What is the best way to dump entire objects to a l

Question

So for viewing a current object's state at runtime, I really like what the Visual Studio Immediate window gives me. Just doing a simple

? objectname

Will give me a nicely formatted 'dump' of the object.

Is there an easy way to do this in code, so I can do something similar when logging?

Answer 1

I'm certain there are better ways of doing this, but I have in the past used a method something like the following to serialize an object into a string that I can log:

  private string ObjectToXml(object output)
  {
     string objectAsXmlString;

     System.Xml.Serialization.XmlSerializer xs = new System.Xml.Serialization.XmlSerializer(output.GetType());
     using (System.IO.StringWriter sw = new System.IO.StringWriter())
     {
        try
        {
           xs.Serialize(sw, output);
           objectAsXmlString = sw.ToString();
        }
        catch (Exception ex)
        {
           objectAsXmlString = ex.ToString();
        }
     }

     return objectAsXmlString;
  }

You'll see that the method might also return the exception rather than the serialized object, so you'll want to ensure that the objects you want to log are serializable.

Answer 2

Here is a stupidly simple way to write a flat object, nicely formatted:

using Newtonsoft.Json.Linq;

Debug.WriteLine("The object is " + JObject.FromObject(theObjectToDump).ToString());

What's going on is that the object is first converted to a JSON internal representation by JObject.FromObject, and then converted to JSON string by ToString. (And of course a JSON string is a very nice representation of a simple object, especially since ToString will include newlines and indents.) The "ToString" is of course extraneous (as it's implied by using + to concat a string and an object), but I kinda like to specify it here.

Answer 3

Based on @engineforce answer, I made this class that I'm using in a PCL project of a Xamarin Solution:

/// <summary>
/// Based on: https://stackoverflow.com/a/42264037/6155481
/// </summary>
public class ObjectDumper
{
    public static string Dump(object obj)
    {
        return new ObjectDumper().DumpObject(obj);
    }

    StringBuilder _dumpBuilder = new StringBuilder();

    string DumpObject(object obj)
    {
        DumpObject(obj, 0);
        return _dumpBuilder.ToString();
    }

    void DumpObject(object obj, int nestingLevel)
    {
        var nestingSpaces = "".PadLeft(nestingLevel * 4);

        if (obj == null)
        {
            _dumpBuilder.AppendFormat("{0}null\n", nestingSpaces);
        }
        else if (obj is string || obj.GetType().GetTypeInfo().IsPrimitive || obj.GetType().GetTypeInfo().IsEnum)
        {
            _dumpBuilder.AppendFormat("{0}{1}\n", nestingSpaces, obj);
        }
        else if (ImplementsDictionary(obj.GetType()))
        {
            using (var e = ((dynamic)obj).GetEnumerator())
            {
                var enumerator = (IEnumerator)e;
                while (enumerator.MoveNext())
                {
                    dynamic p = enumerator.Current;

                    var key = p.Key;
                    var value = p.Value;
                    _dumpBuilder.AppendFormat("{0}{1} ({2})\n", nestingSpaces, key, value != null ? value.GetType().ToString() : "<null>");
                    DumpObject(value, nestingLevel + 1);
                }
            }
        }
        else if (obj is IEnumerable)
        {
            foreach (dynamic p in obj as IEnumerable)
            {
                DumpObject(p, nestingLevel);
            }
        }
        else
        {
            foreach (PropertyInfo descriptor in obj.GetType().GetRuntimeProperties())
            {
                string name = descriptor.Name;
                object value = descriptor.GetValue(obj);

                _dumpBuilder.AppendFormat("{0}{1} ({2})\n", nestingSpaces, name, value != null ? value.GetType().ToString() : "<null>");

                // TODO: Prevent recursion due to circular reference
                if (name == "Self" && HasBaseType(obj.GetType(), "NSObject"))
                {
                    // In ObjC I need to break the recursion when I find the Self property
                    // otherwise it will be an infinite recursion
                    Console.WriteLine($"Found Self! {obj.GetType()}");
                }
                else
                {
                    DumpObject(value, nestingLevel + 1);
                }
            }
        }
    }

    bool HasBaseType(Type type, string baseTypeName)
    {
        if (type == null) return false;

        string typeName = type.Name;

        if (baseTypeName == typeName) return true;

        return HasBaseType(type.GetTypeInfo().BaseType, baseTypeName);
    }

    bool ImplementsDictionary(Type t)
    {
        return t is IDictionary;
    }
}

Answer 4

I have a T.Dump() extension method that does exactly this, recursively dumps all properties of any type in a nice readable format.

Example usage:

var model = new TestModel();
Console.WriteLine(model.Dump());

and output:

{
    Int: 1,
    String: One,
    DateTime: 2010-04-11,
    Guid: c050437f6fcd46be9b2d0806a0860b3e,
    EmptyIntList: [],
    IntList:
    [
        1,
        2,
        3
    ],
    StringList:
    [
        one,
        two,
        three
    ],
    StringIntMap:
    {
        a: 1,
        b: 2,
        c: 3
    }
}

Answer 5

You could use reflection and loop through all the object properties, then get their values and save them to the log. The formatting is really trivial (you could use \t to indent an objects properties and its values):

MyObject
    Property1 = value
    Property2 = value2
    OtherObject
       OtherProperty = value ...

Answer 6

What I like doing is overriding ToString() so that I get more useful output beyond the type name. This is handy in the debugger, you can see the information you want about an object without needing to expand it.