTo(MessageWriter writer)
{
writer.Write(expectedDescription);
}
public override void WriteActualValueTo(MessageWriter writer)
{
writer.Write(actualDescription);
}
private string TypePath
{
get
{
if (typePathExpanded == null)
{
string[] p = typePath.ToArray();
Array.Reverse(p);
var text = new StringBuilder(128);
bool isFirst = true;
foreach(string part in p)
{
if (isFirst)
{
text.Append(part);
isFirst = false;
}
else
{
int i;
if (int.TryParse(part, out i))
{
text.Append("[" + part + "]");
}
else
{
text.Append("." + part);
}
}
}
typePathExpanded = text.ToString();
}
return typePathExpanded;
}
}
private bool CanRecurseFurther
{
get
{
return typePath.Count < _maxRecursion;
}
}
private static bool SafeSort(IList list)
{
if (list == null)
{
return false;
}
if (list.Count < 2)
{
return true;
}
try
{
object first = FirstNonNull(list) as IComparable;
if (first == null)
{
return false;
}
if (list is Array)
{
Array.Sort((Array)list);
return true;
}
return CallIfExists(list, "Sort");
}
catch
{
return false;
}
}
private static object FirstNonNull(IEnumerable enumerable)
{
if (enumerable == null)
{
throw new ArgumentNullException("enumerable");
}
foreach (object item in enumerable)
{
if (item != null)
{
return item;
}
}
return null;
}
private static bool CallIfExists(object instance, string method)
{
if (instance == null)
{
throw new ArgumentNullException("instance");
}
if (String.IsNullOrEmpty(method))
{
throw new ArgumentNullException("method");
}
Type target = instance.GetType();
MethodInfo m = target.GetMethod(method, new Type[0]);
if (m != null)
{
m.Invoke(instance, null);
return true;
}
return false;
}
#region VisitedComparison Helper
private class VisitedComparison
{
private readonly object _expected;
private readonly object _actual;
public VisitedComparison(object expected, object actual)
{
_expected = expected;
_actual = actual;
}
public override int GetHashCode()
{
return GetHashCode(_expected) ^ GetHashCode(_actual);
}
private static int GetHashCode(object o)
{
if (o == null)
{
return 0;
}
return o.GetHashCode();
}
public override bool Equals(object obj)
{
if (obj == null)
{
return false;
}
if (obj.GetType() != typeof(VisitedComparison))
{
return false;
}
var other = (VisitedComparison) obj;
return _expected == other._expected &&
_actual == other._actual;
}
}
#endregion
#region RegionalIgnoreTracker Helper
private class RegionalIgnoreTracker : IDisposable
{
private readonly string _fieldName;
private readonly Type _fieldType;
public RegionalIgnoreTracker(string fieldName)
{
if (!_globallyIgnoredNames.Add(fieldName))
{
_globallyIgnoredNames.Add(fieldName);
_fieldName = fieldName;
}
}
public RegionalIgnoreTracker(Type fieldType)
{
if (!_globallyIgnoredTypes.Add(fieldType))
{
_globallyIgnoredTypes.Add(fieldType);
_fieldType = fieldType;
}
}
public void Dispose()
{
if (_fieldName != null)
{
_globallyIgnoredNames.Remove(_fieldName);
}
if (_fieldType != null)
{
_globallyIgnoredTypes.Remove(_fieldType);
}
}
}
#endregion
#region RegionalWithinTracker Helper
private class RegionalWithinTracker : IDisposable
{
public RegionalWithinTracker(object tolerance)
{
_regionalTolerance = tolerance;
}
public void Dispose()
{
_regionalTolerance = null;
}
}
#endregion
#region IgnoreContentsAttribute
[AttributeUsage(AttributeTargets.Field)]
public sealed class IgnoreContentsAttribute : Attribute
{
}
#endregion
}
public class DatesEqualConstraint : EqualConstraint
{
private readonly object _expected;
public DatesEqualConstraint(object expectedValue) : base(expectedValue)
{
_expected = expectedValue;
}
public override bool Matches(object actualValue)
{
if (tolerance != null && tolerance is TimeSpan)
{
if (_expected is DateTime && actualValue is DateTime)
{
var expectedDate = (DateTime) _expected;
var actualDate = (DateTime) actualValue;
var toleranceSpan = (TimeSpan) tolerance;
if ((actualDate - expectedDate).Duration() <= toleranceSpan)
{
return true;
}
}
tolerance = null;
}
return base.Matches(actualValue);
}
}
}

