Dynamic override of ToString() using Reflection

Question

I generally override the ToString() method to output the property names and the values associated to them. I got a bit tired of writing these by hand so I'm looking for a dynamic solution.

Main:

TestingClass tc = new TestingClass()
{
    Prop1 = "blah1",
    Prop2 = "blah2"
};
Console.WriteLine(tc.ToString());
Console.ReadLine();

TestingClass:

public class TestingClass
{
    public string Prop1 { get; set; }//properties
    public string Prop2 { get; set; }
    public void Method1(string a) { }//method
    public TestingClass() { }//const
    public override string ToString()
    {
        StringBuilder sb = new StringBuilder();
        foreach (Type type in System.Reflection.Assembly.GetExecutingAssembly().GetTypes())
        {
            foreach (System.Reflection.PropertyInfo property in type.GetProperties())
            {
                sb.Append(property.Name);
                sb.Append(": ");
                sb.Append(this.GetType().GetProperty(property.Name).Name);
                sb.Append(System.Environment.NewLine);
            }
        }
        return sb.ToString();
    }
}

This currently outputs:

Prop1: System.String Prop1
Prop2: System.String Prop2

Desired Output:

Prop1: blah1
Prop2: blah2

I'm open for other solutions, it doesn't have to use reflection, it just has to produce the desired output.

You should not use `ToString` to return all property values in general. Instead you could provide a method `GetPropertyInfo` that does it if you want. — Tim Schmelter, Feb 15 '12 at 18:48

Simon Woker · Accepted Answer · 2012-02-16T09:31:41.863

This works for me:

public class TestingClass
{
    public string Prop1 { get; set; }//properties
    public string Prop2 { get; set; }
    public void Method1(string a) { }//method
    public TestingClass() { }//const
    public override string ToString()
    {
        StringBuilder sb = new StringBuilder();
        foreach (System.Reflection.PropertyInfo property in this.GetType().GetProperties())
        {
            sb.Append(property.Name);
            sb.Append(": ");
            if (property.GetIndexParameters().Length > 0)
            {
                sb.Append("Indexed Property cannot be used");
            }
            else
            {
                sb.Append(property.GetValue(this, null));
            }

            sb.Append(System.Environment.NewLine);
        }

        return sb.ToString();
    }
}

To make it available everywhere you can create an Extension.
It's not possible to override methods in an Extension, but still it should simplify your life.

public static class MyExtensions
{
    public static string ToStringExtension(this object obj)
    {
        StringBuilder sb = new StringBuilder();
        foreach (System.Reflection.PropertyInfo property in obj.GetType().GetProperties())
        {

            sb.Append(property.Name);
            sb.Append(": ");
            if (property.GetIndexParameters().Length > 0)
            {
                sb.Append("Indexed Property cannot be used");
            }
            else
            {
                sb.Append(property.GetValue(obj, null));
            }

            sb.Append(System.Environment.NewLine);
        }

        return sb.ToString();
    }
}

You can then call ToStringExtension() on every object.
Downside is, it doesn't work perfectly for lists etc., example:

var list = new List<string>();
// (filling list ommitted)
list.ToStringExtension();
// output:
// Capacity: 16
// Count: 11
// Item: Indexed Property cannot be used

What's about perfomance using reflection? What's about Hanselman implementation http://www.hanselman.com/blog/ASmarterOrPureEvilToStringWithExtensionMethods.aspx ? — Kiquenet, Dec 02 '13 at 11:18
Working too for Nullable Properties **public int? Prop2 { get; set; }** or **public DateTime? Prop3 { get; set; }** ? — Kiquenet, Nov 20 '14 at 07:35

ΩmegaMan · Answer 2 · 2014-09-25T01:14:43.683

Here is an extension which will report the standard types such as string, int and Datetime but will also report string lists (shown below in AccessPoints which the above answer could not handle). Note that the output is aligned such as:

Name         : Omegaman
ID           : 1
Role         : Admin
AccessPoints : Alpha, Beta, Gamma
WeekDays     : Mon, Tue
StartDate    : 3/18/2014 12:16:07 PM

Below is the extension which takes in any type as long as its a class. It then reflects off of the public and private properties and if they are not null reports them.

