In C#, how do you one-way serialize the unserializable?

Question

Oftentimes, I need to serialize an object, either for logging or debugging. This is a one-way serialization -- I don't need to get it back out later, I just need to turn an object into a string to write it somewhere.

Yes, yes -- this is why you should always override the ToString method. I know this. But I'm often dealing with objects I didn't write and can't change. Additionally, I don't want to have to write and update a ToString method for every class I write.

XML serialization offers a seemingly perfect solution -- just flatten that object out into XML. But there are so many limitations, specifically that you can't serialize IDictionary, and you have to have a parameterless constructor. I can get around these in my classes, but -- again -- I'm often working with other people's classes.

So, what's the solution to getting an comprehensive string representation of an object? Is there something simple that I'm missing?

Answer 1

How about an extension method with your own logic (and maybe some Reflection)?

public static class SerializerExtension {     public static String OneWaySerialize(this Object obj)     {         if (Object.ReferenceEquals(obj, null))         {             return "NULL";         }         if (obj.GetType().IsPrimitive || obj.GetType() == typeof(String))         {             if (obj is String)                 return String.Format("\"{0}\"", obj);             if (obj is Char)                 return String.Format("'{0}'", obj);             return obj.ToString();         }          StringBuilder builder = new StringBuilder();         Type objType = obj.GetType();         if (IsEnumerableType(objType))         {             builder.Append("[");              IEnumerator enumerator = ((IEnumerable)obj).GetEnumerator();             Boolean moreElements = enumerator.MoveNext();             while (moreElements)             {                 builder.Append(enumerator.Current.OneWaySerialize());                 moreElements = enumerator.MoveNext();                 if (moreElements)                 {                     builder.Append(",");                 }             }              builder.Append("]");         }         else         {             builder.AppendFormat("{0} {{ ", IsAnonymousType(objType) ? "new" : objType.Name);              PropertyInfo[] properties = objType.GetProperties();             for (Int32 p = properties.Length; p > 0; p--)             {                 PropertyInfo prop = properties[p-1];                 String propName = prop.Name;                 Object propValue = prop.GetValue(obj, null);                 builder.AppendFormat("{0} = {1}", propName, propValue.OneWaySerialize());                 if (p > 1)                 {                     builder.Append(", ");                 }             }              builder.Append(" }");         }          return builder.ToString();     }      // http://stackoverflow.com/a/2483054/298053     private static Boolean IsAnonymousType(Type type)     {         if (type == null)         {             return false;         }         return Attribute.IsDefined(type, typeof(System.Runtime.CompilerServices.CompilerGeneratedAttribute), false)             && type.IsGenericType && type.Name.Contains("AnonymousType")             && (type.Name.StartsWith("<>") || type.Name.StartsWith("VB$"))             && (type.Attributes & TypeAttributes.NotPublic) == TypeAttributes.NotPublic;     }      private static Boolean IsEnumerableType(Type type)     {         if (type == null)         {             return false;         }         foreach (Type intType in type.GetInterfaces())         {             if (intType.GetInterface("IEnumerable") != null || (intType.IsGenericType && intType.GetGenericTypeDefinition() == typeof(IEnumerable<>)))             {                 return true;             }         }         return false;     } } 

Call it like so:

someDefinedObject.OneWaySerialize(); 

Revisisons

1. Initial version
2. Updated 12.26.2012
   • Added check for IEnumerable (thanks aboveyou00)
   • Added check for anonymous type (and just label it "new" when output)

Answer 2

If you're comfortable serializing to JSON, Json.NET is a great solution to this problem.