This is actually a simple process. Using reflection you can compare each field on the object.
public static Boolean ObjectMatches(Object x, Object y)
{
if (x == null && y == null)
return true;
else if ((x == null && y != null) || (x != null && y == null))
return false;
Type tx = x.GetType();
Type ty = y.GetType();
if (tx != ty)
return false;
foreach(FieldInfo field in tx.GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly))
{
if (field.FieldType.IsValueType && (field.GetValue(x).ToString() != field.GetValue(y).ToString()))
return false;
else if (field.FieldType.IsClass && !ObjectMatches(field.GetValue(x), field.GetValue(y)))
return false;
}
return true;
}

Using the Nuget suggested by Jesse and this code I managed to compare two objects with great results.
using KellermanSoftware.CompareNetObjects;
using System;
namespace MyProgram.UnitTestHelper
{
public class ObjectComparer
{
public static bool ObjectsHaveSameValues(object first, object second)
{
CompareLogic cl = new CompareLogic();
ComparisonResult result = cl.Compare(first, second);
if (!result.AreEqual)
Console.WriteLine(result.DifferencesString);
return result.AreEqual;
}
}
}

Here is a simple comparer that we've used with unit testing to assert that two objects have equal properties. It's a mash-up of ideas found in various articles, and handles circular references.
public static class TestHelper
{
public static void AssertAreEqual(Object expected, Object actual, String name)
{
// Start a new check with an empty list of actual objects checked
// The list of actual objects checked is used to ensure that circular references don't result in infinite recursion
List<Object> actualObjectsChecked = new List<Object>();
AssertAreEqual(expected, actual, name, actualObjectsChecked);
}
private static void AssertAreEqual(Object expected, Object actual, String name, List<Object> actualObjectsChecked)
{
// Just return if already checked the actual object
if (actualObjectsChecked.Contains(actual))
{
return;
}
actualObjectsChecked.Add(actual);
// If both expected and actual are null, they are considered equal
if (expected == null && actual == null)
{
return;
}
if (expected == null && actual != null)
{
Assert.Fail(String.Format("The actual value of {0} was not null when null was expected.", name));
}
if (expected != null && actual == null)
{
Assert.Fail(String.Format("The actual value of {0} was null when an instance was expected.", name));
}
// Get / check type info
// Note: GetType always returns instantiated (i.e. most derived) type
Type expectedType = expected.GetType();
Type actualType = actual.GetType();
if (expectedType != actualType)
{
Assert.Fail(String.Format("The actual type of {0} was not the same as the expected type.", name));
}
// If expected is a Primitive, Value, or IEquatable type, assume Equals is sufficient to check
// Note: Every IEquatable type should have also overridden Object.Equals
if (expectedType.IsPrimitive || expectedType.IsValueType || expectedType.IsIEquatable())
{
Assert.IsTrue(expected.Equals(actual), "The actual {0} is not equal to the expected.", name);
return;
}
// If expected is an IEnumerable type, assume comparing enumerated items is sufficient to check
IEnumerable<Object> expectedEnumerable = expected as IEnumerable<Object>;
IEnumerable<Object> actualEnumerable = actual as IEnumerable<Object>;
if ((expectedEnumerable != null) && (actualEnumerable != null))
{
Int32 actualEnumerableCount = actualEnumerable.Count();
Int32 expectedEnumerableCount = expectedEnumerable.Count();
// Check size first
if (actualEnumerableCount != expectedEnumerableCount)
{
Assert.Fail(String.Format("The actual number of enumerable items in {0} did not match the expected number.", name));
}
// Check items in order, assuming order is the same
for (int i = 0; i < actualEnumerableCount; ++i)
{
AssertAreEqual(expectedEnumerable.ElementAt(i), actualEnumerable.ElementAt(i), String.Format("{0}[{1}]", name, i), actualObjectsChecked);
}
return;
}
// If expected is not a Primitive, Value, IEquatable, or Ienumerable type, assume comparing properties is sufficient to check
// Iterate through properties
foreach (PropertyInfo propertyInfo in actualType.GetProperties(BindingFlags.Instance | BindingFlags.Public))
{
// Skip properties that can't be read or require parameters
if ((!propertyInfo.CanRead) || (propertyInfo.GetIndexParameters().Length != 0))
{
continue;
}
// Get properties from both
Object actualProperty = propertyInfo.GetValue(actual, null);
Object expectedProperty = propertyInfo.GetValue(expected, null);
AssertAreEqual(expectedProperty, actualProperty, String.Format("{0}.{1}", name, propertyInfo.Name), actualObjectsChecked);
}
}
public static Boolean IsIEquatable(this Type type)
{
return type.GetInterfaces().Any(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(IEquatable<>));
}
}