public static string ReportAllProperties<T>(this T instance) where T : class
{

    if (instance == null)
        return string.Empty;

    var strListType = typeof(List<string>);
    var strArrType  = typeof(string[]);

    var arrayTypes   = new[] { strListType, strArrType };
    var handledTypes = new[] { typeof(Int32), typeof(String), typeof(bool), typeof(DateTime), typeof(double), typeof(decimal), strListType, strArrType };

    var validProperties = instance.GetType()
                                  .GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
                                  .Where(prop => handledTypes.Contains(prop.PropertyType))
                                  .Where(prop => prop.GetValue(instance, null) != null)
                                  .ToList();

    var format = string.Format("{{0,-{0}}} : {{1}}", validProperties.Max(prp => prp.Name.Length));

    return string.Join(
             Environment.NewLine,
             validProperties.Select(prop => string.Format(format, 
                                                          prop.Name,
                                                          (arrayTypes.Contains(prop.PropertyType) ? string.Join(", ", (IEnumerable<string>)prop.GetValue(instance, null))
                                                                                                  : prop.GetValue(instance, null)))));
}

Usage

myInstance.ReportAllProperties()

Note that this is based off my blog article C#: ToString To Report all Properties Even Private Ones Via Reflection which provides a more robust explanation of what is going on.

Working too for Nullable Properties **public int? Prop2 { get; set; }** or **public DateTime? Prop3 { get; set; }** ? — Kiquenet, Nov 20 '14 at 07:35

score 1 · Answer 3 · answered Jul 20 '20 at 16:08

I would use JSON, Serializer will do all the hard work for you:

    public static class ObjectExtensions
    {
        public static string ToStringEx(this object obj)
        {
            return JsonSerializer.Serialize(obj, new JsonSerializerOptions { WriteIndented = true });
        }
    }

score 0 · Answer 4 · edited Nov 02 '15 at 11:09

This is what I found, that works with most compicated-types (including List):

public static string ToXml(object Obj, System.Type ObjType)
{
    try
    {
        XmlSerializer ser;
        XmlSerializerNamespaces SerializeObject = new mlSerializerNamespaces();
        ser = new XmlSerializer((ObjType));
        MemoryStream memStream;
        memStream = new MemoryStream();
        XmlTextWriter xmlWriter;
        xmlWriter = new XmlTextWriter(memStream, Encoding.UTF8);
        xmlWriter.Namespaces = true;
        XmlQualifiedName[] qualiArrayXML = SerializeObject.ToArray();
        ser.Serialize(xmlWriter, Obj);
        xmlWriter.Close();
        memStream.Close();
        string xml;
        xml = Encoding.UTF8.GetString(memStream.GetBuffer());
        xml = xml.Substring(xml.IndexOf(Convert.ToChar(60)));
        xml = xml.Substring(0, (xml.LastIndexOf(Convert.ToChar(62)) + 1));
        return xml;
    }
    catch (Exception ex)
    { return string.Empty; }
}

usage:

string classAasString = ClassToXml.ToXml(a, typeof(ClassA)); //whare ClassA is an object

score 0 · Answer 5 · answered Nov 12 '18 at 09:56

I ran into this myself where I am looking for an option to serialize into something readable. If there are no read only properties xml serialization can give a readable string. However if there are read only properties / fields then xml serialization is not an option.

    public static string ToString(object serializeable)
    {
        var type = serializeable.GetType();
        try
        {
            var sw = new StringWriter();
            new XmlSerializer(type).Serialize(sw, serializeable);
            return sw.ToString();
        }
        catch
        {
            return type.FullName;
        }
    }

granadaCoder · Answer 6 · 2020-04-07T19:37:27.413

So I wrote an extension method that calls a library that has already figured out all the voodoo.

"override string ToString()" vs (my) "ToStringDump"....

Before I show the code, the reason I like the extension method (ToStringDump in this case).. better, is that I don't have to riddle my POCO/DTO objects with ObjectDump references. I believe POCOs and DTOs should be "very very clean", and even isolated in their own assembly. This way, these poco/dto objects are easily shared.

public static class ObjectDumpAdapter
{
    public static string ToStringDump(this object obj)
    {
        string returnValue = ObjectDumper.Dump(obj);
        return returnValue;
    }
}

My dotnet core csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFrameworks>netstandard2.0</TargetFrameworks>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="ObjectDumper.NET" Version="2.5.20033.1" />
  </ItemGroup>

</Project>

Nuget link:

https://www.nuget.org/packages/ObjectDumper.NET/

Quote:

ObjectDumper is a utility which aims to serialize C# objects to string for debugging and logging purposes.

(from https://nugetmusthaves.com/Package/ObjectDumper.NET )

GitHub link:

https://github.com/thomasgalliker/ObjectDumper

Dynamic override of ToString() using Reflection

6 Answers6

Usage

Linked