Get a complete string representation of an object (like in the Immediate Window in Visual Studio)

Question

Given the following example class:

public class MyClass
{
    public string S { get; set; }
    public int I { get; set; }
    public DateTime D { get; set; }
    private float F { get; set; }
    private long l;

    public MyClass()
    {
        S = "foo";
        I = 42;
        D = new DateTime(2011, 11, 11);
        F = 3.14f;
        l = 12435;
    }
}

If I in my application have an instance myClass of this class, step through the code in debug mode (Visual Studio 2010), and at some point types myClass into the Immediate Window, the following is displayed:

{MyClass}
    D: {11.11.2011 00:00:00}
    F: 3.14
    I: 42
    l: 12435
    S: "foo"

Getting such a string representation of the object and all its values could be very useful for logging purposes. Is there a nice and easy way to achieve this?

I guess the Immediate Window uses reflection to loop over all fields and properties, but I thought I'd ask just in case there already exists some utility function or anything to do it.

@Saeed Neamati: thanks, your tip helped me google a bit more, which lead me to ObjectDumper.cs (http://code.msdn.microsoft.com/LINQ-Sample-Queries-13a42a54/sourcecode?fileId=23655&pathId=2145124756). — Julian, Jul 15 '11 at 06:34
Possible duplicate of [What is the best way to dump entire objects to a log in C#?](http://stackoverflow.com/questions/360277/what-is-the-best-way-to-dump-entire-objects-to-a-log-in-c) — StayOnTarget, Apr 28 '17 at 16:56

Grant Winney · Accepted Answer · 2014-05-25T12:41:00.547

13

This will store all fields in a dictionary (ensuring they can be read first):

public static Dictionary<string, object> GeneratePropertiesDictionary(object myClass)
{
    return myClass.GetType()
                  .GetProperties()
                  .Where(p => p.CanRead)
                  .ToDictionary(p => p.Name, p => p.GetValue(myClass, null));
}

You could easily modify this to append each name/value to a StringBuilder object instead of a dictionary though, and dump that to a file.

edited May 25 '14 at 12:41

answered Jul 14 '11 at 14:53

Grant Winney

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2

Thanks for sharing your function. I was hoping there perhaps was some existing utility functions one could use, but it seems like making your own using reflection is the way to go. I might not be using your code directly, but instead I think I'll make a modified version of ObjectDumper.cs (http://code.msdn.microsoft.com/LINQ-Sample-Queries-13a42a54/sourcecode?fileId=23655&pathId=2145124756) from the LINQ Sample Queries at MSDN. – Julian Jul 15 '11 at 06:33

score 4 · Answer 2 · answered Jul 14 '11 at 14:50

4

If you want a serialized version of an object, I would probably use the JavaScriptSerializer in your logging:

public void LogObject(object obj)
{
    var serializer = new JavaScriptSerializer();
    var objString = serializer.Serialize(obj);

    WriteLog(objString);
}

answered Jul 14 '11 at 14:50

Justin Niessner

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*If* the object can be serialized. – George Johnston Jul 14 '11 at 14:53
I'm in a console application, so I don't have access to JavaScriptSerializer (it says _Provides serialization and deserialization functionality for AJAX-enabled applications._ in the documentation). – Julian Jul 14 '11 at 14:55
2

@Nailuj - That may be where it fits into the framework, but it can be used absolutely anywhere as long you as you include the reference. – Justin Niessner Jul 14 '11 at 14:57
I just tested this, and it doesn't seem to include the private fields/properties when serializing. It is a nice and easy solution, but because of this: not completely optimal. – Julian Jul 14 '11 at 15:10

score 1 · Answer 3 · answered Jul 14 '11 at 14:48

1

You can use Reflection and iterate over all fields and properties, calling ToString() on each result. If the current field/property is a class/struct, you can do that recursively, if you want to.

Secondly, some classes use the DebuggerDisplayAttribute, though you would need to parse that AFAICT.

answered Jul 14 '11 at 14:48

Daniel Rose

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Thanks :) But as I said in the question, I assumed reflection is what the Immediate Window is using, but I wondered (since this is a thing I suppose would be useful for many), if there already exists some kind of utility function to do this. – Julian Jul 14 '11 at 14:50
2

You want to be careful doing this recursively as you may end up in an infinite loop... – Jeremy McGee Jul 14 '11 at 14:51
@Nailuj: The Immediate Window uses the default visualizer for objects, unless a more specific visualizer for the type has been defined. For more info about visualizers, see http://msdn.microsoft.com/en-us/library/zayyhzts.aspx. – Jimmy Jul 14 '11 at 14:55

Jimmy · Answer 4 · 2011-07-14T15:16:07.620

0

If you just want to log (i.e. print) a representation of the object, override the ToString method.

ToString is the major formatting method in the .NET Framework. It converts an object to its string representation so that it is suitable for display.

Also, if you wanted to provide multiple ways to output the string (e.g. to support a verbose or minimal option), you can also look into implementing IFormattable.

edited Jul 14 '11 at 15:16

answered Jul 14 '11 at 14:53

Jimmy

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Yes, that is of course an option. But my goal is to _not_ have to override the ToString() method for every single class I create. – Julian Jul 14 '11 at 14:56
@Nailuj - Except overriding the ToString method is the more elgegant way of doing what you want besides using a virtualizer ( only supported by managed languages ) – Security Hound Jul 14 '11 at 15:04
1

@Ramhound: I'd say that depends. You might often want the ToString method to give a "sensible" representation of your object, and not necessarily all properties. But for debugging/logging purpouses, you might want something like "ToDebugString" that gives you exactly this. And on a side-note: why did somebody -1 this? It's not really a wrong answer... And explanation from that person would be nice! – Julian Jul 14 '11 at 15:08
@Nailuj: good point about wanting multiple forms of ToString. I added a note about IFormattable, which provides support for formatting options such as with DateTime. Even if it's not the answer you're looking for. ;) – Jimmy Jul 14 '11 at 15:17
In a majority of cases, the data type you're trying to write to, say, a debug log is defined by a third-party library so directly adding a ToString() implementation is not possible. I'm not so sure using an extension method is a very good idea either. ToString() is for presenting to a user, not a debugger. Python separates these two use cases in the str() and repr() functions, and Rust also has a similar distinction. – flodin Oct 10 '18 at 10:10

Get a complete string representation of an object (like in the Immediate Window in Visual Studio)

4 Answers4